R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop Use of FEL Off-Axis Zone Plate Spectrometer to measure relative K by the Pinhole/Centroid method LCLS Beam-Based Undulator K Measurements Workshop November 14, 2005

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop Baseline Diagnostics Solid Attenuator Gas Attenuator High-Energy Slit Start of Experimental Hutches 5 mm diameter collimators Muon Shield FEL Offset mirror system Total Energy Calorimeter WFOV Direct Imager Scanning Spectrometer / Indirect Imager mirrors Windowless Ion Chamber e-e- Diagnostic Package NFOV Direct Imager FEL Spectrometer and Direct Imager in 2 nd Hutch of NEH

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop 8.26 keV Transmission Grating P = 200 nm N = 500 D = 100  m Sputter-sliced SiC / B 4 C multilayer 33  m thick Beam 100  m Interference Function Single Slit Diffraction Pattern Observed Intensity angle

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop Sputter-Sliced SiC/B 4 C Grating SiC B4CB4C

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop Sputtered-sliced multilayer gratings as high bw spectrometers 5-  m-thick Mo/Si multilayer (d=200 Å) on Si wafer substrate. Thinned and polished to a 10-  m-thick slice SEM image of Mo/Si multilayer

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop Parabolic wave calculation shows > 10 nm thick gratings with 2 nm periods do not work diffraction peaks in far-field no diffraction peaks in far-field 2 nm period 10 nm 2 nm period 50 nm

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop Long grating acts like a coupled waveguide 10 nm long grating shows some cross coupling in near-field 50 nm (or longer) shows complete cross coupling in near-field Parabolic wave calculations by Jeffrey S. Kallman

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop 200 nm period x 33 microns works diffraction peaks in far-field 200 nm period 33  m Waveguide coupling limits us to periods > 200 nm

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop Spectrometer location in FEE to measure Spontaneous Radiation Thick Slit Be mirrors 1 & 2 Attenuators SiC Mirror 1 Put camera here SiC Mirror 2 5 mm dia. Collimator m Diagnostics Package Contains Grating and Variable Slit

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop Position of Spontaneous Spectrometer OpticCamera 5 m

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop FEE Schematic with Transmission Grating Spectrometer Solid Attenuator Gas Attenuator Thick Slit Start of Experimental Hutches 5 mm diameter collimators Muon Shield FEL Offset mirrors Grating WFOV Direct Imager Spectrometer Imager Windowless gas detectors Variable Slit e-e- Diagnostic Package

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop 1st Order Diffraction Peaks 4 mm FEL Transmission Grating Spectrometer Thick Slit 5 cm Ta capped with 1 cm B 4 C YAG Scintillator 50 microns thick Thin Adjustable Slit 1 mm Ta Very high energy photons go through everything micron 1 mm 6 m Transmission Grating 200 nm Period 100 micron Aperture 5 m

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop Monte Carlo Generation of Photons from Near-Field Calculations Photons are aimed at Sven’s near field distributions… … but allowed to reflect off of the vacuum pipe or get absorbed in the breaks Slits, gratings and scintillator placed in beam

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop Grating P = 200 nm Number of P = 500 Distance = 5 m 8.26 keV FEL Only photons FEL ~ 160  m FWHM

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop Simulated Scattering angle for photons through grating   Rad

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop 5 m downstream of grating

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop Shadow of optic defines center

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop First order peaks are 100 microns across for FEL Distance  E/E /P*f3750  m 1 Pixel Size 10  m 2.7x /N 7.5  m 2x10 -3 Aperture 100  m 2.7x10 -2

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop Off-Axis Zone Plate Spectrometer Zone plate axis Beam Axis l > l 0 l < l 0 l = l 0

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop Off-Axis Zone plate Focal Length m Offset 3750 microns 50 and 100  m aperture Distance = 5 m Starting Zone 20204, 185 nm Ending Zone 21296, 181 nm 8.26 keV FEL Only photons FEL ~ 160  m FWHM

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop Scintillator Image Positive Negative

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop Scintillator Image around 5% Bw Resolution is 2.36*4.8 microns/4092 microns = 3 x = 23 eV

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop 50 micron aperture diffraction Resolution is 2.36*7.9 microns/4092 microns = 5 x = 38 eV

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop Wavelength calibration = nm  =  m = nm  =  m

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop First Undulator Segment 1st undulator segment emits Thick slit 1 mm wide 1 x 1 mm single undulator distribution simulated from 7.5 to 8.5 keV Thin slits forming crossed 100  m apertures in x and y

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop Initial photon position and energy First Segment

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop Zero order peak, First Segment

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop Area near first order First Segment

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop First Segment Normalization Sven’s near-field calculation –2 x 2 mm –8.0 to 8.5 keV –79 nC –0.034  J –2.553 x 10 7 Photons Simulation –10 7 Photons simulated –31 nC Scale Monte Carlo by x for full pulse

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop Spectra of nominal First Segment 1403 photons in simulation => 3600 ± 100 in a 79 nC pulse Fitted centroid:  = ± 0.07  m Need at least x 200 more photons!

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop Spectra of First Segment Detuned by photons in simulation => 3600 ± 100 in a 79 nC pulse Fitted centroid:  = ± 0.07  m

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop Spectra of First Segment Detuned by photons in simulation => 3700 ± 100 in a 79 nC pulse Fitted centroid:  = ± 0.07  m

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop Last Undulator Segment Last undulator segment emits Thick slit 1 mm wide Thin slits forming crossed 42  m apertures in x and y 1 x 1 mm single undulator distribution simulated from 7.5 to 8.5 keV

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop Initial photon position and energy Last Segment

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop Zero order peak, Last Segment

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop Area near first order Last Segment

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop Spectra of nominal Last Segment 303 photons in simulation => 3300 ± 200 in a 79 nC pulse Fitted centroid:  = ± 0.3  m

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop Last Segment Normalization Sven’s near-field calculation –2 x 2 mm –8.0 to 8.5 keV –79 nC –  J –1.090 x 10 8 Photons Simulation –10 7 Photons simulated –7.2 nC Scale Monte Carlo by x 10.9 for full pulse

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop Spectral Measurements Summary Fit Centroid  m Spectral Shift,  E/E From Last Nominal x From First Nominal x Last Nominal ± ± ± 0.8 First Nominal ± ± ± 0.2 First detuned ± ± ± 0.2 First detuned ± ± ± 0.2

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop Expected variations in 1 On axis: Effect of changing K But

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop Simulation of Last segment full spectra, full angular distribution

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop Last Segment Full Field Normalization Sven’s near-field calculation –120 x 40 mm –0.0 to keV –79 nC –  J –5.274 x Photons Simulation –10 7 Photons simulated –0.015 nC Scale Monte Carlo by x 5274 for full pulse

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop Observed in scintillator, Last segment, full field One simulated photon = 5274 real photons We expect a signal of 3300 real photons here

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop Thin scintillator reduces background by x 7 ± 3 All photons 7 photons in simulation ± in a 79 nC pulse Photons stopping in scintillator 1 photons in simulation 5300 ± 5300 in a 79 nC pulse Conclude backgrounds of 5300 ± 5300 in a 79 nC pulse

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop Summary Investigated 100 micron aperture FEL Transmission Grating for use in measuring K Sensitivities are roughly at the limit of what is needed Signal level is too low by at least a factor of 200. More aperture, say 1.4 x 1.4 mm would help. Larger focal distance would allow larger periods Signal:Backgrounds with thin scintillator are at least 1:1 Beam stability and pointing (relative to the 100 micron aperture) will be an issue that is not investigated here

R. M. Bionta SLAC November 14, 2005 UCRL-PRES-XXXXXX LCLS Beam-Based Undulator K Measurements Workshop Monte Carlo used for design of Single Shot keV Spectrometer Sm K  40.1 keV Sm K  45.4 keV   E1E1 E2E2 No filter 25  m Sm filter Straight-thru bkg W/SiC bilayers d = 2 nm  B =0.45 deg keV > 90% LCLS Monte- Carlo Simulation