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Beamline U4A

General Information

Source Type
Bending Magnet

Status
Diagnostic and Instrumentation

General User Beamtime
0%

Energy Range Category
Ultraviolet

Energy Range
10-250 eV

Beamline Type
Participating Research Team (PRT)

Technique(s)
Ultraviolet photoelectron spectroscopy

Research Types
Photoemission spectroscopy in the study of electronic structures in solids and on surfaces.

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.
Joseph Dvorak, Brookhaven National Laboratory, jdvorak@bnl.gov, 344-5135

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.
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.

Beamline Phone
631-344-5504

Instrumentation

Beamline Characteristics

Energy Range Mono Crystal or Grating Resolution (ΔE/E) Flux Spot Size (mm) Total Angular Acceptance (mrad)
10 – 80 300 lines/mm 2 x 10-4 4 x 1010 ph/sec/0.1%bw (@ 500 mA) 2.0H x 0.5V 22.5H x 6.0V
30 – 140 900 lines/mm 2 x 10-4 4 x 1010 ph/sec/0.1%bw (@ 500 mA) 2.0H x 0.5V 22.5H x 6.0V
80 – 300 1800 lines/mm 2 x 10-4 1 x 1010 ph/sec/0.1%bw (@ 500 mA) 2.0H x 0.5V 22.5H x 6.0V

Source Type
Bending magnet

Optical System
Mirror 1: Gold-coated glass toroidal mirror (M0), 4.325 degree grazing angle of incidence, 22.5 mrad horizontal collection angle, focuses at sample position in upstream endstation. Located 2.1 meters from source.

Monochromator: Spherical Grating Monochromator (SGM), with 162 degree included angle, 2 m entrance armlength, and 4.0-4.4 m (variable) exit armlength. The entrance slit is located 2.45 m downstream of the M0 mirror. The three spherical gold-coated ULE gratings listed in the table above are interchangeable in UHV, and an exit slit. The exit slit (in its maximum downstream position) is located 11 meters from source. The upstream endstation is located ~0.1 m downstream of the exit slit bench.

Mirror 2: Refocusing mirror: gold-coated glass toroid, at 4.675 degree grazing angle of incidence, providing horizontal and vertical focusing of beam. Located 1.8 meters downstream of the exit slit, demagnifies 3:1 on the sample position in the downstream endstation, 0.6 m downstream of this mirror.

Experimental Apparatus
Upstream endstation: Ultra-high vacuum sample chamber configured for high-resolution angle-integrated photoemission, surface sample preparation (via separate preparation chamber with load-lock capability) and characterization.

Downstream endstation: Ultra-high vacuum sample chamber configured for angle-resolved photoemission, surface sample preparation and characterization.

Computer System Hardware & Software
Hardware: Dell Personal Computer (circa 2003) with National Instruments GPIB and IoTech DaqBoard2000 (A/D, D/A, digital I/O, scalars and timers) interface boards.

Operating System: Red Hat Linux 9.0.

Acquisition Software: Customized software written in C by the PRT. Data stored as text and postscript files.

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