Kaori Hattori 1,2 Chihiro Ida 1,2 , Kazuki Ito 2 , Kotaro Fujii 3 , Hidetoshi Kubo 1,2 , Kentaro Miuchi 1,2 , Masaki Takata 2,4,5 , Toru Tanimori 1,2 , Hidehiro Uekusa 3 1 Department of Physics, Kyoto University, Japan 2 Structural Materials Science Laboratory, RIKEN Harima Structural Materials Science Laboratory, RIKEN Harima Institute/SPring ‐ 8 Center, Japan 3 Department of Chemistry and Materials Sicence, Tokyo Institute of Technology, Japan 4 SP i 4 SPring ‐ 8/JASRI, Japan 8/JASRI J 5 Department of Advanced Materials Sciences, Graduate School of Frontier Sciences, The University of Tokyo 2008/8/30 1
OUTLINE OUTLINE • Development of detectors for structural • Development of detectors for structural determination • Requirements for photon counting detectors • Novel photon counting detector Novel photon counting detector, mico ‐ pixel chamber ( μ ‐ PIC) • Time resolved experiments • Small angle X ‐ ray scattering (SAXS) experiments • Small angle X ‐ ray scattering (SAXS) experiments • Summary 2008/8/30 IUCr 2008 Osaka, Japan 2
To provide powerful methods To provide powerful methods for structural determination • High speed Structural analysis of biological macromolecules (protein ） materials materials � radiation within a couple of minutes • High precision � wide dynamic range of >10 7 y g � realize high precision measurements � Structural determination of materials with light elements • Time resolved active dynamics active dynamics photon ‐ induced phase transition record continuum transition with a time resolution of sec to sub ‐ msec repeated measurements will provide better time resolution p p To satisfy these conditions Photon counting detectors with good position resolutions are suitable 2008/8/30 IUCr 2008 Osaka, Japan 3
1. Position resolution better than 100 μ m 2 Counting rates > 10 7 mm ‐ 2 >1000 × MWPC (irradiated locally) 2. Counting rates > 10 7 mm 2 , >1000 × MWPC (irradiated locally) 3. Large active area of > 150 × 150 mm 2 4. No dead region (ex. junctions) 5. Efficiency difference < 1 % 6. Image distortion < 1 % Readouts without intervals 7. Operation at room temperature, low power consumption 7. Operation at room temperature, low power consumption → CRP (continuous rotation photograph) method → CRP (continuous rotation photograph) method High gain 8. Easy maintenance → sensitivity to low energy X-rays of about 1 keV 9. Low costs Anomalous X A A Anomalous X-ray scattering of sulfur l l X X ray scattering of sulfur (2.3keV tt tt i i f f lf lf (2.3keV ） (2 3k V ） (2 3k V A photon counting area detector based on a Micro Pixel Chamber ( μ ‐ PIC) has realized 4, 6, 7, 8, and 9. 1, 2, and 5 are in progress. 3. A n active area of a μ ‐ PIC currently in use is 100 × 100 mm 2 A μ PIC with an active area of 300 × 300 mm 2 has proved stable runs A μ ‐ PIC with an active area of 300 × 300 mm 2 has proved stable runs. � Verification experiments at a synchrotron radiation facility are being planned. 2008/8/30 IUCr 2008 Osaka, Japan 4
Mechanism for photon detection � Photoelectric effect in a gas GEM GEM � Emitted electron runs until it loses a kinetic energy � Emitted electron runs until it loses a kinetic energy （ gas electron multiplier) � Ionizes atoms � Electron clouds are amplified by a GEM(gas electron multiplier F Sauli 1997) GEM(gas electron multiplier, F. Sauli, 1997) , and μ -PIC and μ -PIC 70um 140um 4 4mm 0.4kV/cm 100 100 mm 4mm 1.9kV/cm Pixel pitch 400 400 μ m μ m 400 μ m Gas gain IUCr 2008 Osaka, Japan 5 μ -PIC : 3 × 10 4 GEM: 3
μ ‐ PIC is kept in the sealed vessel � The μ -PIC is contained in a sealed vessel with a polyimide 100 mm entrance window of 0.1-mm thi k thickness. � The vessel is filled with Xe- C 2 H 6 (70:30) gas. � Stable operation without fresh � St bl ti ith t f h gas supply for > 1 month A Anode 256ch + cathode 256ch d 256 h + th d 256 h Signals from the μ -PIC are sent via the printed circuit boards Sealed vessel S l d l from μ -PIC Printed circuit Outside μ PIC μ -PIC 256ch per board 256ch per board board pre -amplifier -amplifier to pre-amplifiers 2008/8/30 IUCr 2008 Osaka, Japan 6
Data acquisition (DAQ) q ( Q) ASD Position Encoding Detector Module ( μ -PIC) 100 MHz memory position, LVDS board clock out Cathode 256 ch ( X T ) ( X, T ) VME b VME bus 33 bit Amplifier ( Y, T ) Shaper PC Discriminator (ASD) Digital out 256 ch (LVDS) The output charges of the 256+256 channels are parallel pre-amplified, The output charges of the 256+256 channels are parallel pre-amplified shaped, and discriminated by the ASD chips completely digitized Digital signals are sent to the position encoding module with an internal clock of 100 MHz, allowing the recording of position ( X or Y ) and the timing T clock of 100 MHz, allowing the recording of position ( X or Y ) and the timing T in the memory module 2008/8/30 IUCr 2008 Osaka, Japan 7
• Simple S p e • Low cost • Easy adjustments for detectors with large active area • Fast readout • Characteristic less depends on counting rates Ch i i l d d i • Good counting rate capabilities g p • μ ‐ PIC > 1 MHz charge division < 1 MHz delay line 2008/8/30 IUCr 2008 Osaka, Japan 8
Irradiated scattering from Irradiated scattering from the best fit of exponential function the best fit of exponential function a piece of glassy carbon x 1.038 0.9 Å Error ： 0.7% good linear correlation from 20 cps to 5 Mcps from 20 cps to 5 Mcps Dynamic range of > 10 5 No saturation No saturation counting rates are li limited by a high voltage it d b hi h lt module 2008/8/30 IUCr 2008 Osaka, Japan 9
2-dimensional imaging gaseous detector 400 μ m pitch 400 μ m, pitch 400 μ m, size 100 mm × 100 mm, 300 mm × 300 mm position resolution Theoretical limit 10cm 10cm σ = d = μ ~ 120 μ m / 12 115 m Knife edge test Knife edge test Projected image of the test chart edge Projected image of the test chart edge and the best fit of the error function A. Takeda et al., IEEE Transactions on nuclear science, 2008/8/30 IUCr 2008 Osaka, Japan Vol. 51, No.5, (2004) 10 X-ray image of test chart and the projected image along 0.5 mm slits
CRP (continuous rotation photograph) method Movie of diffraction spots from rotating crystals a crystal rotated by a goniometer a crystal rotated by a goniometer timings of incident photons converted to rotation angles of diffraction spots Reducing the measurement time Strong background reduction using a new parameter, rotation angle � integrated diffraction spots 2008/8/30 IUCr 2008 Osaka, Japan 11
Crystal Ref. # R-factor time (I > 2 σ ) (sec.) C H NO C 4 H 9 NO 6 1 406 1,406 7 9% 7.9% 2 1 2.1 C 20 H 37 CoN 6 O 4 4,361 9.8% 300 MSGC( Micro Strip Gas Chamber ) ( p ) C 25 H 26 O 4 4,565 , 8.4% 80 25 26 4 Reciprocal lattice Time Time Movie varying 2 θ continuously Movie varying 2 continuously Time resolution of ~ 100 ns for each X Time resolution of ~ 100 ns for each X ray Time resolution of ~ 100 ns for each X Time resolution of ~ 100 ns for each X-ray ray ray Much Information Much Information - -> quick online analysis > quick online analysis 2008/8/30 IUCr 2008 Osaka, Japan 12
rotation speed : 4.89 sec/cycle mesurement time : 3716 sec mesurement time : 3716 sec counting rate : 1.05 × 10 4 cps Applying the noise reduction pp y g using 2θ information 3716s 2 θ <49 o Reflections 1556 (331 unique) Rint (internal agreement factor) 3 7% Rint (internal agreement factor) 3.7% Rint of 1% will achieve with ten times the length of accumulation time 2008/8/30 IUCr 2008 Osaka, Japan 13 Takeda et al. J. Synchrotron Rad. (2005) 12, 820-825
BL14A 17.5keV μ PIC μ crystal 2008/8/30 IUCr 2008 Osaka, Japan 14
KEK Photon Factory 0.7 Å Dehydration reaction of a pyromellitic acid hydrate occurs y py y while heat is applying (140 ℃ ) hydrate hydrate dehydrate 65 sec Change in a diffraction pattern in 7 sec 2008/8/30 IUCr 2008 Osaka, Japan 15
The intensity I ( 2 θ , t ) is expressed as I = xI d (2 θ )+ (1- x ) I h (2 θ ) , where I d (2 θ ), I h (2 θ ) is the intensity of the dehydrate, the hydrate, respectively, including a background 0 sec 1.95 sec 3.90 sec 6.50 sec 4.3 × 10 4 events / 0.65 sec 16 Time resolution will be expected to about 4 msec with a count rate of 10MHz
target Camera length 0.6 ～ 3.5m beam μ -PIC 2008/8/30 IUCr 2008 Osaka, Japan 17
0.9 Å , 1.2 × 10 5 cps 11 22 22 Diffraction patterns of collagen with a μ -PIC X-ray imaging system Diffraction patterns of collagen with a μ -PIC X-ray imaging system with an accumulation of 10 6 events, 10 5 events, and 10 4 events, respectively. Signal-to-noise ratio in the background of the diffraction pattern was improved 2008/8/30 18
100 mm � Th � The peaks observed at the holes on the mask moved k b d t th h l th k d < 10 μ m when the beam intensity was varied from 8 to 200 kcps Holes were perpendicularly arranged The deviation from the perpendicular was <1 degree The deviation from the perpendicular was <1 degree irradiating a grid mask with scattering from a piece of glassy carbon, 1.5 Å solution scattering from polystyrene latex solution scattering from polystyrene latex No spatial distortion was observed (110 nm, 5 mg / ml), 1.5 Å 2008/8/30 IUCr 2008 Osaka, Japan 19
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