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Argonne National Laboratory's 30-inch hydrogen bubble chamber. High energy particles leave "tracks" of tiny bubbles as they pass through liquid hydrogen in this chamber. These tracks are photographed by special high-speed cameras for later analysis by high energy physicists Argonne National Laboratory Photo Source: The Village Crier Vol. 3 No. 8, February 25, 1971
Source: The Village Crier Vol. 3 No. 21, May 27, 1971 NAL FILM ANALYSIS FACILITY LOOKS FOR SUB-ATOMIC "CLUES" (This is the first of two articles concerning NAL's recently-organized Film Analysis Facility. It was written with the assistance of Ray Hanft, Physics Research; Ernest Malamud, Main Ring; Richard Mobley, Beam Targetry; and Roland Juhala, Booster.)
Some of the most significant and enigmatic mysteries of our time are being viewed almost daily on motion picture film by men and women at NAL who are looking for "clues" that may help unravel nuclear "events." In a white pole building at the northeastern edge of NAL's Village, at 34 Shabbona, is centered the Laboratory's Film Analysis Facility (FAF). There are few like it in the world. Five young women sit quietly at unique tables for long periods, from 8:30 a.m. to 5 p.m. daily, and another joins them at 4 p.m. to work until midnight. All are engaged in "scanning" -- an esoteric, but vital occupation peculiar to elementary particle physics. They are "scanning" films in a search for sub-atomic "incidents" recorded on special photographic equipment at bubble chambers at various physics research laboratories across the nation. Soon, they will be "scanning" such film resulting from complex experiments to be conducted with the assistance of NAL's accelerator system. The Film Analysis Facility group works in an atmosphere of sleek austerity, a sleekness that is incongruous when one learns about the complexity of the work being undertaken there. The facilities are new, with construction still going on. Physicists directing the effort sit in small, cubicle-like offices with their desks piled high with computer printouts which they handle like a housewife hoarding recipe cards. They shuffle through their 10-foot-long cards until they find the right combination for the "dish" they currently are cooking up for their intellectual diets. Many methods are used for recording scientific data from high energy physics experiments. Optical spark chambers and bubble chambers use photographic film to record the capricious trajectories of charged particles. In optical spark chambers, the charged particles produce sparks along their trajectories. In bubble chambers, they produce bubbles along their trajectories. From scanning the photographs of a given particle trajectory from two or more different directions, it is possible to determine the angles and curvature in space of the trajectory. Parenthetically, it might be noted that a liquid detector that grew out of watching bubbles form in a glass of beer led to a Nobel Prize in physics in 1960. Donald A. Glaser, an American physicist, pointed out in 1952 that bubbles will form along the track of a charged particle that has passed through a superheated liquid. The high density of the liquid makes it far superior to the old-fashioned cloud chambers that exhibited jet-like vapor trails for lazy, slow particles but were inefficient for tracking the kangaroo-like trail of super-energetic radiation. At NAL's FAF, bubble chamber film is checked by the "scanners" who carefully review each set of photographs to see if the "events" they discover are "interesting" as defined by physicists who conducted the experiments. (Note: A new elementary particle of matter, the omega meson, predicted for several years on theoretical grounds, was found only after 30,000 photographs had been analyzed at the Lawrence Radiation Laboratory in 1961.) When interesting events are found, information about the trajectories is recorded in digital form suitable for computer analysis. "Scanners" use manually-operated film editing equipment specially designed for their work. NAL already has purchased some such equipment; other items have been loaned by Lawrence Radiation Laboratory at Berkeley, Calif., Brookhaven National Laboratory, New York, and Yale University, Connecticut. The degree of success depends, of course, on the skill, judgment, long-range experience and briefings provided the "scanners." One principal project at FAF now is the development of an "Automatic Measuring Facility" for NAL. The automatic facility will be capable of increasing the rate of scanning and measuring with the aid of semi-automatic control supplied by the DEC PDP-10 computer located in the FAF building. The general complexity of some events, however, precludes the possibility of a fully automatic operation. Hence, in cases where the complexity of the event is beyond the analysis capabilities of the recognition programs in the PDP-10, an operator will be asked to provide objective aid. The net result should be to increase the measuring capability of a single operator by a factor of ten or more. Design of NAL's "Automatic Measuring Facility" began about a year ago, and construction is now underway. First measurement using the automatic device is projected for late 1971 or early 1972, corresponding with the anticipated appearance of the first bubble chamber data from NAL. Physicists associated with this project include Virgil D. Bogert and Raymond Hanft; engineering design work is being done by James DeShong and Robert Cavanaugh. Bruce L. Chrisman and Glenn C. Johnson are working on computer programs for the PDP-10. Technical support for all aspects of FAF is provided by Richard J. Bingham, Delwyn Burandt, Carlos Cangemi, Curtis R. Danner, and Martin Glass. All are members of the NAL Physics Research group. Source: The Village Crier Vol. 3 No. 20, May 20, 1971 FILM ANALYSIS FACILITY GAINS EXPERTISE FOR BUBBLE CHAMBER EFFORTS (This is the second article on NAL's Film Analysis Facility. It was written with the cooperation of Ray Hanft, Dixon Bogert (Physics Research), Ernest Malamud (Main Ring), Richard Mobley (Beam Targetry), and Roland Juhala (Booster).) In simple terms, a bubble chamber is a device used for the detection and the study of elementary particles and nuclear reactions. Charged particles from an accelerator are introduced into a super-heated liquid, each forming a trail of bubbles along its path. The trails are photographed, and by studying such pictures scientists can identify the particles and analyze the nuclear "events" in which they originate. As part of NAL's experimental facilities, work is progressing on a Neutrino Laboratory. It will include a Bubble Chamber area on which foundation work has been completed. A special Bubble Chamber group, under the direction of William B. Fowler, has been concerned with the design of this facility which will have a track length of 15 feet. Work on this target area is scheduled for completion in the summer of 1972; however, it will be available for improvised experimental use several months earlier. It is expected that the bubble chamber will be in operation by January of 1973. In addition, it is expected that the 30-inch bubble chamber which NAL is receiving from the Argonne National Laboratory will be in operation at NAL next November. At present, NAL "scanners" are concerned with analyzing an experiment designed to obtain large numbers of events of the types: K+ + n → K+ + π- + p K+ + n → K° + π° + p Such events when interpreted in terms of a specific theoretical framework can be used to reveal information on the interaction between K and π mesons.
At the Bevatron (the 6 BeV proton accelerator at the Lawrence Radiation Laboratory in Berkeley, California) a beam for selecting K+ mesons passed through a 25-inch diameter bubble chamber filled with liquid deuterium and the chamber was photographed. A total of 800,000 sets of stereoscopic photographs was taken. The deuterium nucleus consists of 1 proton and 1 neutron. When a K+ meson in the beam "interacts" with a neutron "target" reactions of the type listed above may occur. An example is shown at the left. It is the scanner's job to find these events and measure them. In the photograph at the left the particles are bent by a magnetic field. In this particular example the positive tracks curve up and the one negative track (a π meson) curves in the opposite direction. The short stubby track is the recoiling proton in the deuterium nucleus which "observes" the K+ neutron interaction from a distance. This experiment is being done in collaboration with physicists at the University of California, Los Angeles, and the California Institute of Technology. Those associated with the experiment at NAL are Thomas Borak, Radiation Physics; Roland Juhala, Booster,and Ernest Malamud, Main Ring. A spark chamber experiment at Argonne is designed to study the mass spectrum of the A2 meson in the "eta-pi" decay mode via the reaction: π- + p → A-2 + p | → η° + π- | → γ + γ In a double arm spectrometer, the recoil proton is detected in one arm. The π is observed in a thin plate spark chamber in the other arm, and the gamma rays are seen when they convert to an electron shower in a thick plate spark chamber. See illustration at right.
This experiment is being done in collaboration with physicists at the Universities of Chicago, Wisconsin and Toronto. The NAL physicist involved is Richard Mobley. Other physicists involved are: Gianni Conforto, Rutherford Lab.- U.K.; Martin Kramer and David Underwood, University of Chicago; Mike Witherell, Don Tompkins and Dick Prepost, of Wisconsin, and Anthony Key and YuenKwok, University of Toronto. At present, the Film Analysis Facility staff includes the following: Dixon Bogert and Raymond Hanft, physicists; Robert Cavanaugh, engineer; Bruce Chrisman and Glenn Johnson, programmers; Carl Lindenmeyer, designer; Richard Bingham, Arthur Cook, Curtis Danner and Martin Glass, Technical Support; Annette Albano, Dawn Chartrand, Christine Dedin, Barbara Cox, Judy Dill, Teresa Downs, and Harriet Otavka, Scanning and Measuring Staff. Source: The Village Crier Vol. 3 No. 23, June 10, 1971 NAL, CALTECH JOIN IN NEUTRINO STUDIES (EXPERIMENT 21) NAL experienced an interesting, significant and challenging transitional phase - from early construction to operations; from building to research; from bricks and mortar to scientific investigation. One of the first assignments before the world's most powerful particle accelerator was the complex search for a new particle that would help describe nature's mysterious weak nuclear force.
Discovery of such a particle would indicate striking similarities between the weak force and at least two of the three other fundamental forces of nature - the strong nuclear force and the electrical force. Both of these forces have specific particles associated with them, and perhaps the remaining one, gravity, does also. Experiment 21, the goals of which are described in simple terms above, was an NAL-California Institute of Technology collaboration. It was a novel experiment of Barry C. Barish, 35 years old, and Frank Sciulli, 32, associate and assistant professors, respectively, at Caltech. They worked with Alfred W. Maschke, head of NAL's Beam Transfer section, in what was one of the first experiments to be undertaken on the proton synchrotron at NAL. They were selected to investigate neutrino physics during the initial operation of the accelerator and continued until January, 1973. The Caltech-NAL researchers planned to carry their studies on neutrinos up to about 300 BeV. In July 1971, data existed only up to about 10 BeV. The nature of the weak force remains something of a mystery. It is associated with radioactive decay, and its interactions are many billions of times slower and weaker than those of the strong nuclear force, which binds together the protons and neutrons in an atom's nucleus. It was the research team's plan to seek a particle that could carry the weak force. It already has been named. It is called variously the "W," the "Ux1," or the "intermediate vector boson." Evidence suggests the W has a mass greater than that of two protons; this means that the weak force interacts over the extremely short distance of four quadrillionths of an inch or less. The higher the mass of the W, the more difficult it is to produce. The Caltech-NAL experiment, supported by the U.S. Atomic Energy Commission, hoped to produce and detect the particle if its mass is less than about 20 proton masses. The high energy of NAL's new accelerator system makes this possible - if the particle exists. Said Dr. Sciulli: "We were able to probe more deeply than hitherto possible into the proton and the neutron. This helped us understand more about their structures and the forces associated with them. We may learn more about the electrical force because indications are that the weak force is related to it." A small but distinguished group of physicists conducted the experiment at NAL with Barish, Sciulli and Maschke. They include Les Oleksiuk of the NAL Beam Transfer section; and from Caltech: Charles Peck, associate professor of physics; Yorikiyo Nagashima, senior research fellow; William Ford. Dennis Shields (research fellow) and Tom Humphrey, thesis student. George Krafczyk, NAL technician, assisted in installing the experiment.
Members of the Caltech physics faculty and several Caltech students came to NAL in March 1971, preparing for this early experiment. They worked in what was a cornfield between Batavia and McChesney Roads and to the east of Wilson Road. The lights rarely went off at the "Wonder Building"; they were on day and night, weekdays and weekends, as the team completed the special equipment designed and built for this experiment. The "Wonder Building" had a dirt floor, no framing, and featured bottled water and chemical toilets. It was truly an austere "Wonder Building" but it contained some of the most advanced scientific equipment for elementary particle research in the world. During the school term at Caltech, the faculty members commuted from California to NAL, in order to maintain their teaching commitments and to prepare for the experiment at the same time. The Barish, Nagashima, and Sciulli families then resided in the Surrey Hill apartments in St.Charles; the Caltech students working with the project lived at "The Pad" - a dormitory-type facility located at 32 Sauk in the NAL Village. The professors and their families returned to California in the fall and resumed their commuting-teaching-experimenting schedule. Robert R. Wilson, NAL Director, told the NAL Users' Organization, at their annual meeting, that the first aim of experiments on the NAL accelerator system was the detection of a neutrino. "I feel that we then will be in business to do experiments on our accelerator, and I feel that this detection will come in the Caltech-NAL experiment. The Caltech installation excites my envy - their enthusiasm and improvisation gives us a real incentive to provide them with the neutrinos they are waiting for." The new accelerator made it possible for the first time to observe the behavior of the weak nuclear force at high energies. In July 1971, knowledge of this force was based primarily on decays of heavy particles at low energies. Drs. Barish, Sciulli and Maschke developed a very high energy beam of neutrinos - a product of weak force interactions - for this investigation. The beam was unique in that its design allowed the experimenters to specify the energy of the neutrinos that they wished to investigate. Source: The Village Crier Vol. 3 No. 28, July 15, 1971
U. OF CHICAGO SYNCHROCYCLOTRON TO FIND NEW HOME AT NAL NEUTRINO LAB To date [September 1971], 155 proposals have been received from the high energy physics community to conduct experiments on NAL's accelerator system. Of these, 52 have been approved by the program advisory committee. One approved research effort is designated as Experiment No. 98. It will be a complex endeavor involving, literally, some of the heaviest equipment on the NAL site. Scientists from Oxford University, Harvard, the University of Chicago and NAL will be involved, as well as distinguished physicists from the United States and Great Britain. So that Experiment No. 98 and others can be conducted here, the 2,500-ton magnet from the University of Chicago synchrocyclotron, built nearly five decades ago, is being moved nearly 45 miles from the University campus to NAL. Sometime this fall, the heavy magnet will be placed in the muon experimental area of the NAL Neutrino Laboratory. A special building will be constructed to house the magnet near the "Wonder Building," not far from Wilson and McChesney roads. Experiment No. 98 is scheduled to begin July 1, 1972. However, it is expected that the magnet, and supporting facilities, will be in place by late next Spring [actually, Spring 1973]. "We will be very happy to have this valuable piece of equipment available at NAL since it would have cost much money and involve a great deal of time to duplicate it." With those words, Taiji Yamanouchi, physicist on the NAL Neutrino Laboratory staff, greeted the news that the University of Chicago's synchrocyclotron, was being moved to NAL. A main part of the early model particle accelerator will be used as an analyzing magnet to study the structure of the proton using muons as a probe. It will be a heavy moving job from the synchrocyclotron's home near 57th Street and Ellis Avenue in Chicago's Hyde Park district to the NAL site, a distance of about 45 miles. The Experiment No. 98 team will study the scattering of high-energy muons from targets made of liquid hydrogen and other materials. The experiments will utilize the proton beam from the NAL accelerator. Dismantling of the synchrocyclotron began July 12 under the direction of Leroy Schwarcz, the chief mechanical engineer who built it in 1950-52. Schwarcz is now [was in 1971] a senior staff member at Stanford Linear Accelerator Center (SLAC). S. Courtenay Wright, Professor, Department of Physics, the Enrico Fermi Institute, and the College of the University of Chicago, helped make plans for moving the magnet to NAL. Schwarcz is now [September 1971] directing the removal of 3,700 tons of concrete shielding that protected staff and researchers from radioactivity from the synchrocyclotron when it was in operation. The concrete rests in two layers of concrete beams that weigh 80 tons each, covering most of the pit containing the synchrocyclotron. It is expected that the synchrocyclotron will be totally dismantled at the University about October 15. Shipping of the components of the magnet are scheduled to start that day. It will require 22 truckloads, with one 90-ton segment magnet on each truck, to accomplish the transfer, according to Robert G. Sachs, Professor in the Department of Physics and Professor and Director of the Fermi Institute Sachs noted that some of the synchrocyclotron's greatest work was being done right up until the last minute of its operation, 8 a.m., July 12, 1971 on an experiment involving muonium by Valentine L. Telegdi, Professor in the Department of Physics and the Institute, and his collaborators. Muonium is a man-made atom of a fleeting life consisting of a positive mu meson and an electron. Telegdi's experiment involved ultra-high precision measurements which give new information on the fundamental constants of physics. In the early 1950's, the synchrocyclotron's 450 MeV (450 million electron volt) proton beam was one of the world's prime sources of mu and pi mesons (muons and plons)" opening up a whole new field of science-particle physics. Since then, a bewildering variety of "new" subatomic particles has been discovered in research using particle accelerators. The purpose of the experiment at NAL is to investigate the basic structure of the proton, one of the basic building blocks of matter. High energy muons produced at NAL will be used, much as X-rays are used by physicians, as the probe. Source: The Village Crier Vol. 3 No. 38, Septermber 23, 1971 
A line drawing showing the major elements of the NAL 15-foot Bubble Chamber
Thank you, Delphi, Indiana...Waukesha, Wisconsin... Birmingham, Alabama... and several other points east and west. The major component of the 15-ft. bubble chamber arrived by rail at NAL on October 25th, 1971 the last stop in a nationwide design and fabrication effort that began in 1970. The 39,000-pound bubble chamber is a sphere of 12 1/2-foot diameter of 1 1/8" thick 316L stainless steel, topped by a 9-foot-diameter hemispherical "optics head." Six strategically-located "camera nozzles" allow stereo views of bubble tracks when the chamber is operational. A stainless steel "cooling jacket" also lined the inside of the "optics head." Fabrication of the various parts resulted from the efforts of Wisconsin Centrifugal Company, who constructed the camera nozzles in Waukesha, Wisconsin; Canadian Lukens of Rexdale (Toronto), Canada, who built the optics head; Alloy Crafts of Delphi, Indiana, the cooling jacket. Chicago Bridge and Iron constructed the remaining portion of the chamber in Memphis, Tennessee and Birmingham, Alabama. Final assembly was completed in the Chicago Bridge and Iron Birmingham plant. Total cost of the chamber was $250,000. The large chamber vessel was carefully delivered from the railroad siding at the north edge of the site to the NAL Village by a Belding Engineering crew on a beautiful 75o Indian Summer day. The arrival heralded a significant step in the construction progress at NAL. The NAL 15-foot bubble chamber operated at liquid hydrogen temperature of -423 F and underwent rapid pressure changes during each accelerator pulse. Millions of photographs were taken during the life of the chamber. When operating, the chamber was filled with liquid hydrogen, deuterium, or a mixture of hydrogen and neon. One of the beams available in the chamber was a beam of hadrons. In this case, the particles entered the liquid through a thin stainless steel beam window on the accelerator side of the chamber. The interactions of these particles in the liquid were photographed by cameras viewing the chamber through the optics nozzles. Another beam consisted of neutrinos. In this case, the weakly-interacting neutrinos were dispersed over the entire area of the chamber wall and these interactions were photographed. The 15-foot chamber used with the NAL accelerator produced hopes for exciting new discoveries in the frontier field of particle physics and was expected to be particularly useful in experiments to further our understanding of the role of the elusive neutrino. The entire Bubble Chamber staff worked hard to make the chamber operational. They accomplished an enormous amount of work in a short span of time. In November, 1971 the chamber was moved to its final position in the Bubble Chamber Building at the corner of Road A and Wilson Road, where it was installed inside a 22-foot-diameter vacuum sphere and the completed installation became a part of the Neutrino Laboratory system. Source: The Village Crier Vol. 3 No. 44, November 4, 1971 ALL SYSTEMS GO!
The 30" hydrogen bubble chamber which was moved from Argonne National Laboratory in summer of 1971 to the Bubble Chamber area of the Neutrino Laboratory at NAL, was successfully tested in its new home on November 9th, 1971. Tracks of cosmic rays and of secondary electrons from gamma ray sources were observed. From April of 1964 until April of 1971, the chamber was one of the main research facilities at Argonne. Over 50 experiments (a total of nearly 14 million pictures) were performed for groups from the major research centers in the U. S. The chamber was originally constructed for use at the Argonne zero gradient synchrotron (ZGS) by a Midwestern Universities Research Association group in Madison, Wisconsin, under the direction of Dr. W. D. Walker of Duke University. Dr.Walker also be worked on experiments done with the chamber at NAL. As plans for experiments at NAL evolved from 1969-71, it became apparent that a bubble chamber facility should be available at NAL as soon as beam was available. An agreement was reached between NAL and ANL in December of 1970, and in April 1971 plans were completed for the buildings and major services to be provided for the new facility by NAL, while ANL accepted responsibility for the move and installation aimed at initial operation of the bubble chamber at NAL in November, 1971. Argonne also operated the facility during the first year of its use in experiments at NAL. Dr. Louis Voyvodic, who had been group leader of the 30-inch bubble chamber section at Argonne, had also directed the reactivating operations at NAL. "The uniquely high optical precision and the unusually high magnetic field of 32,000 gauss in this chamber will play important roles in the experiments to be performed at NAL," he noted, "building on the proven performance already achieved with this facility at Argonne." Approved plans for experiments with this bubble chamber are thus described by Dr. Voyvodic: "First, a series of eight 'quickie' experiments with the 'bare' chamber were scheduled, utilizing the full energy range of NAL proton and meson beams, in order to survey the kinds of interactions which can be studied for the first time with these particles."
A group of Argonne scientists who are especially familiar with this chamber conduct the first experiment. Other "quickie" experiments included researchers from NAL, UCLA, Brookhaven National Laboratory, CERN, University of Michigan, University of Rochester, Lawrence Berkeley Laboratory, and University of California at Davis. "Next," says Dr. Voyvodic, "came a systematic experiment in which the chamber were aided by a hybrid system with wide gap optical spark chambers." Four laboratories-Michigan State University, Iowa State University, University of Maryland and Argonne carried this work out, with additional participation by Duke University, University of Toronto, Purdue University, University of Notre Dame and University of Wisconsin. And, "additional experiments were conducted by another group of nine laboratories who provided further wire-chamber and computer instrumentation to enhance the hybrid capabilities of this unique bubble chamber installation," according to Dr. Voyvodic. The successful testing of the chamber in its new surroundings started on November 1, 1971, when the main components began a "cooldown" reaching down to 450 degrees below zero (-450°F). At this temperature, controlled boiling of liquid hydrogen was achieved to produce particle tracks on November 9th. During the checkout tests of the chamber, the electrical power supply for the powerful magnet in the system arrived from California. This was readied to allow full experimental operation, with the bubble chamber group pausing occasionally to check on progress at the NAL Main Ring. The 100 to 500 BeV beams brought exciting events to this group of scientists in the Bubble Chamber area. Source: The Village Crier Vol. 3 No. 47, December 2, 1971
Source: The Village Crier Vol. 3 No. 49, December 16, 1971 PHYSICISTS IN EXPERIMENT NO. 26 FIND A NEW HOME
Equipment and apparatus for NAL Experiment No. 26 were moved into the Muon Laboratory in the Neutrino Laboratory area during January, 1972. Two main groups of experimenters were involved in setting up the apparatus since July, 1971. They previously worked in the Industrial Building #3 in the Receiving Department, awaiting the completion of the Muon Laboratory. The group from Michigan State University consisted of K. Wendell Chen, Don Fox, Paul Kunz, Chuen Chang and David Chapman. The collaborating group from Cornell included Lou Hand, Stu Loken, Yasushi Watanabe, and Bruce Meyer. Also Mark Strovink, affiliated with both Cornell and Princeton and Wayne Vernon from the University of California at San Diego participated in this experiment. Some of these physicists are already familiar faces on site since they have been interacting with NAL staff members frequently during on and off hours for many months. These physicists were interested in using the muon beam which emerged parallel to the neutrino beam. Their aim was to study the electromagnetic structure of the proton by studying muon scattering.
Source: The Village Crier Vol. 4 No. 5, February 3, 1972
Schematic layout of NAL Neutrino Laboratory located parallel to Road A-l extending northeasterly from the footprint area
The pursuit of the elusive neutrino particle was one of the liveliest races on the NAL program. Capable of going through the entire earth without interacting with anything, the weightless neutrino can be observed only when a great number are present. The high energy and intensity of the NAL beam produces an abundance of neutrinos of high enough energy to permit study of the so-called "weak interactions." The NAL Neutrino Laboratory provided the facilities for this study. In the Target Hall of this Laboratory, the proton beam from the Main Ring smashed into a miniscule target - a tiny rod of aluminum measuring .1 inch by .2 inch - and this collision broke up the nuclei of the target. The debris of this crash resulted in formation of pi mesons and k mesons, with a lifetime of 1/100 millionth of a second. Their death, or decay, in turn produces the neutrino. The Neutrino Laboratory runs along Road A-l, one mile in length. In this vast expanse of facilities, staff members have been working diligently for the past two years on the construction of four beam lines and the conventional facilities that carry neutrinos and muons (another particle produced as a by-product of neutrino production) to experimental halls.
A 6 ft. diameter target tube, buried under 30 feet of earth shielding, is the main feature of the Target Hall. The neutrino targetting system consists of a 200-ft. long arrangement of magnets and detectors, in the heart of which is the tiny aluminum rod that is the actual target. The entire array is mounted on a narrow-gauge railroad train on a track built into the tube so that the target may be inserted into the tube during operation or may be withdrawn into the tunnel of the Target Hall to be worked on. Next in the Neutrino Laboratory line is a 1300-ft. long, 3 ft. diameter vacuum pipe. In this pipe the neutrinos are born, in the decay of pi and k mesons following the collision of the beam on the target. From here, various magnets, power supplies, control stations and particle detectors located in twenty small buildings along the neutrino line guide the newborn particles to the appropriate experimental area. Two neutrino experiments. Experiment 21, an NAL-Caltech group, in the Wonder Building, and Experiment 1A (a collaboration of Harvard, Penn. and Wisconsin) in Building C of the Bubble Chamber area, presently set up and ready to take data. One muon experiment. Experiment 26 (involving Cornell, Michigan State, and University of California, San Diego) is ready to register beam. Running the entire length of the Neutrino Laboratory are two lines that will carry charged particles to the 30-inch Bubble Chamber (known as Beam N-3) and to the future 15 ft. Bubble Chamber (designated as Beam N-5). The N-3 beam line was the focal point of 1972 efforts, getting it ready to accept protons from the Main Ring, target them, and deliver sorted and tagged particles to the appropriate experiment. Physicist Timothy Toohig, has directed much of the development of the Neutrino Laboratory. His group merged with the Bubble Chamber group in April 1972 and the combined section is headed by William Fowler. Dr. Toohig explained for THE VILLAGE CRIER the organization that was responsible for the Neutrino Laboratory: "Preparation of the area has been an ecumenical effort involving many people and groups," Dr. Toohig reports. "Staff physicists are Joe Lach, Frank Nezrick, Ray Stefanski, Yong Kang. Stan Pruss, Taiji Yamanouchi, with collaboration of Al Maschke, Les Oleksiuk, and with Phil Livdahl in the Godfather role. Jim San ford developed key concepts for the area. "The core group of the installation effort was Frank Krzich, Reid Riliel, Leon Beverly, Max Palmer, Waynei Nestander, Russ Winje, Jan Wildenradt, Don Carpenter, John McCarthy, Gene Woods, Jim Walker, Jack Lindberg, John Simon, and Frank Mallie," Dr. Toohig explained. "Essential to the whole effort were the Controls Group under Bob Daniels, and the Alignment Group under Bill Testin. Tom Pawlak was the DUSAF representative." He continued, "Miguel Awschalom and his stalwart staff kept us always honest radiation-wise, and, finally, Ginny Linguist has kept typing typed and the coffee warm." Source: The Village Crier Vol. 4 No. 18, May 4, 1972
MAGNET TEST COMPLETED SUCCESSFULLY
Early on the morning of Monday, October 10, 1972, the superconducting magnet that is an integral component of the NAL 15-foot Bubble Chamber, finished its first test run with complete success. The magnet reached its full design parameter - 30 kilogauss central field (about fifty thousand times the earth's magnetic field) - about 5 a.m. after men and machine had been tested with equal intensity for several weeks. Filling of the magnet with liquid helium was completed on Sunday, October 8, and once full of liquid, the magnet was energized and progress was rapid. The 150-ton magnet surrounds the 15 ft. Bubble Chamber. Its purpose is to act on particles that come from the Main Ring into the chamber by bending the track of the particles so that one may be distinguished from another in the photographs that are taken from the top of the chamber. The high energies obtained with the NAL accelerator mean that the particles are traveling at very high speeds. The magnetic field must be large enough to bend these speeding particles. This magnet is one of the most powerful and most advanced in the world today. The physical parts of the magnet are fully enclosed in a container filled with liquid helium. The testing that had been underway since September 6 involved first cooling the magnet, about one degree per hour, down to close to absolute zero (-452.1 degrees F) to achieve the physical effect known as superconductivity in which materials at this low temperature lose resistance to the flow of electricity. In conventional electromagnets, heat is produced because of the resistivity of the current-carrying conductor. Considerable power is used in producing this heat, and that power is simply wasted. Since there is no resistance to current flow in a superconducting magnet, no heat is produced and therefore no power is lost. A relatively small source of electrical power is needed to charge the magnet and electric power is used primarily to keep the refrigeration operating. The saving in power cost over the long run will be substantial.
To take advantage of the expertise accumulated at the Argonne National Laboratory during the construction of Argonne's 12-foot bubble chamber several years ago, and to minimize the burden on the staff at NAL for constructing the 15-foot chamber here, the decision was made to have Argonne build the magnet for NAL. This joint effort between ANL and NAL proved to be very satisfactory. During the two-year span of the project, ANL and NAL staff worked side by side toward successful completion. The project finished within budget estimates, and the cooperation enabled NAL staff to learn of the machine as it was built and to be ready for operating when it was finished. Argonne personnel who worked on the project included John Purcell, Henri DesPortes (visiting scientist from Saclay), Tom Cameron, Karl Mataya, Bruce Millar, and Dick Jones (deceased). John Purcell spoke of the successful test run by saying, "After going through the tests of the ANL 12-foot bubble chamber magnet, this test was more like a routine run than a test. I would like to thank the NAL operating crews for helping make this the smoothest test in big magnet history." Members of the NAL Bubble Chamber staff working on shifts during the cooldown were: R. Ahlman, George Athanasiou, F. Bellinger, D. Curtice, R. Davis, J. Fogelsong, H. Kautzky, J. Kilmer, Mike Morgan. George Mulholland, R. Niemann, W Noe, J. Stoffel, J. Thompson, and J. White. Also contributing to the magnet construction efforts were: Steve Johnson. George Simon, Paul Thorkelson, David Oprondek. Hoyt Smith, Art Skraboly, Lee Mapalo, George Nosal, Harry Stapay. William Fowler headed up the Bubble Chamber work at NAL, assisted by Russell Huson. NAL 30" Bubble Chamber personnel who lent their assistance to the project included: Dick Brazzale, Jim Harder, Gary Hodge, P.P. Keefer, George Powell, Vance Sauter, Fred Walters and Del Q. Wilslef. Hans Kautzky, one of the NAL people most intimately concerned with the construction, described the main components of the huge magnet: An upper and lower coil stack each consisting of more than twenty "pancakes." A "pancake" has three layers - spiral wound from a stainless steel strip for strength, then a mylar strip for insulation, and then a copper strip embedded with superconducting strands (60 strands, each only 15/1000 inch thick) conducting all current (5,000 amps.). The pancakes are stacked, then joined by soldering. The vacuum-tight helium can surrounds this stack. Only two small openings - one for cooling equipment and one for power leads - can be found on top. Layer after layer of super-insulation surrounds the can, up to an outer stainless steel skin which is welded all around. Precise, accurate workmanship was necessary at every step because, once closed, the magnet is a completely-sealed unit and none of the components can be reached. Main technical parameters of the magnet are: Field in center: 30 kilogauss. Bore diameter: 14 feet; height 10 feet. Stored energy: 400 megajoules. George Mulholland who was in charge of operations during the test, viewed the achievement as follows: "The magnet and its cryogenic system grew out of a marriage of national laboratories, industry, and consulting firms. The totally successful nature of the first test was a credit to all those involved and particularly satisfying to those of us who get to move on to the next Bubble Chamber challenge."
Source: The Village Crier Vol. 4 No. 34, October 19, 1972 CALTECH GROUP DETECTS NEUTRINOS In 1971, NAL Director Robert R. Wilson told the Users' Organization that "one of the first alms of experiments on the NAL accelerator system will be the detection of a neutrino. I feel that we then will be in business to do experiments on our accelerator..." Neutrinos, which have neither charge nor mass, are very difficult particles to detect experimentally. They play a very prominent role in the study of the weak interaction, because they only interact via the weak force, about which relatively little is known. Months have passed since this comment was made, many long hours have been devoted to completing and refining the NAL accelerator, and Dr. Wilson's wish for the detection of a neutrino has been fulfilled. The Experiment 21 group, headed by Professors Barry Barish and Frank Scuilli, from the California Institute of Technology, detected neutrinos in their apparatus last November. They are making tests in the neutrino beam in anticipation of measurements they hope to pursue in 1972. It was an exciting time for all those connected with the experiment. At the February 7th Director's Meeting, Dr. Barish described recent developments in the Wonder Building: "As most people know, in November 1971 we first saw neutrinos, which at that point wasn't much more than proving to us that the accelerator really existed and something came out. We were set up in a mode where all we could do was see neutrinos interact -- we couldn't even attempt to look at the properties of high energy neutrino interactions. We were over-constraining ourselves in as many ways as possible, in order to make sure that we could really detect neutrinos and believe it. By January 1972... fortunately the energy of the machine went up to 300 GeV and we got something like 3 x 1016 protons on our target, which gave us our first opportunity to obtain a reasonable number of events. Quite a few people who were around here at the time actually saw events coming in. At one time, for example, we had two events on successive pulses, which seems to be a record. Since then we looked very hard at what we had. We saw some examples of neutrino interactions of over 100 GeV. Over half of our events were analyzable, and for a first attempt, that's encouraging. We know what we have to do to get at the rest, and we're just in the process of trying to understand and improve the apparatus, beam, and so forth. We have lots of tests to make, but I don't think it will be very long before we'll be able to say something. Right now, however, we remain very, very silent."
The Caltech group conducted more tests to be sure their apparatus was working properly and determined which "pieces of physics" were sensible to pursue with it, and then finally, to complete the experiment. Their experiment was assembled with the help and support of the NAL Neutrino Section. The Caltech experimenters consisted of a small, dedicated group. Dennis Shields built and installed much of the equipment one sees in the Wonder Building. The sophisticated ON-LINE data acquisition system used in the experiment was developed by Fritz Bartlett. George Krafczyk of NAL made important contributions to almost every facet of the experiment. David Buchholz and Henri Suter, (a CalTech visitor from University of Geneva) joined the experiment, adding both new stimulation and an international flavor to the group. Al Maschke, from Brookhaven National Laboratory and Yori Nagashima, who has returned to Japan, also contributed. CalTech thesis students, Tom Humphrey and Frank Merritt, were the real heart and soul of the experiment. What the group next hopes to investigate is the behavior of the weak interaction - force - at the very high energies possible with the NAL accelerator. The weak interaction has been studied extensively in decays of unstable particles and radioactive nuclei, in which the energy released is in the range of approximately zero to 500 MeV. For a number of theoretical reasons, physicists expect that the picture of the weak interaction which has emerged from such particle decay experiments will change when higher energies are used, although the precise nature of the change remains conjecture. New phenomena, or even a new particle, may be discovered. No carrier of the force - a field particle, so to speak - has as yet been identified for the weak interaction, although the so-called W-particle or intermediate vector boson has been postulated. It just might be produced at higher energies. Nobody knows. Experiments at CERN using neutrinos at energies up to 10 GeV showed no noticeable deviation from the known theory of weak interactions. Neutrino physics is so interesting and exciting that several other experiments were approved, including those for the 15-foot Bubble Chamber. Whether the NAL accelerator, which yields neutrino energies more than ten times greater than any studied to date, will provide enough energy to see any new phenomena or to prove the existence of the W-particle and thus, further explain this puzzling nuclear force, remains to be seen. If it does, as Dr. Wilson enthusiastically remarked at that same Director's Meeting, "just that one thing will make the whole Laboratory worthwhile." Source: The Village Crier Vol. 5 No. 8, March 1, 1973 NAL EXPERIMENT SEARCHES FOR MAGNETIC MONOPOLE
Some of the experimental work done at the National Accelerator Laboratory continues lines of scientific thought that have been a part of man's intellectual aggregate for many centuries. Democritus in Greece four centuries before Christ, the Aristotelean theories, and, in some sense, many years of the mysticism of alchemy -- all have been part of the train of thought which searched in depth for an understanding of the internal structure of all matter. Speculations concerning the possibility of magnetic monopoles are undoubtedly some of the oldest elementary particle ideas around today. The first compass came into use in the 1200's, described by one Peter Peregrini as having "a north pole and south pole." The burst of intellectual thought in the 1800's brought Faraday's explanations of magnetism along with Clerk Maxwell's equations describing the inter-relationship of electricity and magnetism, but raising one question which exists to the present: Complete symmetry between electricity and magnetism could exist if there was a particle with a magnetic pole (a magnetic monopole) comparable to a particle which has one electric charge. In the flurry of scientific discovery since 1800 and the tidal wave of accompanying technology, ideas about the possibility of a magnetic monopole have been considered but the hunt was not vigorously pursued. In 1973, new speculations were made about the possibility of a magnetic monopole. A search of deep ocean sediment in 1969 as well as a study of samples of moon rock in 1970 failed to find any magnetic monopoles, but did not diminish interest in its possible existence. The NAL accelerator offered Frank Nezrick, R. Carrigan and B. Strauss an opportunity to begin the search at NAL for the magnetic monopole. The high intensity of the NAL machine gave a much higher flux of protons than the cosmic rays in the natural material used by experimenters before 1973. In a report to the American Physical Society meeting in Washington , Nezrick said, "The experiment is simple in conception. The proton beam strikes an iron beam 'dump.' Any magnetic monopoles that are created stick to the iron because of magnetic attraction. Later the dump is exposed to a powerful superconducting electromagnet which is strong enough to rip the monopoles away from the iron and accelerate them through a series of special electronic counters where they are identified and recorded." About fifty 3/8" X 1" X 1.5" target blocks were exposed for 161 hours in Phase I of this experiment at 300 BeV. The experimental equipment was then dismantled and a portion brought to the Village which contained the exposed targets. Because these targets were radioactive, the situation was used as an opportunity for the Target Handling group to demonstrate its ingenious device with electronic fingers for handling radioactive equipment. The device permits an operator to remotely handle radioactive material. The electronic robot daintily picked up the targets, and then placed them in boxes which could be moved to the detector equipment. In a tense, exciting two hours, Nezrick, Carrigan and Strauss, working along with M. Otavka, fed the targets through their detecting equipment and in the tradition of the scientists who have passed before us, watched for evidence of the elusive particle. No magnetic monopoles were found in this first phase of the experiment. Targets collected during a 400 BeV run have yet to be analyzed. Further exposures are planned in the Neutrino Laboratory with even longer proton runs. "If a monopole is there, we have an excellent chance of finding it," Nezrick feels. Source: The Village Crier Vol. 5 No. 20, May 24, 1973 CHICAGO MAGNET CONTINUES PARTICLE RESEARCH AT NAL
NAL's Neutrino Section is completing its refurbishing of the 2500-ton magnet brought to NAL in 1971 and 1972 from the University of Chicago. Once the world's largest particle accelerator, a synchrocyclotron with an energy of 450 million electron volts, the Chicago machine's life ended July 12, 1971. Within a few months it had been dismantled and the magnet from the machine began its journey by rail to NAL. The 53 pieces were re-assembled in the Muon Area of the NAL Neutrino line where the magnet served as a spectrometer to sort particles by momentum for experiments done there. Gene Woods, NAL engineer who directed the magnet power supply installation, reported that the magnet was brought to a field of approximately 13.6 kilogauss at 3,800 amperes on June 21. A change was made to an SCR-controlled power supply instead of the original generator-driven power supply, and the magnet was reworked to have a wider gap. The synchrocyclotron was an important facility at the University of Chicago and is referred to with affection by scientists who have used it. Many of the important original discoveries about subatomic particles were made by experimenters there. Among the people working there were Herbert L. Anderson and S. Courtenay Wright, professors in the Department of Physics and the Enrico Fermi Institute at Chicago. These two men and Luke Mo, assistant professor in the Department of Physics and the Fermi Institute, directed the University of Chicago portion of the first collaboration to use the magnet at NAL. Their installation also included massive steel blocks carved from the remains of a cyclotron built at the University of Rochester in the 1950's and discontinued about the same time as Chicago's. A second generation of workers claimed the venerable piece of equipment, and it began what Dr. Wright referred to as "its phoenix," a second life emerged from the ashes of its first.
The work at NAL was under the direction of the NAL Neutrino Section headed by R. Orr, assisted by T. Toohig and W. Nestander. Installation of the coil was done by R. Rihel, Frank Mallie, Ross Doyle, R. McCracken and E. Laukant of Technical Services performed valuable liaison. Electrical controls' installation and fabrication was handled by W. Williams, J. Walker, K. Roy, C. Worel, G. Ross, L. Beverly, and P. Burton of the Oxford Experimental Group. Source: The Village Crier Vol. 5 No. 28, August 9, 1973 NAL 15-FOOT BUBBLE CHAMBER COMMISSIONED
The largest liquid hydrogen bubble chamber in the world was successfully operated for the first time at 5:15 p.m., Saturday, September 29, at the National Accelerator Laboratory. Tracks of particles using the NAL Main Accelerator were photographed as they traveled through the liquid hydrogen of the NAL 15-Foot Chamber. The new Chamber is located at the end of the NAL Neutrino Experimental Line. The event marked the successful completion of three years of effort by one of the Laboratory's most dedicated teams. The highly-skilled group had worked round the clock for several days to fill the Chamber with liquid hydrogen. As the Chamber slowly filled, it was possible to look down, with the aid of a periscope, into the pool of colorless, very cold liquid, boiling near absolute zero temperature (-423° F). In operation, the Bubble Chamber is somewhat analogous to an ordinary gasoline engine. A gigantic piston six feet across keeps the liquid hydrogen under pressure. At a signal from the Control Room, the piston drops more than four inches in about 60/1000ths of a second, lowering the pressure on the Chamber and expanding the liquid. The noise of the expansion reverberates through the building housing the Chamber, like a powerful rendition of the anvil chorus. The effect of the expansion is similar to shaking a soft drink; bubbles appear in many places, but they also make the paths of the particles which have passed through the Chamber visible. Expansions were begun very carefully when the Chamber was brought into operation Saturday. At first, piston motions of only a small fraction of an inch were used. The system was watched carefully for any small motions that might indicate a misalignment. Gradually, as confidence built in the system, the piston stroke was increased. Right at the predicted stroke length, particle tracks became visible in the liquid, thereby signaling the successful commissioning of the NAL 15-Foot Bubble Chamber. The Bubble Chamber Group has been led by Dr. William Fowler, one of the leading bubble chamber authorities in the world. Prior to joining the staff at NAL, Dr. Fowler had been a central figure in the very successful bubble chamber team at Brookhaven National Laboratory. Also playing a key role in the design and construction of the NAL Chamber have been scientists R. Huson, H. Kautsky, G. Mulholland, and W. Smart. They brought together at NAL an outstanding team of technicians and scientists, many with years of bubble chamber experience, for the complex and painstaking assembly and testing of the 15Foot chamber.
A crew of 27 employees will be responsible for operation of the Chamber. They include engineers F. Bellinger, D. Curtice, and J.B. Stoffel; engineering aides and tech nical specialists, A. Newman, W. Noe, C.B. Pallaver, and P. Thorkelsen. Technicians in this phase of 15-Foot operation are: R. Ahlman, G. Athanasiou, E. Beck, A. Coleman, J. Colvin, R. Davis, M. Diveley, R. Ferry, J. Foglesong G. Gadow, S. Johnston, J. Kilmer, C. McNeal, C. Pitts, G. Simon, R. Stoever, R. Thompson, S. Tonkin, J. White, and J. Woodworth. Another crew will be responsible for research and development. This group includes engineers H.K. Feng, K. Kula, and M.W. Morgan. J.W. Thompson is technical specialist for this phase; C. Mangene and L. Robinson, technicians; designers are L. Mapalo, A. Skraboly, and H. Stapay. The 15-Foot Chamber is greatly aided by an office staff headed by E. Renaud, and including D. Augustine, N. Johnson, and M. Richardson. Also deeply involved in the Bubble Chamber effort has been the NAL Machine Shop. L. Chipless and Bob Jackson contributed to the final stretch effort. J. Ramus and S. Alexander of the Machine Shop are now permanently stationed in .the Assembly Building of the Bubble Chamber Area. Bubble chambers were first invented by Donald Glaser of the University of Michigan in 1952. The bubble chamber method, with its accompanying photographs allows detailed, careful analysis of the events which occur when sub-nuclear particles interact. Glaser, now primarily interested in biophysics, was awarded the Nobel Prize in 1960 for his invention. Much of the present form of bubble chambers was developed by the Lawrence Radiation Laboratory at the University of California for which Professor Luis Alvarez was awarded the Nobel Prize in 1968. Over the years, bubble chambers have grown enormously in size and effectiveness. Roughly half of the discoveries in sub-nuclear physics have come from bubble chambers. The discovery of the omega minus particle in a bubble chamber at the Brookhaven National Laboratory chamber was a particularly famous example. The omega minus particle completed a "missing link" in the sub-nuclear zoo, and allowed confirmation of the present day particle classification scheme. University physics departments have found research with bubble chamber photographs to be particularly useful to them because the analysis of the photos could proceed as time permitted on equipment that was readily available at university laboratories. At NAL, study of both the 15-Foot and the 30-Inch Bubble Chamber film is aided by the Film Analysis Facility presently located at 34 Shabbona.
The 15-Foot Bubble Chamber Group reached a major milestone on October 26, 1972 when it successfully tested the 150-ton circular superconducting magnet which surrounds the Chamber. The magnet, which produces a magnetic field of 30 kilogauss, was a significant development in itself, a joint project between NAL staff and a group from the Argonne National Laboratory. The magnet was not operated as part of last Saturday's test. The expansion system was also a joint project between NAL staff and a group from the Stanford Linear Accelerator Center, Palo Alto, California. The collaboration and cooperation between the national laboratories contributed significantly to the success of the NAL 15-Foot Bubble Chamber. This cooperation will certainly prove valuable in future projects. The next phase of reaching routine operation with the 15-Foot Chamber will be to add the operation of the magnet to the sequence. The magnet serves to bend the particles as they come racing through the hydrogen; they can then be more clearly distinguished, identified, and studied. The successful expansion of the Bubble Chamber followed by less than a week the first pulsing of the NAL neutrino horn on Saturday, September 22 at 9:30 p.m. Within minutes, the system was operating at the full design value of 150,000 amperes. The system operated over the weekend with only minor interruptions accumulating 12,000 pulses by Monday morning. The horn gives the Neutrino Line greatly enlarged focusing power, allowing a well defined beam of neutrinos to continue down the Neutrino Line. The first tests included operating the full pulsed power supply, the current polarity reversal switch, the complicated three-plate current transmission line, and the neutrino horn itself. The success of the first trial attests to the quality of the design and workmanship carried out by another "NAL Team" as well as to their tenacity in meeting difficult construction deadlines. Frank Nezrick headed the Horn project. Russ Winje, with the help of the Neutrino Section technicians, contributed a pulsed power supply of great flexibility and versatility. Glen Lee, with the help of Main Accelerator draftsmen, supervised the design of the mechanical elements of the horn system. Luther Hardy and the Hi-Rise Machine Shop solved the unusual construction problems of the Horn system with the interesting twisted bars that have been seen in the Hi-Rise for the last weeks. Jack Lindberg, John Simon and the target handling group mounted the horn components and produced an operational horn trainload. Frank Krzich and his colleagues produced a pulsed water cooling system which is but a fraction of the size of comparable systems at other laboratories. (Photo of internal piping taken by Argonne National Laboratory photographers. All others by NAL photographers, Tony Frelo and Tim Fielding.) Source: The Village Crier Vol. 5 No. 35, October 4, 1973 The collaboration of scientists found In Experiment #98 in the NAL Muon Area brings the Fermi tradition close to the Laboratory. The experimenters came from the University of Chicago (several were Fermi associates). Harvard University, Oxford University, and the University of Illinois. Before their experiment began to collect data, they posed under the magnet of the cyclotron built at the University of Chicago under Fermi's direction and moved to NAL in 1972
They are (L-R) front: L. Mo (Univ. of Chicago), S. Pordes (Harvard), H. Anderson (Chicago), R. Wilson (Harvard), I. Kirkbrlde (Oxford), W. Francis (Illinois). Second row: D. Shambroom (Harvard), T. Kirk (Illinois), R. Helsterberg (Chicago), R. Fine (Chicago), C. Wright (Chicago), F. Pipkin (Harvard), V. Bharadwaj (Oxford), H. Mails (Chicago), A. Skuja (Oxford), L. Verhey (Harvard). Back row: L. Myrianthopoulos (Chicago), A. Loomis (Harvard). Missing from photo: W. Williams, N. Booth, T. Quirk (all of Oxford). Source: The Village Crier Vol. 6 No. 17, May 2, 1974 FERMILAB SCANNERS UNCOVER SECRETS ON FILM
Glimpses of the unique regions of high energy physics explored in the Fermilab 15-Foot Bubble Chamber's first experimental runs are beginning to emerge from the Film Analysis Facility on the 9th floor of the Central Laboratory. In the hands of a group of twelve specially-skilled employees lie the clues to this vast reservoir of new knowledge. In their darkened headquarters, the scanners of the Film Analysis Facility combine their visual observations with electronic techniques to analyze film produced by the 15-Foot Chamber when two major experiments ran there, and the film of two experiments run in the 30" Bubble Chamber, in the latter half of 1974. FAF's present scanning staff consists of Karen Carew, Steve Condon, Barbara Cox, Diana Dixon-Davis, Plane Garcia, Scott Meyer, Geri Palmer, Sue Poll, Beatrice Rohde, Annette Roy, Nancy Svejda, Georgia Sykes. Ray Hanft directs the work of the Scanning Group. In the bubble chambers, each pulse of beam from the accelerator sends a shot of particles into the liquid hydrogen in the chamber. Cameras mounted in the top of the chambers photograph the interactions that occur as the beam passes through the hydrogen. About 10,000 pictures of the interactions are taken each good day of an experimental run in the 15-Foot Chamber, and nearly triple that number in the 30" Chamber. It is this film that is analyzed by the FAF. One of the major experiments in the 15-Foot Chamber (Experiment 45, a collaboration of Fermilab, Soviet visitors, and the University of Michigan), captured the first neutrino-hydrogen interactions at Fermilab energies in which every charged track can be seen and recorded by the chamber's cameras. Another experiment (Experiment 234, a collaboration of Fermilab and Florida State experimenters) produced the first hadron exposure in the Fermilab 15-Foot Chamber, demonstrating the chamber as a tool for studying the strong interaction force. The two 30" Chamber exposures also being analyzed in FAF are a study of hadron-deuteron interactions (Experiment 194 - Fermilab, Stony Brook, Carnegie-Mellon University and the University of Michigan) and the first exposure of the 30" Chamber at Fermilab to an enriched anti-proton beam (Experiment 311 - Fermilab, Michigan State University, and Oxford University). In all experiments, the permanent unbiased filmed records of the experimental results have produced enough material for months and years of study. The 15-Foot film is so rich and complex that no completely automated method can be devised to study it. The scanning procedure at Fermilab begins with the sharp observations of the scanners, as the film is run across a lighted table at the scanner's direction, magnified first at 12 times, then 66 times to examine fine details. A beginning scanner is provided a basic set of instructions - how to identify the interactions and then to record the location and a number of characteristics of the tracks. This is pure scanning, or reviewing, of the film, resembling the assembly of a library catalog of the film's contents. When the interactions have been identified, the scanner must measure the position of about ten points on each track, with a precision digitizing plane. These points are fed by the scanner into the PDP-9/L computer by tapping a foot-controlled device. Eventually, these points are analyzed by sophisticated PDP-10 programs to produce values for the momentum and direction of each track. There is nothing in any other working community that prepares a scanner for this unusual work. It is precise work, but requires flexibility and good judgment. High energy particles are supposed to do this and that, scanners are told. But if they don't, decisions must be made quickly so that an unusual interaction or an apparent exception will be pointed out to experimenters. The diversity of the interactions is so large that even after a number of years of scanning things will be seen that have never been seen before. Annette Roy, Scanning Supervisor, points out that a lively pace has been set for the scanners with the influx of work to be done on the new film from the 15-Foot Chamber. "It makes our job more involved and more interesting," she says. "The 15-Foot film takes more time and requires more scanning." Scanners' reports are studied by the scientists of the experiments. The film is shared by the institutions that collaborate in the experiment; observations are compared frequently. Meanwhile, Fermilab scanners move from one to another of the scanning assignments at Fermilab's three MOMM's and four Micrometric tables. In this variation of their work, their individual abilities assure that the high points of the films will be captured and that monotony does not set in. And what might emerge from these studies? According to Thornton Murphy, physicist currently serving as Chairman of the FAF Committee, an exciting possibility would be that Experiment 234 might find pairs of charmed particles. "If it doesn't," he says, " the detailed investigation of strange particle production at the highest energies in the world is a unique feature of the experiment. Experiment 45 is unique in that it is the one Fermilab neutrino experiment that can explore the full details of every charged track, and many of the neutral particles, in the final state of a neutrino interaction. And, naturally, they are looking for charm too - with neutrino interactions where there is a possibility of producing single charmed particles instead of pairs." It will be the careful work of the FAF scanners that will have set up these observations for Fermilab experimenters.
An example of the type of interaction being studied by Experiment 234 in the Fermilab 15-Foot Bubble Chamber
Source: The Village Crier Vol. 7 No. 11, March 13, 1975 THE ELUSIVE, WONDER-FUL NEUTRINO
Of all the objects in the universe, neutrinos are the smallest, the weakest, the most abundant, and the most elusive. Silently, invisibly, they stream down from space, flowing through your body by the trillions every second, passing onwards through the walls around you, through the bedrock of the continents, through the core of the Earth, and out the other side, as if nothing were there. They come from all directions: even at midnight, a ghostly "neutrino-shine" from the sun wells up beneath your feet just as brightly as it rains down at noon. Neutrinos are so unconcerned with our ordinary world that only the most sophisticated experiments can detect them. In fact, physicists have a tough time just describing them. They tell us that a neutrino is a type of subatomic particle, a tiny grain of matter less than a billionth of an inch across. But they also tell us that the neutrino's subatomic world is a stark and eerie place, where ordinary words like color, shape and texture have no meaning. Instead, physicists define neutrinos by what the particles do (or don't do): a neutrino is an object that carries energy, but no mass and no electric charge. It moves at the speed of light and can never stand still. It spins like a top, and can never slow down. It responds to just one kind of force, the "weak" force, which no one understands. But as bizarre and elusive as neutrinos may be, they are not magic, and they do exist. They are emitted naturally by certain radioactive elements, and by thermonuclear fusion in the core of the sun and the stars. They are also emitted from nuclear reactors as a byproduct of uranium fission. And they can be created artificially in giant particle accelerators such as the one at Fermilab. But knowing where a particle comes from -- and even being able to create it at will -- is not the same thing as understanding it. Why does the neutrino exist?, physicists are asking. What role does it play in its subatomic world, which it shares with dozens of other types of particles? And why does the neutrino do what it does? What is this thing called the weak force? In the next few years we may begin to see some answers to these questions. For the first time since the neutrino was discovered, 40 years ago, giant machines like the Fermilab accelerator are producing enough neutrinos, at high enough energy, for physicists to study them in detail. But even at Fermilab the experiments are difficult, painstaking, and often inconclusive. And in the early days it was worse: it took 25 years after the neutrino was "discovered" before anybody was able to find one. In the beginning the neutrino was a figment of the imagination, a wild guess at explaining a baffling phenomenon: radioactivity. In 1896 the French physicist Henri Becquerel had found that certain chemical elements, such as uranium, constantly radiated high-speed particles in all directions. These elements were thus "radioactive". Research during the next several decades had convinced physicists that these particles were coming from the central core of the atom, a tiny, dense kernel of matter they called the atomic nucleus. Their research had also convinced them that radioactivity was complicated; in fact they had identified three different types. The type we are concerned with involved objects called neutrons (NEW-trons. Don't confuse them with neutrinos; neutrons are the heavy, electrically neutral particles that make up about half the mass of the atomic nucleus. The other half is made up of protons, which have positive electric charge.) The physicists had discovered that neutrons in certain radioactive elements would slowly tear themselves apart, for no apparent reason. One fragment, a proton, would stay within the nucleus. Another fragment, a much lighter particle called an electron, would fly off as radiation. Clearly, some unknown force was at work. But that wasn't all. Careful measurements of the neutrons' rupture had shown that energy was disappearing. Now if there's anything dear to a physicist's heart, it is the law that says "Energy does not disappear, it is conserved." Rather than give up this law, the German physicist Wolfgang Pauli suggested in 1931 that the missing energy was being carried off by an invisible particle. Scientists are rarely inclined to believe in things they can't see. But Enrico Fermi (the Italian physicist for whom Fermilab is named) took Pauli's idea seriously, and in 1934 christened the new object with the delightful name "neutrino", which means "little neutral one" in Italian. Fermi had realized that Pauli's new particle must be deeply involved in the mysterious forces within the neutron. None of the familiar, everyday forces -gravity, electricity or magnetism -- seemed capable of tearing the neutron apart. Neither did the less familiar "strong", or "nuclear" force, which binds protons and neutrons together in the nucleus. Fermi called the unknown quantity the "weak" force, because it worked so slowly, and he wrote down a mathematical equation that described in an approximate way how neutrons, neutrinos, electrons and other particles behave when the force is acting. With some changes, this equation is a useful guide for neutrino physicists today. Thus, the neutrino was "discovered" in the 1930's. But nobody had ever really seen one, and until somebody did, not even Fermi could be sure that neutrinos were real. The problem was, and is, the weak force itself. It's so very weak, and so very slow, that a neutrino tends to fly right through ordinary matter before the force has a chance to do anything to stop it. And if the weak force doesn't catch it then nothing will, because a neutrino ignores everything else.
A schematic of the Neutrino Line at Fermilab where neutrinos are generated indirectly from protons. Protons from the accelerator strike a metal target, generating pions and kaons which then decay mainly into muons, neutrinos and antineutrinos. Muons and any remaining hadrons are filtered out as they pass through the mound of earth (muon shield); At the end of this process only neutrinos and anti-neutrinos remain. Detectors such as the 15-ft. Bubble Chamber and the equipment of other neutrino experiments are placed at this point to record neutrino activity in its purest form.
The experimental apparatus of Experiment #310 in Lab C of the Fermilab Neutrino Area. Neutrino beam enters from the right. Interactions are detected in the large scintillator tanks at right and in the circular magnets at left. So try to catch one. Try to put it in a box. How? The thing will sail right out of the box, right through the Earth itself, and never even notice. Or... almost never. Suppose you take a big enough mass -- say a huge tank of water -put it where a lot of neutrinos will pass through, and wait. If you wait long enough, there's a tiny chance that the weak forces in one or two of the water molecules might be able to catch a neutrino before it quite gets away. Two very patient physicists did just this experiment in 1956. Fredrick Reines and Clyde L. Cowan placed their tank outside a nuclear reactor at the Atomic Energy Commission's Savannah River Plant, near Augusta, Georgia. Using Fermi's equation they had estimated that the uranium fission inside the reactor should be emitting about a quadrillion neutrinos per second. And they were right: once or twice an hour a water molecule would in fact catch a neutrino -- and the jolt of energy would blow it apart. The submicroscopic fragments of that collision would then fly off through the water, triggering automatic detectors and giving Reines and Cowan proof -- indirect, but undeniable -- that neutrinos were real. But there's always a question about this kind of abstract science: "so what?" In this case, so what if neutrinos are real? We can't see them, or hear them, or touch them, and they ignore us so thoroughly that it doesn't seem to make much difference to us if they exist or not. Well, it's true that neutrinos aren't particularly relevant to our everyday affairs. But take a larger view. For example how might neutrinos affect the ultimate fate of the universe? Right now, the universe is expanding: astronomers believe that all the stars and galaxies are fragments of a single vast explosion -- the "Big Bang" -- which created the universe some 20 billion years ago. Many astronomers also believe that the universe will keep on expanding forever, until all the galaxies have receded to infinity and the night sky is empty. But what about neutrinos? The universe is awash with neutrinos. They gush forth from every star in the sky, including the sun, unimaginable numbers of neutrinos created by thermonuclear fusion at each star's core. Still other neutrinos have been sailing among the galaxies for 20 billion years, ever since they were created in the Big Bang itself. All these neutrinos are invisible, of course, so no one knows exactly how many of them there are. But invisible or not, they have energy. And Prof. Einstein has assured us that this causes them to exert a gravitational pull on everything else in the universe. If there are enough of them, say astronomers, then billions of years from now their combined gravitation could slow the expanding universe to a halt, and pull it back in on itself -- stars, planets, galaxies, and neutrinos, all collapsing together in a fiery reversal of the original Big Bang. This is pretty heady stuff, but neutrinos also play a vital role in slightly less cosmic matters -- the birth, life and death of stars, for example. In fact, they seem to be a key for our full understanding of how the universe works -- which makes it all the more frustrating that we really don't know very much about them. It's not for lack of trying. In the 20 years since Reines and Cowan's experiment, and especially in the last five years, physicists have been collecting data about neutrinos and the weak interactions in every way they can. But the harder they've looked, the harder they've tried to reduce all these facts to a simple pattern, the more complicated it's all become. In 1962, for example, a second type of neutrino was discovered, identical to the first in every way but one. That one way shows up only on those rare occasions that the neutrinos interact with another particle. Ever since Fermi wrote down his equation, physicists have known that the (original) neutrino interacts by grabbing off some negative electric charge with the weak force -- and turning itself into a negatively charged electron. In the same situation, the second type of neutrino grabs some negative charge and turns itself into a muon (MEW-on), a particle that's exactly like the electron except that it's heavier. Now what kind of pattern is this? Nobody understands the first neutrino/electron pair, yet here is this second set that's just the same, but different! What's the second set for? Is nature just being redundant? Or are there even more sets we haven't discovered yet, with more neutrinos and even heavier versions of the electron and muon? And what's this business of "grabbing charge", and turning into something else? When a cue ball hits an 8-ball it just bounces off; it doesn't change into a watermelon. Don't either of the neutrinos ever just bounce off other particles? On the other hand, maybe nature is trying to tell us something here. There is clearly a connection between the weak force and electric charge. Does this mean that electricity and the weak force are really just two faces of the same force? (For mathematical reasons, such a force would also have to include a third face: magnetism.) There are also connections between the weak force and the strong forces within the nucleus. Could this mean that all four -- electricity, magnetism, strong force and weak force are parts of a single, underlying unity? The physicists who designed Fermilab in the 1960's had these questions very much in mind. Their basic idea was much the same as that of the Savannah River experiment: fire an intense beam of high-energy neutrinos through a massive target and watch for the rare neutrino interactions. If the physicists were lucky enough, and clever enough, they might be able to learn something from the collision fragments about the weak force, the neutrino, and -- as a bonus -- about how the target particles themselves are put together. Crude? Yes. One physicist says the process is like trying to learn how a wristwatch works by hanging it from a tree, shooting BB's at it, and watching how they bounce off. But crude as the process is, it works. Physicists have been firing protons and electrons at target particles since the 1930's. Among the collision fragments they've discovered a whole zoo full of exotic, unstable particles (in addition to the electron, muon and their neutrinos), and they've learned a lot about how these particles behave.
And ever since Reines and Cowan's experiment, they've also been trying to develop a useful beam of neutrinos. Most high energy laboratories around the world now have neutrino beams. Fermilab now produces more neutrinos, at higher energies, than any other accelerator in the world. It makes the neutrinos indirectly. Every 10 seconds about twenty thousand billion protons, accelerated to virtually the speed of light, slam into a block of steel. Out the back bursts a spray of every imaginable particle -including about a billion muon-type neutrinos. This spray then passes into a one half mile mound of dirt, which stops most particles dead. Only the neutrinos make it through to the targets in the experimental area. One of the most successful experiments there, and a good illustration of them all, is E-310.* This experiment is actually a modification and expansion of an earlier experiment, E1A, which began taking data in early 1973. E-310 is operated by physicists from Fermilab, Harvard, the University of Pennsylvania, Rutgers University, and the University of Wisconsin. The experiment itself consists of 150 tons of target and a line of four circular 24-foot magnets standing on edge. The whole thing is wired with sophisticated electronics and is connected to computers. When the experiment is in operation a billion neutrinos pass through the target with every pulse of the accelerator. About once per minute, one of them interacts with a proton or neutron in the target, transforms itself into a muon, and blasts loose a shower of charged particles. Some of this burst of energy passes through the liquid scintillator causing it to glow and alert electronic detectors. A series of "spark chambers" then automatically discharges, tracing each particle's path with a trail of bright pink sparks. Behind the target, more spark chambers track the muon, while the magnets bend and twist its path to measure its energy. In the end, a few billionths of a second after its creation, the muon is lost into the walls of the building. The data are recorded in a computer, and E-310 waits for the next burst of neutrinos. Meanwhile, the physicists involved in the experiment also wait. Their job will come later, when they evaluate the data, and try to reconstruct what has happened in each event. "Nobody runs down the street shouting 'Eureka' in neutrino work," says University of Wisconsin physicist Don Reeder. "It's more painful than that. The data come in very slowly, and you have to extrapolate from statistically poor information." "Maybe you find something exciting," he says, "but you don't want to base something startling and new on just two events. So you go back and change the experiment. Then you get new results, and maybe they aren't the same, so you have to re-interpret those. You go through several manic-depressive cycles before you're sure." However arduous the physicists' job may be, they've managed to compile over 10,000 neutrino events since E-310 began operation as E1A. (Less than 100 total had ever been seen before Fermilab.) This mass of data has led to two major discoveries. First, neutrinos can indeed bounce off other particles without grabbing away their charge. (Or, in physicist's jargon, "neutral currents" exist.) This discovery was announced at Fermilab in the summer of 1973. Second, new types of particles exist with the property known as charm. In recent years, charmed particles have been found in many different experiments. But E1A's evidence, while indirect (in about 100 cases the magnets found two neutrinos instead of just one), was the first. Meanwhile, in other neutrino experiments at Fermilab and at other institutions around the world, new discoveries are coming in rapidly. What do these discoveries mean? Perhaps they don't seem very exciting by themselves. But that's the point: they are not by themselves, they are part of a pattern. Scientific research has often been compared to putting together a puzzle. That's a good analogy. But remember, for this puzzle there's no picture on the box-top. No one is even sure how many pieces there are, or if the pieces they've already got are assembled correctly. So particle physicists, like all scientists, gather their new pieces of data slowly and carefully. Then they put them together in different combinations, trying as best they can to guess the overall pattern. Individual facts, like individual pieces of a puzzle, may or may not be interesting in themselves; their real importance comes when they advance our knowledge of the pattern of nature. So it is with neutral currents and charmed particles. In the last few years a new pattern has been emerging. New types of mathematical equations have been developed that promise to give us at last a unified theory of forces and particles. The theory -- which claims that the known particles are built out of unseen objects called quarks and gluons, which have marvelous properties like isospin, hypercharge, strangeness, and charm -- is far from its final form. But even so, physicists today share a mood of jubilation and excitement like nothing in recent memory, because two crucial bits of evidence for this theory, two absolutely essential pieces of the puzzle -- are first, the existence of neutral currents, and second, the existence of charmed particles. The discovery of these two phenomena has fired in particle physicists the feeling that a revolution in scientific understanding may be very close. The new science of particles is still dim and hazy, but the mists are clearing very rapidly. And when the scientific history of this revolution is written, it will surely show that Fermilab and the Fermilab neutrinos played a vital role. *Spokesmen for E-310 described this experiment and experimental results in an article in Scientific American Magazine, January, 1976, p.44, "The Search for New Families of Elementary Particles." Click here to return to article. NOTE: Professor A.K. Mann, one of the collaborators on Experiment #310 mentioned in the article above, delivered a Sigma Xi lecture at Fermilab on Tuesday, January 25, 1977, at 8 p.m. in the Auditorium. Dr. Mann's lecture was titled, "Exploring the Universe with a Neutrino Microscope." He described the universal implications of the research which his group conducted at Fermilab. Source: The Village Crier Vol. 9 No. 3, January 20, 1977 BIONIC ARMS SALVAGE NEUTRINO TRAIN
"Bionic" arms, Fermilab's version, are helping salvage a train "wreck" in the Neutrino Area. The arms are servo-manipulators, electromechanical creations that perform the functions of arms, hands and fingers with human direction. Fermilab Neutrino engineers are employing the bionic arms to clean up a disabled neutrino target train. A modified mine locomotive hauls beam line equipment into the target tube on narrow-gauge (30 in.) tracks laid in the complex--including the target tube, target hall (Neuhall) and target service building. According to Jack Lindberg, associate mechanical group leader, the salvage story started in December. The Proton Area went into standby Dec. 20 to allow high intensity beam running to the Neutrino Area. During the morning of Wednesday, Dec. 29, all beam was shut off to the Neutrino Area--three experiments reported 80-90 percent decrease in triggers, E310, E482 and E460. "Something in the beam," Shigeki Mori, mechanical group leader said, "was stopping secondary particles which decay into neutrinos. Everybody was puzzled; no one knew what the problem was." They found out by looking into the target tube with a 60X telescope. The view revealed that an eight-foot long steel collimator--a device for collimating secondary particles-had been heated to about 1500°F by the particles during the high intensity run. As a result, the assembly of a series of two-inch steel slabs, measuring 6 x 6 inches, had begun to soften. When it couldn't support its own weight, the collimator sagged into the beam, becoming a sponge for neutrinos. Richard Lundy, associate section leader, credited the collimator with nobly doing its job of protecting the downstream magnet. Only shreds remained of the collimator's aluminum cover. No one expected secondary particles to deposit that much thermal energy, and as a result the area received significant radiation contamination, requiring a four-day cleanup project conducted by Radiation Physics personnel. Fred Gardner, radiation safety officer supervised procedures. Repairs got underway after New Year's. The disabled triplet was pulled from the target tube and stored for reconstruction. A horn train was inserted in mid-January. Rejuvenation of the triplet, due to high radioactivity of the equipment, was done remotely in the target service building. Enter Fermilab's bionic arms! "Main purpose of the system," John Simon, remote systems engineer said, "is to minimize, if not totally eliminate, radiation exposure to personnel." Argonne Mark IV Electric Master-Slave Manipulator Installation is the technical name. It, and a 20-ton crane, are mounted on separate overhead bridges and operate on the same set of rails. Two closed-circuit TV cameras, equipped with zoom lenses and pan and tilt supports, are mounted at opposite corners of the building. The manipulators were prototypes developed by the Remote Control Division of Argonne National Laboratory. Except for modernization of transistor servo-amplifiers, they are original equipment. The manipulator unit consists of a pair of slave servo-manipulator arms mounted on a bridge, carriage and rotating turret. The arms move five feet, on a vertical post. They can reach about 85 percent of the floor area from the floor to about 10 feet high and approach most work from any angle. The unit's eyes are two high-resolution TV cameras mounted under the body of the right-hand manipulator slave. One camera, with a zoom lens, provides a detail magnified view; the other, with a wide-angle lens, covers the entire area reached by the arms. A third TV camera, mounted facing down, gives a plan view of the tongs and operating area. By late March work had progressed to the point where partial manual methods could be substituted. The repair unit's objective is to have the train completely revitalized by June, with help from Fermilab's "bionic arms." Source: The Village Crier Vol. 9 No. 13, March 31, 1977 Prof. A.K. Mann, who heads Experiment #310 in the Neutrino Area, had high praise for the Fermilab accelerator when asked recently about progress on his experiment. "In 2-1/2 weeks we have received as many protons on the neutrino target as we did in 2-1/2 years of running our previous experiment, #1-A." Mann went on to point out that beam intensity per pulse for use by the experimenters is now a factor of ten better than two years ago, and "besides that, the overall stability of operation is several times better." The E-310 group is studying neutrinos and the weak force involved in neutrino interactions. Russ Huson, head of the Accelerator Division, replies, "Yes, it's true that some of the hard work we have been putting into making multitudes of minor improvements to the accelerator over the past few years now seems to be paying off. Naturally, we still have our bad days from time to time, but we are usually able to run for quite reasonable lengths of time with few interruptions." Russ has been emphasizing to the staff of the Accelerator Division for some time that though there may not be as much excitement in running a whole shift without a break as there is to a sudden dramatic increase in intensity, to an experimenter the uninterrupted running is more important. A sudden interruption of the accelerator running may mean that the experiment will have to repeat or re-evaluate its data. "The fight for reliability is one in which we must be involved constantly," says Huson. "It is gratifying to have our victories noticed and appreciated by the experimenters." Source: The Village Crier Vol. 9 No. 25, June 30, 1977 GEODESIC DOME AT LAB A RECEIVES COPPER FACE LIFT
by John Paulk Remember the multi-colored geodesic dome - the most prominent feature of the Neutrino beam line? Well, it's still there but it has been clad in copper sheeting. The reason for the rehabilitation was because of bad leaks between the panels and the structural grid. Another problem was unsightly color fading of the fiberglass panels due to exposure to the sun's ultraviolet rays. Several alternatives were carefully examined before selecting copper sheeting. They included an entire new roof system, replacement of aluminum-coated panels, prefabricated clear glass panels, sprayed-on urethane coating, a single-ply membrane covering and terne metal sheathing. Of all of these, copper was economical and judged to be the best choice. It virtually assured no leaks indefinitely and it could be fabricated in place by a local firm. As the copper weathers, a green oxidation film will form. Source: FermiNews, December 16, 1982 Internal Target Meson Area Proton Area |
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