Photon Systems Breakout Lehman Review July 11, 2007 XTOD Diagnostics Photon Systems Breakout Lehman Review July 11, 2007

FEE (Front-End-Enclosure) LCLS Layout FEE (Front-End-Enclosure) Diagnostics SOMS HOMS Linac Undulator Hall X-Ray Tunnel FEH (Far Experimental Hall) NEH (Near Experimental Hall)

XTOD Commissioning Diagnostics and Offset Mirrors in the Front End Enclosure (FEE) Wall penetration K Spectrometer Indirect Imager Slit Solid Attenuators Collimators Wall penetration Thermal Sensor Fixed Mask Gas Attenuator Gas Detector Beam Direction Gas Detector Direct Imager (Scintillator) FEL Offset Mirror Systems

XTOD Optics and Diagnostics in FEE 5 mm diameter collimators Gas Detector Soft X-Ray Offset mirror system Hard x-ray Monochrometer (K Spectrometer) Direct Imager Solid Attenuator NFOV Slit e- Indirect Imager Total Energy Thermal Detector Hard X-Ray Offset mirror system Gas Attenuator WFOV Gas Detector Start of Experimental Hutches Muon Shield

Attenuator on order N2 boil-off (surface) Flow restrictor Gas detector Flow restrictor 4.5 meter long, high pressure N2 section Differential pumping sections separated by 3 mm apertures 3 mm diameter holes in B4C disks allow 880 mm (FWHM), 827 eV FEL to pass unobstructed Solid attenuators N2 Gas inlet Green line carries exhaust to surface Gas detector

Gas detectors share differential pumping with the Gas Attenuator PMT Electronics Photo Multiplier Tube Bandpass Filter Al liner 3 mm apertures along beam path Differential Pumping Section Magnet Coils Cylindrical Vessel Beam / Gas Interaction Region (~0.1 – 2 Torr N2) Magnet Power Supply and Controller APD Gas Feed And Pressure Control LCLS X rays cause N2 molecules to fluoresce in the near UV

Gas detector SSRL prototype Port for pumping Photo Multiplier Tube Magnet Coils Be window Gas Feed And Pressure Control Avalanche Photodiode Port for LED illuminator and florescence samples

Prototype Gas Detector insert for measuring x ray induced photoemission of candidate wall materials

Gas Detector signal vs. magnetic field at various pressures Simulated Measured

Results of SSRL Gas Experiments: Comparison Model and Experiments (2X correction of calculated signal) We suspect that discrepancy at lower pressures is due to photo electrons (and secondaries?) hitting the chamber ends

Measured luminescence of solids at 8 keV Al UV signal closely represented by 9:00, B on (red): Al is the best

Time dependence of gas detector signal from the 8keV fundamental UV signal within X rays scattered into walls ~ 1 ns X rays scattered into detector window ? Photoelectrons hitting walls 0 – 18 ns Photoelectrons hitting end caps 0 – 15 ns Secondaries hitting walls and end caps 0 – 200 ns (?) Energy of photoelectrons deposited into N2 0 – 45 ns

Indirect imager finds spontaneous core Raw soft spontaneous After reflection Princeton Instruments back illuminated CCD camera 25 x 25 mm chip, 20 um pixel size ML mirror 0.1% reflectivity, 1% bandwidth Status Indirect Imager: PRD in progress Vacuum chamber

Detector monochrometer measures intensity at a single point Channel-cut Si Monochrometer will be used to measure relative K of two undulator segments Monochrometer Two undulator spontaneous spectrum. Falloff of high energy tail is independent of aperture Detector Detector monochrometer measures intensity at a single point Linac E variation and measurement Use linac E variation and measurement to obtain other points along curve Two undulator spontaneous high energy falloff has highest slope when DK/K=0. Status K Spectrometer: PRD in progress

Total Energy (Thermal) Sensor provides calibrated measurement of FEL pulse energy Measures FEL energy deposition through temperature rise Cu heat sink Thermistors Nd0.66Sr0.33MnO3 (On back of substrate) Sensor Temperature Rise 1 2 3 4 5 0.05 0.1 0.15 0.2 0.25 0.3 Time [ms] Tc200 Tc150 Tc100 FEL pulse [K] 0.5 mm Si substrate t = 0 t = 0.1 ms t = 0.25 ms Thermal diffusion of FEL energy Status Thermal Sensor: PRD done SCR done PDR done Prototype done FDR in progress

Thermal sensor prototype Pulse tube cooler Optics for measuring, focusing, and steering laser beam 532 nm laser Sensor cryostat

Thermal sensor signal at 1mJ 2 volt bias 0 volt bias V1 V1 Vbias Rsensor R1 V1 V2 R3 R4 V2 V2

Channel 1 pulse at 400 uJ with 2V bias Subtract value at -100us Sample voltages at particular times, convert to DRcmr then to DT

Total energy prototype measured and predicted signal Finite difference prediction DT, °K DT, °K Measured data Absorbed Laser Energy, mJ Absorbed Laser Energy, mJ At 100 msec At 3 msec

Thermal sensor, preliminary design Thermal Detector Calibration Laser Laser Energy Meter

Scintillators on movable shaft Photodiode for K measurement Direct Imager 30 fps CCD Camera Scintillators on movable shaft ND filter wheel High resolution lens 4 Scintillators: Thin, stops 8 keV FEL find soft x-ray FEL Very thin, stops 826 eV FEL Thick, stops spontaneous spontaneous studies + one other for tests diamond Stops FEL Transmits spontaneous Photodiode for K measurement 30 fps CCD Camera Low resolution lens

Direct Imager, preliminary design Single shot measurement of f(x,y), x, y ,u Camera Status Direct Imager: PRD done SCR done Prototype done PDR done in Final Design Scintillators

Scintillator emission spectrum Camera QE Scintillator emission spectrum

Soft X-Ray Spontaneous signal in WFOV Direct Imager Absorbed in 5 um YAG, Maximum ~ 20,000 photoelectrons/pixel Camera: Photometrics 512B Objective: Navitar Platinum 50 Power: 0.1365 NA: 0.060

Scintillator signals in FEL equivalents Needed x-ray attenuation Needed x-ray attenuation YAG Range Needed visible attenuation CCD Range Need x-ray attenuation of > 100 and visible attenuation of > 10

Prototype Direct Imager testing Flat field testing of camera only Enclosure CCD Integrating Sphere Camera Pulsed UV laser testing with YAG WFOV Optic UV beam splitter N2 Laser YAG Insertable photodiode Lens ND filter Photodiode

Photon Transfer Curve Our fit: Manufacturer:

Cascade 512B on-chip gain measurements On-Chip: 0 to 4000, Exposure Time: 5 to 190 Lamps: 1, 2 Measured Gain = Slope g(j)/Slope g(0) On-Chip Gain Measured Gain Slope 45.09 500 62.44 1000 77.59 1500 106.06 2000 168.20 2500 307.83 3000 848.24 3500 2723.20 1.00 1.38 1.72 2.35 3.73 6.83 18.81 60.39 February 12, 2007 Run 12

Direct Imager image of N2 laser excited YAG scintillator at 20 Hz YAG excited by N2 laser Boundary of 10 mm dia. YAG disk

FEL Offset Mirror Systems have “Pop-in” imagers for alignment

Bidirectional Popup Viewer allows viewing of the x-ray beam and the collimator

We are studying expected signal levels in the Pop-in cameras Low Energy, All undulator modules 100% Spontaneous Propagated through fixed mask, pipes 12 Boron Carbide windows are open Slit is open No attenuation, no gas detector Photons absorbed in 1 mm YAG, Full Well: 200,000 # photoelectrons ~ 5660 per pixel Misses Mirror 1 Reflected off Mirror 1 SOMS Run005

Progress continues on XTOD diagnostics: Summary Progress continues on XTOD diagnostics: Procurement - Slit, Fixed Mask, Attenuator PDR – Direct Imager, SOMS, Thermal Detector SCR – K-Spectrometer PRD – HOMS, Indirect Imager