BL15-2

Overview
15-2

High Resolution X-ray Spectroscopy

Beamline 15-2 is an undulator experimental station dedicated to advanced hard x-ray spectroscopy. The end station is equipped with sub-corehole lifetime resolution x-ray emission spectrometers (a 7-crystal Johann spectrometer and a 8 crystal von Hamos instrument) as well as a high-throughput and high energy resolution (0.3eV) 40-crystal low-q x-ray Raman spectrometer. The end-station also incorporates a high-power MHz repetition laser together with fast diodes and FPGA electronics enabling laser pump x-ray probe time-resolved spectroscopies (~75ps time resolution) using the camshaft bunch (~20mA) of SPEAR3. Advanced sample environments including electrochemical cells, thermal catalysis reactors, cryostats, continuous flow liquid jets, microfluidic mixers and other in situ environments enable a multipurpose scientific program across catalysis, energy science, biochemistry, environmental science as well as actinides research.

Sample Environment —

Ambient pressure experiments, He chamber(s), flexibility with various in-situ setups including electrochemical cells and thermal reactors for operando catalysis, liquid samples and liquid jets, high pressure. Dedicated LHe cryostat (4-200 K).
Minimum sample requirement (in terms of concentration): Typically, end-station can measure sub-100umol concentrations and sub monolayer materials. Feasibility depends strongly on the technique and the scientific question. Please contact responsible scientific staff for guidance.

Instrumentation —

Detectors Multiple single element Vortex solid-state; PIPS diodes, APD diodes, ionization chambers, Pilatus, and Eiger-X.
Cryostat Oxford LHe cryostat (4-200 K)
Other Integrated fast shutter system and variable filters to alleviate radiation damage. High power and high rep rate laser: Amplitude Tangerine 50W Colby time-delay unit Teledyne Wavemaster 816ZI-B oscilloscope 16 GHz, 80 GS/s) Teledyne ADQ-14bit 4-channel digitizer card (1GSPS/channel).
Spectrometer 7-crystal XES spectrometer (http://dx.doi.org/10.1063/1.4803669)
40-crystal XRS (http://dx.doi.org/10.1063/1.4704458)
8-crystal von-hamos XES spectrometer (https://doi.org/10.1063/1.4737630)

Technical Specifications

Energy —

Energy Range Resolution ΔE/E Spot Size Flux Angular Acceptance
Focused 4800-18200 1.0-15 10-5 5x35um2 (or 100x700um2) ~3x1013 ph/s (Si111)
~ 4x1012 ph/s (Si311)		 N/A
Unfocused 18000-24000 10-4 500x2000um2 ~ 4x1011 ph/s (Si311) N/A

Optics —

M1 KB mirrors: Bent single crystal KB mirrors for a vertical and horizontal beam focusing. Rh and Si stripes provide selectable cutoffs at 11keV and 18.2 keV, respectively.
Monochromator: LN2 cooled, Si(111), ϕ = 0o , Si(311), ϕ = 0o. double-crystal.

Absorption —

127um Be