A single photon counting pixel detector system for synchrotron - PowerPoint PPT Presentation

A single photon counting pixel detector system for synchrotron radiation applications H. Toyokawa Japan Synchrotron Radiation Research Institute / SPring-8 Swiss Light Source / PSI SPring-8, Japan 2.4 GeV storage ring 8 GeV storage ring First beam: August 2001 First beam: March 1997 User operation: User operation: from October 1997 from October 2001 SPring-8 and the Switzerland's Paul Scherrer Institute (PSI) signed the MOU on May 1999 to promote advanced synchrotron radiation research. H. Toyokawa @ JASRI/SPring-8 STD6, Carmal, CA 2006/9/15

PILATUS project • PILATUS (Pixel Apparatus for the SLS) is a challenging project to develop a large area single photon counting pixel detector for synchrotron radiation experiments by the PSI. • SPring-8 has been taking a part in the PILATUS project since 2001, based on the MOU. • Outline of my talk: – Futures of existed detectors and Mt. PILATUS pixel detectors – PILATUS-I with DIMILL technology – PILATUS-II with 0.25 µ m technology – Summary and outlook H. Toyokawa @ JASRI/SPring-8 STD6, Carmal, CA 2006/9/15

Existed 2D detectors for Synchrotron Radiation Applications • Position sensitive 2D detectors are powerful devices for use in synchrotron radiation experiments. Imaging plates are representative of them, and CCD-based detectors have become a major tool for protein crystallography recently. • These detectors, however, record X-ray intensity by integrating the energy deposited by X-ray photons. • Conventional Si, Ge, and NaI detectors are still essential instruments, when fluorescence background has to be rejected by energy discrimination. • The readout time of CCD is in the second range, and that for imaging plate is minutes. It is often so inefficient and so time consuming. H. Toyokawa @ JASRI/SPring-8 STD6, Carmal, CA 2006/9/15

Advantage for Pixel Detector • In this respect, the single photon counting pixel detector is regarded as a new generation of X-ray detectors. The most important features are the following. – No dark current, no readout noise and energy discrimination, resulting in maximum dynamic range. – High quantum efficiency. – Short readout time. X-rays on detector 0.2 mm E X-rays Pixel sensor Integrating detector Q 0.2 mm 0.3 mm ADC Sensor t Single photon counting detector Chip CMOS readout V Threshold Amplifier chip Bump Bonds output V Counter Comparator output H. Toyokawa @ JASRI/SPring-8 STD6, Carmal, CA 2006/9/15

PILATUS-I • The developed pixel detector consists of a number of detector modules. The 1 st module (PILATUS-I SMD) has been • developed in August 2001, and the 1M pixels large area detector with 3 × 6 modules in November 2003. • Although the PILATUS-I detector was a prototype with about 5% defective pixels in the readout chip (PILATUS-I chip) due to the DMILL technology, it realized a sufficiently high performance to allow the methodological study of its fields of applications. • We could study how to integrate the detector, how to operate in synchrotron radiation applications and how to analyze the data. H. Toyokawa @ JASRI/SPring-8 STD6, Carmal, CA 2006/9/15

Single Module Detector with Pilatus I Chip • An array of 2 × 8 custom CMOS readout chips is indium bump- bonded to the sensor. • Each pixel contains a charge-sensitive amplifier, a single level discriminator and a counter. An individual pixel is thus capable of being operated in a single photon counting mode. single module 366 x 157 pixels Area: 81 x 36.6 mm 2 16 chips Readout time: 6.7ms @ 10 MHz up to 30 frames/sec H. Toyokawa @ JASRI/SPring-8 STD6, Carmal, CA 2006/9/15

Two-dimensional Time-resolved X-ray Diffraction Study of Directional Solidification in Steels at BL46XU M. Yonemura, T. Osuki, Corporate Research and Development Laboratories, Sumitomo Metal Industries H. Terasaki, Y. Komizo, Power:10V, 150A Silicon pixel detector Silicon pixel detector Joining and Welding Research Institute, Osaka University M. Sato, H. Toyokawa Japan Synchrotron Radiation Research Institute Torch scan （ ～ 1mm/s) 2 θ =35 ° Arc discharge In situ characterization of directional solidification process during welding was X-ray beams （ 18KeV ） carried out using the time resolved X-ray θ =20 ° Specimen （ 12mmt ） diffraction technique with the PILATUS-I SMD. The crystal growth during the rapid cooling was caught in detail and employed a To cooling tower systematic peak profile analysis in order to Cooling water Water-cooled copper plate acquire the essential information for controlling the weld microstructure. Then, high frame rate measurements up to 100 fps were performed with the PILATUS-II SMD. Data is under analysis. H. Toyokawa @ JASRI/SPring-8 STD6, Carmal, CA 2006/9/15

Time- -resolved diffraction pattern of the Fe resolved diffraction pattern of the Fe- -0.05C alloy 0.05C alloy Time (c) ～ 600 ℃ α 211 γ 311 γ 220 α 211 (d) ～ 500 ℃ α 220 δ 220 → γ 220 α 200 γ 311 (e) ～ 400 ℃ (b) ～ 1450 ℃ α 211 α 220 γ 220 α 200 A single-phase γ -Fe region first appears at about 1450 ℃ . Then the diffraction pattern shifts to a higher angle suggesting an improvement of crystallinity. The transformation from γ -Fe to α -Fe occurs at about 600 ℃ . γ -Fe and α -Fe co-exists until about 500 ℃ . H. Toyokawa @ JASRI/SPring-8 STD6, Carmal, CA 2006/9/15

Diffraction patterns from :[(GaAs)7/(AlAs)3] × 100 Pixels are individually addressable, and each pixel has a 4- or 6-bit threshold trim adjustment DAC, which can be set to minimize threshold dispersion across the chip. We demonstrated to discriminate low energy fluorescence X-ray below a detective threshold equalized to 15 keV by scattered X-rays with monochromatic beams at the BL46XU using the PILATUS-I SMD. Diffraction spots are a Bragg reflection peak and its higher orders. In addition, some powder diffraction circles are obtained from an aluminum base plate. The left figures show the result of the threshold of 10 keV, where week scatterings are smeared out on the interference background. In the 15 keV threshold result described as the right figures, on the other hand, higher order peaks are clearly seen. Threshold = 10 keV Threshold = 15 keV H. Toyokawa @ JASRI/SPring-8 STD6, Carmal, CA 2006/9/15

PILTUS–I chip • The PILATUS-I chip with 44 × 78 pixels was fabricated in the radiation tolerant DMILL 0.8 µ m CMOS process, and even fully screened chips showed 5 % defective pixels. • A subtle design oversight also caused the counters in the pixels to miscount under some circumstances. Row Select SR Col Select SR Ext/Comp Treshold Clock correction - 15 bit Global Φ 12 Comp SR + Tresh Clock counter Bump Gen Pad CS Calibrate ReadbackI Amp Ext Gate Rowsel & Clock 1.7fF Pixsel Colsel Pixsel DOUT AOUT Cal Digital Block Analog Block H. Toyokawa @ JASRI/SPring-8 STD6, Carmal, CA 2006/9/15

PILATUS-II chip architecture selection Row Rowsel selection Coloumn PILATUS II Chip: 60 cols, 97 rows DIN DOUT DCAL AOUT Colsel PILATUS II Pixel Cell ENA Pixsel DCLK 6 Bit Latch Pixsel - + DAC CNT/RO CHSEL Pulse Global Comp 20 bit φ 1 - + Shaper φ 2 Tresh Counter Bump Gen Pad CS Amp Pixsel Pixsel 1.6fF Rowsel & Pixsel Pixsel CAL AOUT ENA DIN Colsel DOUT DCLK H. Toyokawa @ JASRI/SPring-8 STD6, Carmal, CA 2006/9/15