ESRF. Tests of a diamond quadrant detector at Hasylab (DESY) using the Libera Brilliance. European Synchrotron Radiation Facility, France

Transcription

1 Tests of a diamond quadrant detector at Hasylab (DESY) using the Libera Brilliance J Morse European Synchrotron Radiation Facility, France H Graafsma Hasylab, DESY, Germany ESRF B Solar Instrumentation Hasylab, DESY, Technologies, Germany Slovenia 1

2 Acknowledgements Eleni Berdermann Michal Pomorski Harris Kagan GSI Darmstadt CEA-Saclay Ohio State Unversity Muriel Salomé Liam Gannon ESRF Grenoble University of Bath 2

3 Talk Outline Objectives: - evaluate the feasibility of using RF readout with diamond beam position monitors; - compare performance, practical issues with the (usual) electrometer read-out approach. 1. X-ray Synchrotron beam monitoring requirement why diamond? 2. some background: tests at ESRF 3. the Libera Brilliance system 4. DESY F4 beamline measurements/results 3

4 global application scale 2009: about 50 synchrotrons in the world infra-red to MeV photon beams, but main interest 5 ~ 50keV ESRF-Grenoble 4 4

5 local application : ESRF European Synchrotron Radiation Facility ESRF ~5000 external user experiments / year with high intensity, coherent X-ray beam probes 0.5 ~ 500keV basic and applied research in biology (protein structures ) materials science chemistry, catalyisis (coherent) imaging -- at micro, nano, molecular & atomic scales 5

6 3 rd generation synchrotrons ~ 50 beamlines ESRF Ø300m undulator source 50 ~100m source to end station monochromatic beam ~mw white/pink beam 0.2~2kW Beam position - intensity monitors 6

7 3 rd generation synchrotrons ~ 50 beamlines ESRF Ø300m undulator source 50 ~100m source to end station monochromatic beam ~mw white/pink beam 0.2~2kW Beam position - intensity monitors 7

8 X-ray beamline monitoring requirements Position Intensity: required beam stability ~10% of beam size 0.1 ~ 50µm, nanofocusing goals 10nm measurement rates required dc ~ 1kHz (acoustic vibrations!) accuracy & linearity requirement 0.1% Timing: device synchronization with optical lasers in ~psec pump probe experiments (X-ray photon bunches ~50psec at 10 5 ~10 8 pulses/sec minimal beam interference: absorption, scattering, coherence loss beamline compatibility: package size, operation in air, dirty-vacuum, clean-uhv ionizing radiation load >10 4 Gray/sec max. absorbed X-ray power: few mw monochromatic beams but 100W in ~mm 2 white beam applications: ONLY possible with diamond 8

9 why diamond? Z = 6 low specific X-ray absorption / beam scattering and short range of photoelectric- or Compton electron Thickness for 5% absorption (microns) ~practical limits single crystal CVD Diamond (Z= 6) Silicon (Z= 14) X-ray energy (kev) - zero leakage current can use high E-field nsec response - simple devices can be radiation hard - outstanding thermal conductivity diamond 2000, cf. Si 150 (Wm -1 ºK -1 ) 9

10 XBIC, Poly- and single crystal response XBIC: signal current maps made from x, y raster scan of micron X-ray beam Polycrystalline: grain-boundaries trapping and local field distortions, signal response lag X-ray scattering Single Crystal: excellent spatial uniformity unity gain charge collection with blocking contacts 1σ signal variation 0.103% over 100 point row 10

11 signal lag with fine-grain polycrystalline 10 sec Charge collection increases (prompt + detrapped) with E field 1 5v/µm beam 15 x 100µm 2, 1.3 x ph/sec at 12keV Ralf Menk, 2006 SLS data on polycrystalline ~10µm thick (sourced by Diamond Materials??) 11

12 operation of diamond XBPM devices diamond plate, thin (30 100µm) diamond with X-ray transparent <100nm surface contacts Cr, Ti, Ni, Al (Au, Pt, W)) in beam, diamond bulk acts as solid state ionization chamber electron thermalization range ~few microns current signal readout DC up to synchrotron RF clock frequencies possible position (and intensity) found with multiple electrodes: exploits diffusion splitting (~10µm) of charge e.g. simple quadrant motif difference/sum of electrode currents A, B, C, D givesbeam 'centre of gravity sum of currents gives beam intensity X = Y = Y X A B C D ( A + C) ( B + D) A + B + C + D ( A + B) ( C + D) A + B + C + D 12

13 operation of diamond XBPM devices diamond plate, thin (30 100µm) diamond with X-ray transparent <100nm surface contacts Cr, Ti, Ni, Al (Au, Pt, W)) in beam, diamond bulk acts as solid state ionization chamber electron thermalization range ~few microns current signal readout DC up to synchrotron RF clock frequencies possible position (and intensity) found with multiple electrodes: exploits diffusion splitting (~10µm) of charge e.g. simple quadrant motif difference/sum of electrode currents A, B, C, D givesbeam 'centre of gravity sum of currents gives beam intensity X Y = = Y X A B C D ( A + C) ( B + D) A + B + C + D ( A + B) ( C + D) A + B + C + D Packaged device, ID09B, ID11, Desy F4 tests 13

14 operation of diamond XBPM devices diamond plate, thin (30 100µm) diamond with X-ray transparent <100nm surface contacts Cr, Ti, Ni, Al (Au, Pt, W)) in beam, diamond bulk acts as solid state ionization chamber electron thermalization range ~few microns current signal readout DC up to synchrotron RF clock frequencies possible position (and intensity) found with duo- multiple and electrodes: tetra-lateral devices exploits linear diffusion position response splitting (~10µm) of charge e.g. over simple several quadrant mm motif difference/sum of electrode currents A, B, C, D (but less precise) givesbeam 'centre of gravity sum of currents gives beam intensity X Y = = Y X A B C D ( A + C) ( B + D) A + B + C + D ( A + B) ( C + D) A + B + C + D Packaged device, ID09B, ID11, Desy F4 tests 14

15 operation of diamond XBPM devices diamond plate, thin (30 100µm) diamond with X-ray transparent <100nm surface contacts Cr, Ti, Ni, Al (Au, Pt, W)) in beam, diamond bulk acts as solid state ionization chamber electron thermalization range ~few microns current signal readout DC up to synchrotron RF clock frequencies possible position (and intensity) found with duo- multiple and electrodes: tetra-lateral devices exploits linear diffusion position response splitting (~10µm) of charge e.g. over simple several quadrant mm motif difference/sum of electrode currents A, B, C, D (but less precise) givesbeam 'centre of gravity sum of currents gives beam intensity X Y = = Y X A B C D ( A + C) ( B + D) A + B + C + D ( A + B) ( C + D) A + B + C + D Packaged device, ID09B, ID11, Desy F4 tests ID06 tests see Pomorski talk! 15

16 metal contacted devices, X-ray response I-V curves under steady-state X-ray beam illumination (7.2 and 6.0 kev) bias Lift-off litho evaporated contacts (Glasgow University) 333µm C* 0.5V/µm 130nm Au 30nm Pd 10nm Ni 10nm Ti (annealed) 30nm Pd 130nm Au current (na) current gain Blocking contact(s) give saturated current response for >0.3Vµm -1 applied E field: bias (V) overbias excellent area response uniformity Shadow mask, sputtered contacts (GSI Darmstadt) current (na) V/µm bias 96µm C* bias (V) ~100nm Al ~100nm Al Si beam flux calibration ε Diamond = /-0.2 ev/e-h pair (ESRF, MI-885) 16

17 quadrant devices: position response ID21 data, beam collimated 200µm For large beamsize (> 50µm), device crossover response is simply the line integral across the beam intensity profile 1 2 diamond signal (na) isolation gap betweeen 1 quadrants ~120µm 2 Line 7.2keV 50% parallel X-beam through 0.2mm pinhole upper left quadrant lower left quadrant!! This data from 0-10Hz bandwidth electrometer measurements, i.e. charge integral measurements what about the time domain?? For a small beam (< 10µm), crossover response is convolution of photoelectron thermalization range and lateral charge diffusion ocurring during drift signal (na) position (mm) signal slope ~0.5% /micron isolation gap Isolation between gap quadrants ~120µm~120um focussed X-beam 0.4 x 1.2 µm 2 FWHM 50% beam focused <1um bias -40V position (mm) signal slope ~5% /micron 17

18 Vertical & horizontal position time scans ESRFMI-885, ID21 microfocus beamline 1sec/point: beam shifts position* (µm ) vertical horizontal *scaling 'calibration' error possibly ~10% X-ray flux ~10 8 s -1 at 7keV ~ 20fC in diamond per X ray bunch ~ 10nA dc equivalent signal current) time (sec) 18

19 Vertical & horizontal position time scans position* (µm m) ) ESRFMI-885, ID21 microfocus beamline 1sec/point: beam shifts x time zoom vertical vertical horizontal horizontal refill position (µm) x time zoom horiz position residuals sd µm over 145 points/240secs σ =13.3nm rms *scaling 'calibration' error possibly ~10% time (sec) position (µm) x time zoom residuals sd µm over 100 points/166secs (section A->B) vert position B *scaling *scaling 'calibration' 'calibration' error error possibly possibly ~10% ~10% X-ray flux ~10 8 s -1 at 7keV ~ 20fC in diamond per X ray bunch ~ 10nA dc equivalent signal current) time (sec) A σ = 20.4nm rms time (sec) *scaling 'calibration' error possibly ~10% 19

20 position timescan and vibrations, ID09B: ID09B 23 June currents measured with Keithley 485 electrometers, (10Hz BW, mean current/electrode ~10µA Æ charge generated in diamond ~ 100 fc /pulse 4.4 hours seconds ID09B 23 June µm 47 1µm sum of 4 qaudrant signals (µa) 0 1 = 20um (vertical) beam position 1 = 60um (horiz) ~ 14 kev beam Amplitude sum of 4 qaudrant signals (µa) 1 = 20um (vertical) 1 = 60um (horiz) 0.3 beam position Vertical noise amplitude Average of 10 FFT of 1000 samples Frequency (Hz) FFTs using Femto DLPCA-200 current preamps (simultaneous sampling ADCs at 1ksample/sec) seconds Machine artifacts or something upstream on beamline 20

21 diamond temporal response ESRF 4 bunch mode, ID21 beam ~10 8 ph/sec mean flux (very weak beam intensity ) 700ns Vb=-50V 0.5m 5m DBA-3 LeCroy scope LC584A, ~1GHz BW <100pS FWHM X pulse duration 2.3GHz, 38dB 21

22 diamond temporal response ESRF 4 bunch mode, ID21 beam ~10 8 ph/sec mean flux (very weak beam intensity ) 700ns Vb=-50V 0.5m 5m DBA-3 LeCroy scope LC584A, ~1GHz BW <100pS FWHM X pulse duration 2.3GHz, 38dB Signal response to crossing of one X-ray bunch absorption of ~160 photons at 7.2keV (total ~1MeV = 12fC /pulse ) Linear fit to slope gives signal full base width ~2.5ns, e- drift velocity ~40 µm ns -1 at ~1.1 V µm -1 22

23 wideband position measurements, ID09B S361-1, sample TiW contacts processed by Kagan-OSU. X-ray beam boxcar signal integration 200mV/20ns division (after 10dB attenuator) signal direct to DSO: poor decoupling and 50Ω matching signal bounce 20keV beam, incident flux ~1 x 10 7 ph per pulse (1kHz mechanically chopped white beam) ~ 5% X-ray absorption in diamond 385µm thick, ~50% photoelectric/50% Compton ~50pC/pulse in diamond (diamond electrode capacity ~ 0.5pF, bias at 500V CV charge limit ~200pC) electrode signal ~60ns integrals Vertical beam scan 1 4 2mm Quadrant signal 1 50µm 4 crossover response of electrodes, beam size fwhm 40µm (V), 90µm (H) Spatial position (motor scan of diamond) 23

24 i-tech Libera Brilliance system Signals in !! developed for stabilization of electron beams X, Y, Σ out over network High performance if adequate tuned RF signal power but can it work with diamond signals? 25 ppm ~10kHz 24

25 what s inside? performance? analog stage: tuned filter (352 or 500MHz) 25

26 what s inside? performance? analog stage: tuned filter (352 or 500MHz) 3000 data with attens set auto?? ADC value isg/d-bpmlibera/1/adcchannela ADC sample # 26

27 what s inside? performance? analog stage: tuned filter (352 or 500MHz) ADC value data with Libera attens set auto?? and ~40mV data signal with pulse attens amplitude set auto in)?? ADC value isg/d-bpmlibera/1/adcchannela ADC sample # ADC sample # 27

28 what s inside? performance? analog stage: tuned filter (352 or 500MHz) ADC value data with Libera attens set auto?? and ~40mV data signal with pulse attens amplitude set auto in)?? ADC value isg/d-bpmlibera/1/adcchannela ADC sample # ADC sample # FPGA and µp processing buffering, fast I/O 28

29 what s inside? performance? analog stage: tuned filter (352 or 500MHz) ADC value data with Libera attens set auto?? and ~40mV data signal with pulse attens amplitude set auto in)?? ADC value Rok Uršič, I-Tech Dec 2004 for Libera Electron isg/d-bpmlibera/1/adcchannela ADC sample # ADC sample # FPGA and µp processing buffering, fast I/O 29

30 what s inside? performance? analog stage: tuned filter (352 or 500MHz) ADC value data with Libera attens set auto?? and ~40mV data signal with pulse attens amplitude set auto in)?? ADC value Rok Uršič, I-Tech Dec 2004 for Libera Electron Guenther Rehm Diamond Light Source, isg/d-bpmlibera/1/adcchannela ADC sample # ADC sample # synchrotron circulating e- beam position noise for Libera input signal attenuators 0-28dB FPGA and µp processing buffering, fast I/O 30

31 RF readout: Doris F4 tests May 2009 ESRF-Desy DIMOX collaboration (readout of diamond BPMs using Libera electronics) DORIS F4 BM white beam exit slits Si diode diamond BPM 20 x 20µm 2 0.5mm on motorized x-y stage Bias (NIM unit) Al beam absorber plate(s) mm preamps Libera Brilliance 8mm E6 SC diamond in ceramic mount before PCB assembly. 389µm thick, 50µm isolation cross, 3mm hole under the diamond for beam passage. ~100nm TiW contact processing: Harris Kagan, OSU 31

32 diamond mounting and RF signal cabling Bias Sample X-ray Beam Control System Four quadrant Single Crystal Diamond Sensor RF Signal Libera Impendence Matching Circuit BPM Electronics Modified Brilliance: new +12dB input preamps after crossbar switch 32

33 Doris F4 bending magnet X-ray beam 6.0x10 7 DesyEnergyProfile.opj Flux (photons/s/mm 2 /0.1%bw) 4.0x x10 7 Initial bending magnet flux after 0.5mm Al and 0.5mm Si after2.0mm Al and 0.5mm Si after 3.5mm Al and 0.5mm Si Flux incident on diamond after 0.5mm Al absorber ~1.1 x ph/sec 2.9% of incident beam absorbed (photoelectric and Compton) dc equivalent current generated in diamond ~15µA (3pC/ pulse at 5Mpps) x x x x x10 5 Energy (ev) effect of full white beam on PCB and diamond Following measurements shown were made after these accidents 33

34 Three slides of results removed from this presentation (these show data that will be included in a publication in preparation) Please contact speaker directly for these missing slides (morse@esrf.fr) 34

35 dynamic position response: jump test Libera ADC buffer data at 130KHz sampling-average µm µm rms position noise* vs. bandwidth nb. noise includes real beam-sensor movements etc. 35

36 device modeling with TCAD Sentaurus High level modeling software for semiconductor devices: 2 & 3D graphics and script input to describe simple to complex devices. Program solves Poisson and charge continuity (finite element methods) equations. Simulates drift, diffusion, recombination etc. of charge carriers, and signals induced on electrodes for various external load models Accurate/well tested for silicon devices: input parameter and model files can easily be configured for other semiconductor materials. Following slides show FIRST ATTEMPTS at 2D simulations for diamond using permittivity = 5.7 band gap = 5.47 ev electron/hole mobility = 2300/1800 (cm 2 / Vs) carrier velocity saturation model?? 36

37 boundary conditions, field map and meshing anode 1 anode 2 200µm cathode L Gannon, Sentaurus Device Editor 37

38 Signal development during charge transit 0V µm 0V 20µm 400µm ball of charge bias -550V Sentaurus Device Simulator 1. charge created near the cathode 2. holes reach the cathode and are collected, so signal current is ~halved 3. electrons drift and diffuse across a region of homogenous electric field. 4. as electrons approach anode 1, electric field gradient increases so a rise in current is observed on this anode. 5. As electrons are collected at anode 1 the current decreases to zero (tailing caused by transit diffusion) Current (A) 2.4x x x x x x x x x x x x x x x x x x10-9 Time (s) Current (A) 2.4x x x x x x x x x x x x x x x x x x10-9 Time (s) 38

39 Signal variation with position of incident beam 200µm 0V 1 2 0V 400µm column of charge bias=-550v Sentaurus Device Simulator Current (A) 4.0x x x x x x x10-6 anode 1 anode 2 3.5x x x x x x x x x x x x x10-9 4x10-9 6x10-9 8x x x10-9 4x10-9 6x10-9 8x10-9 Time (s) Time (s) Current (A) 39

40 Conclusions: Proof of principle established for position readout using Libera Brilliance system resolution < 0.1µm demonstrated, but initial DESY tests limited by (white) beam size and beam position noise Further quantitative tests needed to directly compare narrowband RF vs. electrometer readout, especially signal/noise performance vs. absorbed beam energy (new test in planning, will use ~10keV monochromatic X-ray beam at ESRF) Better understanding needed of signal development in multi-electrode device coupled with response of signal processor, e.g. Libera: system ~2MHz passband at 352MHz (modelling just started with TCAD-Sentaurus) 40