2.
RADIO FREQUENCY (RF) DEVICES AND COMPONENTS FOR ACCELERATOR FACILITIES
The Office of Basic Energy
Sciences, within the DOE’s Office of Science, is
responsible for current and future synchrotron radiation light source, free
electron lasers, and spallation neutron source user
facilities. This topic seeks the
development of radio frequency devices and components to support these user
facilities. Grant applications are
sought only in the following subtopics.
a. Power Devices and Components for
High Level Radio Frequency (RF)
Accelerator Systems—Grant
applications are sought to develop higher order mode (HOM) inductive output
tube (IOT) continuous wave (CW) amplifiers at 350 MHz (tunable over a
reasonable range would be desirable) at two power levels: 1 MW CW (applicable
to the case where one amplifier drives several cavities) and 200 kW CW (in the
case where each cavity has its own amplifier). Such a device could provide
lower operating voltage, smaller size, and lower operating cost (approximately
15-20% higher efficiency over current klystrons). The potential energy cost
savings with an IOT that could operate at ~70% efficiency (television IOTs approach that now with depressed collectors) would be
significant. Making the IOTs tunable over a
reasonable range also would be a desirable feature.
Grant
applications also are sought to develop (1) pulsed inductive output tube (IOT)
amplifier at 402.5 MHz, 140 kW, 10% duty factor for low-energy bunching
application for high power H-/proton beams; (2) higher power Insulated Gate
Bipolar Transistor (IGBT) technology. IGBTs with >
6000Volts, >2000Amps are required for development of high power modulators
and power supplies; (3) a high-efficiency-switching high-voltage power supply
for next generation RF accelerator systems, which will need cleaner HV DC power
on RF amplifier devices, in order to create less phase and amplitude jitter on
the RF output (regulation of line power ripple must be achieved at the 0.5%
level); (4) a 2.815GHz CW klystron (~100kW), possibly with two output
windows, that would be suitable for a superconducting (SC) rf
cavity; (5)a moderate power (10-50kW CW) tetrode
cavity, tunable from 340-360MHz (or possibly more) – such a cavity would make tetrodes or diacrodes competitive
for sockets in SC cavity applications; (6) a very high power (100-400 kW) 350-500
MHz solid state power amplifier to replace klystron amplifiers in synchrotron
light sources; (7) a variable input coupler for normal conducting (NC) and
superconducting (SC) RF cavities – approaches must demonstrate a significant
increase in mechanical complexity compared with fixed coupler designs, and
provide for adjustments of the input coupler beta in situ,
in order to optimize the RF system efficiency; (8) a high power fundamental
power coupler (FPC) for ERL injector cavities with the following
specifications: 1408 MHz operating frequency, average RF power up to 200 kW in
traveling waver (TW) mode, nominal external Q of 5 x 104, and
factor-of-10 variable coupling with minimum transverse kick to the beam; and
(9) an adjustable 20-way 40 kW CW power combiner operating at 352 MHz..
Questions - contact Roger Klaffky (roger.klaffky@science.doe.gov)
b. Modulators for High Level Radio Frequency (RF)
Accelerator Systems—Grant
applications are sought to develop a
high-level amplitude and phase modulator (in either waveguide or
coaxial topology) that can demonstrate modulation ability out to 20 kHz. Significant cost savings could be achieved if
one klystron were used to drive multiple accelerating cavities, while retaining
phase and amplitude control at the individual cavity level. Grant applications also are sought to develop
(1) a 1KHz. 300 kV, 300A solid-state modulator for production of picosecond X-ray pulses using RF deflecting cavities; and
(2) a robust, high-average-power (200kW) 1kHz modulator system that operates at
about 300 kV, 300 A with ultimate rep rate at 1kHz or higher.
Questions - contact Roger Klaffky (roger.klaffky@science.doe.gov
c. Low Level Radio Frequency (LLRF) Accelerator
Systems—Grant applications are sought to develop an RF phase
detector that can provide accurate measurements of phase jitter down to 0.01°,
which is needed at several accelerator facilities (e.g., the Linear Coherent
Light Source and for future ultra short x-ray capabilities at the Advanced
Photon Source) and can provide an independent accurate measurement of the LLRF
control performance. When the accelerator
beam itself is used to determine RF system performance, facility commissioning
is difficult.
Grant
applications also are sought to develop digital, low-level RF systems to
control the phase and amplitude of superconducting RF cavities operating at 476
MHz, with loaded Q-values in the range of 108. Of particular interest are systems capable of
phase control.
Finally,
grant applications are sought to develop a user-friendly, multi-channel
"all in one" time-stamp diagnostic instrument that can accept
baseband RF signals out to 3 GHz, as well as DC signals, for analysis of RF
accelerator system fault events.
Accurate and timely fault analysis is necessary for present and future
user facilities to operate at a very high level of reliability, and an "all-in-one"
box would be more efficient than using several individual scopes.
Questions - contact Roger Klaffky (roger.klaffky@science.doe.gov)
d. Devices for the Manipulation of
Electron Beams—Grant applications also are sought to
develop devices for the manipulation of electron beams in storage rings and
linear accelerators. Such devices are
used to facilitate deflection of the beam onto a predicted trajectory or to
generate a time-space correlation in the beam.
For example, electromagnetic (RF) cavities operating in a dipole mode
could introduce a transverse kick to an electron bunch as a whole or provide a
“head-tail” displacement within the bunch.
Such cavities would need to provide deflecting kick voltages up 10 MV,
with phase error < 0.01° and amplitude error <10-4, with
parasitic modes damped to Q-values <1000 and with minimal short-range wakefields.
Questions - contact Roger Klaffky (roger.klaffky@science.doe.gov)
Subtopic a References:
1. Proceedings of Fourth CW and High
Average Power RF Workshop, Argonne National Laboratory, Argonne, IL, May 1-4,
2006 . (Abstracts and presentation slides available at:
(http://www.aps.anl.gov/News/Conferences/2006/CWHAP06/index.html)
Subtopic b References:
1.
Proceedings of Fourth CW and High Average Power RF Workshop, Argonne
National Laboratory, Argonne, IL, May 1-4, 2006 . (Abstracts and presentation
slides available at:
(http://www.aps.anl.gov/News/Conferences/2006/CWHAP06/index.html)
Subtopic c References:
1.
Proceedings of Low Level RF (Radio Frequency) Workshop, CERN, October
2005. (Abstracts and presentation slides available at: http://ab-ws-llrf05.web.cern.ch/ab-ws-llrf05/.
On menu at left, click on “Conference programme and
registration” and then on author index. Click on titles next to authors’ names
to view abstracts. For slides, click on “slides”.)
Subtopic d References:
1. A. Zholents, P. Heimann, M. Zolotorev, and J. Byrd, Nucl. Instrum. Methods Phys. Res., Sect. A 425, 385 (1999).
2. Crab cavity development, K. Hosoyama et al, http://www.lns.cornell.edu/public/SRF2005/pdfs/ThA09.pdf
3. Simulation and analysis of using deflecting cavities to produce short x-ray pulses
with the Advanced Photon Source, M. Borland, PRST-AB 8, 074001 (2005)