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Beamline U3C

General Information

Source Type
Bending Magnet

Status
Operational

General User Beamtime
25%

Energy Range Category
Soft X-Ray (0.1-1 keV)

Energy Range
50-1000 eV

Beamline Type
Participating Research Team (PRT)

Technique(s)
Metrology

Institution(s)
Lawrence Livermore National Laboratory
Los Alamos National Laboratory
National Security Technologies
Sandia National Laboratories

Research Types
Soft x-ray instrument and detector development and calibration

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.
Kenneth Moy, National Security Technologies, moykj@nv.doe.gov, 805/681-2284

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.
Bin Dong, SFA, Inc., bdong01@bnl.gov, 6313447015

Beamtime Scheduler The beamline staff member responsible for coordination of beamline schedule every trimester. Contact for questions about beamtime scheduling.
Bin Dong, SFA, Inc., bdong01@bnl.gov, 6313447015

Beamline Phone
631-344-5503

Instrumentation

Beamline Characteristics

Energy Range Mono Crystal or Grating Resolution (ΔE/E) Flux Spot Size (mm) Total Angular Acceptance (mrad)
50 – 320 eV 1200 lines/mm <0.9 eV @110 eV 5 x 109 ph/sec (@150 eV) 1 10H x <1V 10
200 – 1600 eV 1200 lines/mm <1.5 eV @450 eV 7 x 108 ph/sec (@400 eV) 2 10H x <1V 10
285 – 1600 eV 1200 lines/mm not available not available 10H x <1V 10

1. Flux measured thru a 1/16 inch aperture with 0.03 micron Ti and 1 micron B filters (20% combined transmission), quadruple reflection from 4 degree rhodium mirrors (30% transmission), and 50 micron monochromator slits.
2. Flux measured thru a 1/16 inch aperture with a 0.6 micron Ti filter (32% combined transmission), quadruple reflection from 2.5 degree vanadium mirrors (9% transmission), and 50 micron monochromator slits.

Source Type
Bending magnet

Optical System
Mirror: A platinum-coated bent float glass mirror (M0) with 2 degree incidence angle, 3.3 m from the source, provides horizontal focusing at the monochromator exit slit with 1:1 magnification.

Monochromator: The extended range grasshopper (ERG) monochromator employs a Rowland circle geometry with fixed exit slit position and exit beam angle. A bent, gold-coated mirror (M1) with 1 degree incidence angle focuses onto a gold-coated Codling mirror (M2) entrance slit with 7:1 demagnification. The Codling mirror reflects the beam onto a gold coated spherical grating on the Rowland circle, with a fixed grazing incidence angle of 2 degrees.

A gold coated bent cylindrical mirror (M3), 7.5 m from the source, provides refocusing of the beam from the exit slit. The incidence angle for this mirror is set to produce a < 1 mm vertical spot size and horizontal fan of approximately 1 cm at the end station, and accommodate a 1.3 m differential pumping station which includes x-ray material filters and order sorter for ensuring beam purity in the range of 95-99%.

Filter wheels and order sorter (HOT): To reduce the contamination from scattered light and high order harmonics two filter wheels with 11 filters each are available for inserting up to two filters at a time into the beam. The operation of the filter wheels is integrated into the beam line control software so that the correct filters for any given photon energy can be inserted automatically. The filters alone provide beam purities of approximately 80-97%, depending on the photon energy. To further reduce harmonic contamination an order sorter from Hettrick Scientific employs quadruple reflection from 4 mirrors in a geometry which leaves the exit beam colinear with the incident beam. Six separate sets of (4) mirrors in the order sorter have coating materials and incidence angles optimized for harmonic rejection in six overlapping energy ranges between 50 eV and approximately 500 eV. The six mirror assemblies are mounted on a motorized translation drive, enabling the order sorter operation to be integrated into the beam line control software in the same manner as the filter wheels. The order sorter generally reduces the total beam contamination below the carbon edge to a fraction of a percent.

Experimental Apparatus
Lift Table: Full 6-motor alignment capability. Software control for vertical alignment.

"Standard" End Station: Selectable pinhole apertures from 1/8" to 1/128" size. Calibrated monitor diode. "Back" diode for transmission measurements. Calibrated Keithley electrometers for diode/detector signal measurement. Detector/Filter "stalk" ("Standard" detector holder (6 positions) with vacuum feedthroughs; "Standard" filter holder (5 positions)). Endstation isolation valve; vent and pump capability. Software for scanning and data collection.

Other setups require: Full interlocks for all vacuum valves (if extensions are used, contiguous valveless vacuum with endstation is preferred). Vacuum tight to 10-6 Torr or lower. For details on holders please consult beamline staff.

Computer System Hardware & Software
The beamline is operated from a 1.8 GHz Pentium Dell PC with Windows XP OS, LabVIEW beamline control software, and serial, GPIB, and PCI-PXI MXI-3 communications interfaces. The ERG monochromator motors are controlled with a 'Stotts box' indexer/driver through a PXI 8420/4 serial interface. The Heidenhain LS703 linear encoder for the ERG carriage is interfaced to an IG604 CAMAC register and read via a CC-488 GPIB CAMAC crate controller. Both filter wheels are controlled with Compumotor 2100 indexers thru GPIB, and the order sorter is controlled with a Compumotor Zeta6104 controller thru a direct serial link to the PC. The beamline software is designed to interface readily with experimental data acquisition and control programs written in LabVIEW, enabling programmatic control of the ERG, filter wheels, and order sorter from within such programs.

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