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Beamline U4B

General Information

Source Type
Bending Magnet

Status
Operational

General User Beamtime
60%

Energy Range
20-1200 eV

Beamline Type
Facility Beamline

Technique(s)
X-ray reflectivity
X-ray scattering, magnetic
X-ray scattering, resonant
Magnetic circular dichroism
X-ray absorption spectroscopy
X-ray fluorescence spectroscopy

Institution(s)
Montana State University

Research Types
Soft x-ray and VUV photo absorption spectroscopy. Techniques: X-ray absorption spectroscopy, X-ray magnetic circular dichroism, X-ray fluorescence spectroscopy, x-ray resonant magnetic and/or non-magnetic scattering.

Contact Information

Spokesperson The person from each beamline who acts as a contact point between the beamline management and NSLS administration. Contact for questions about the beamline scientific program, experimental capabilities, and beamline management.
Dario Arena, Brookhaven National Laboratory, darena@bnl.gov, 344-5303
Yves Idzerda, Montana State University, Idzerda@physics.montana.edu, 406-994-7838

Local Contact The beamline staff member who is typically responsible for overseeing the daily operation and maintenance of the beamline. Contact for questions about beamline instrumentation, experimental details, and training.
Dario Arena, Brookhaven National Laboratory, darena@bnl.gov, 344-5303
Joseph Dvorak, Brookhaven National Laboratory, jdvorak@bnl.gov, 344-5135

Beamtime Scheduler The beamline staff member responsible for coordination of beamline schedule every trimester. Contact for questions about beamtime scheduling.
Dario Arena, Brookhaven National Laboratory, darena@bnl.gov, 344-5303

Beamline Phone
631-344-7290

Instrumentation

Beamline Characteristics

Energy Range Mono Crystal or Grating Resolution (ΔE/E) Flux Spot Size (mm) Total Angular Acceptance (mrad)
68 – 300 300 lines/mm 10-4 - 10-3 2 x 1011 ph/sec/0.1%bw (@ 500 mA)   15.0H x 1.5V
136 – 600 600 lines/mm 10-4 - 10-3 1 x 1011 ph/sec/0.1%bw (@ 500 mA)   15.0H x 1.5V
272 – 1200 1200 lines/mm 10-4 - 10-3 1 x 1011 ph/sec/0.1%bw (@ 500 mA)   15.0H x 1.5V
13 – 50 600 lines/mm 10-4 - 10-3 1 x 1011 ph/sec/0.1%bw (@ 500 mA)   15.0H x 1.5V
25 – 120 1200 lines/mm 10-4 - 10-3 1 x 1011 ph/sec/0.1%bw (@ 500 mA)   15.0H x 1.5V

Source Type
Bending magnet

Optical System
Horizontal Focusing Mirror (HFM): Spherical platinum-coated Zerodur mirror; focuses source horizontally at the sample position (14.8 meters from source); angle of incidence is 87 degrees; located 3.2 meters from the source.

Vertically Focusing Mirror (VFM): Spherical platinum-coated Zerodur mirror; focuses the source vertically onto the entrance slit of the monochromator (located 2.5 meters downstream of VFM); angle of incidence is 87.5 degrees; located 3.84 meters from the source. This mirror can be raised above or lowered below the orbital plane to select right- or left-handed elliptical polarization, for Magnetic Circular Dichroism (MCD) experiments.

Gratings: Three soft x-ray spherical gratings made of single-crystal silicon coated with gold; ruling densities 300, 600, and 1200 lines/mm, laminar type, holographically ruled and ion etched; diffract and focus vertically onto the moveable exit slit of the monochromator; the wavelength scanning mechanism is a simple sine drive type; zero order angle of incidence is 87 degrees (included angle is 174 degrees). Two VUV gratings made of ULE glass, coated with gold; ruling densities 600 and 1200 lines/mm, laminar type, holographically ruled and ion etched; diffract and focus vertically onto the movable exit slit of the monochromator via two gold-coated plane mirrors, at 12 degrees and 5 degrees grazing angles of incidence; zero order angle of incidence is 80 degrees (included angle is 160 degrees). Grating chamber is located 10.6 meters from the source.

The spot size at the first experimental chamber, located ~2 m downstream of the exit slit, is 1.5(v) x 10(h) mm2 (Can be collimated down). A second experimental chamber, for soft x-ray reflectivity, is located ~2 m downstream of the first experimental chamber, with a spot size of ~2.5 x 12 mm2.

Refocusing Optics: Bent elliptical "toroid" gold-coated electroless-nickel-on-aluminum mirror; focuses the first sample position (14.8 meters from source) to the thirdsample position (20.8 meters from source) with spot size of approx. 0.25(V) x 1.0(H) mm2.

Experimental Apparatus
First experimental chamber: general purpose UHV chamber with sample preparation/loading and liquid Helium capable cryostat for high resolution absorption or total electron yield measurements on solid samples. Switchable electromagnet for Magnetic Circular Dichroism (MCD) and hysteresis measurements. Maximum magnetic field (pulsed) is approximately 1000 Oe.

Second experimental chamber: soft x-ray reflectometer; sample preparation/loading and liquid nitrogen cryostat. Maximum magnetic field is approximately 300 Oe.

Third experimental chamber: available for roll-on/roll-off experimental chambers.

Computer System Hardware & Software
Windows 2000 PC; custom written software for data acquisition.

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