X-Ray Detectors for Synchrotron Applications SRI 2012 satellite workshop

5 Jul 2012, 13:00 → 7 Jul 2012, 16:00 Europe/Zurich

F7 (ETH Zürich)

Bernd Schmitt (PSI)

© PSI

The SRI conference is the largest international forum for information exchange among scientists involved in development of new concepts, technologies and instruments related to synchrotron radiation research. Among the five satellite events planned both before and after SRI 2012, the Paul Scherrer Institut is organising a workshop on X-Ray detectors that will held at ETH Zurich.

The aim of the workshop is to bring together experts in synchrotron radiation detection and detector developers working in the field, and provide a comprehensive review of recent detector development activities and projects targeting both storage rings and XFEL applications. The workshop is organized in topical sessions that will be covered by invited speakers and will mainly focus on progress recently achieved or expected from new projects at detector labs and manufacturers. The topical sessions will also include presentations about application requirements with emphasis on limitations of the detector systems that are in use today at synchrotron radiation facilities.

The workshop topics are:

• Energy dispersive detectors
• Detectors for soft X-ray applications
• Direct detection 2D detectors for storage rings
• Area detectors for X-ray FELs
• Sensor and interconnect technologies
• Hard X-ray indirect detection

Deadline for registration is 15^th of June.

Sponsors:

Thursday 5 July

13:00 → 14:00 Registration

14:00 → 15:35 Energy dispersive detectors

14:00 Welcome

14:10 Development of an energy resolving Multi-Element Germanium Detector at Diamond

With three beam lines and four end stations devoted to EXAFS experiments, absorption spectroscopy is one of the major experimental techniques available at Diamond Light Source. Energy resolving fluorescence detectors are the most used in EXAFS experiments with dilute elements and are the part that most often limits the performance of EXAFS beam lines. In this talk I will describe briefly the physical principle and detector requirements of EXAFS experiments. After that I will show how fluorescence detectors in use at Diamond try to meet such requirements. In particular the joint Diamond/STFC/Canberra development of a monolithic 64 elements germanium detector will be described as well as its performance. Finally a possible development envisaged to further improve detector performance is shown.

Speaker: Nicola Tartoni (Diamond Light Source)

Slides Tartoni_SRI_detector_workshop_final.pdf

14:35 Detector developments at BNL

The talk will describe ongoing work towards developing a range of new detectors for x-ray synchrotron radiation applications, and show results from some of these efforts.

Speaker: D Peter Siddons (Brookhaven National Laboratory)

Slides siddons_sri2012.pdf

15:00 Development of energy dispersive detectors at STFC

A hyperspectral imaging detector for high energy X-rays has been developed at STFC as part of the UK wide HEXITEC collaboration. The HEXITEC detector uses CdTe or CdZnTe with 80x80 pixels on a 250µm pitch. Each pixel is gold stud and silver epoxy bump bonded onto the HEXITEC ASIC which has a set of identical electronics to readout the energy of every photon detected in the sensor from 4keV to 200keV. The pixel electronics contain a charge sensitive pre-amplifier with leakage current compensation; a two stage shaping amplifier and a peak hold circuit. The peak hold voltages, which are directly proportional to the energy of the detected photons, are sequentially readout using a rolling row readout method with a frame rate of 10kHz. The voltages are digitized and have some basic processing in a data acquisition system before being sent to a dedicated PC over base camera link. The data is calibrated and charge sharing corrections are applied to the data to allow the best energy resolution to be obtained. With 1mm thick Schottky contact CdTe an average pixel energy resolution (FWHM) of 0.8keV at 60keV is achieved with room temperature operation. To be able to identify and correct the charge sharing events there needs to be ≈10% or fewer pixels with an event in anyone frame. This dictates that the maximum number of photons that can be measure with high energy resolution is limited to 10million photons/80x80 detector/second. The HEXITEC 80x80 detector has an active area of 2x2cm but it can be butted on three sides. Results from a 2x2 tiled array of HEXITEC detectors will be presented as well as designs for larger area detectors using the three side buttable design. Four side buttable HEXITEC ASICs have been manufactured with a post processing method of forming thru silicon vias to place the wire bond pads on the back side of the ASIC. The processing method and results and the HEXITEC ASICs will also be presented.

Speaker: Mr Matt Wilson (STFC Detector Development Group)

Slides Energy_Dispersive_Detectors_Matt_Wilson.pdf

15:25 Industrial Presentation: Silicon Drift Detectors for X-ray spectroscopy applications – present and future

In recent years, SDD detectors have become indispensable for a large variety of industrial and research applications. Featuring the monolithical integration of the first FET onto the detector, the SDDs manufactured by the companies PNSensor and PNDetector in Munich have established themselves as high resolution, high throughput energy dispersive detectors for X-ray Fluorescence (XRF) or X-ray microanalysis instrumentation. The classic silicon drift detector with active area from 5 to 100 mm2 shows good energy resolution down to 130 eV at Mn-Ka and very high count rate capability. Often equipped with a Beryllium window, the detectors are well suited for all kinds of Energy Dispersive Spectroscopy (EDS) specifically in XRF analysis. As the good energy resolution is even achieved at -10°C, the detectors are very interesting for applications where the cooling power is limited, e.g. for battery operated Hand-Held instruments. Spectroscopic measurements with large area detectors of 60 and 100 mm2 will be shown. For applications requiring the ultimate energy resolution, the Silicon Drift Detector Droplet (SD3) becomes the first choice. Due to its special geometry which further reduces the input capacitance down to 50 fF, this detector type leads the SDD performance very close to the physical limits, e.g. energy resolution with 122 eV FWHM @ MnK at count rates of 100 kcps. Its excellent light element performance (e. g. 38 eV @ B_K) makes this detector very suitable for high resolution EDS as for Microanalysis in Scanning and Transmission Electron Microscopes (SEM and TEM). The SD3 detector is available in a compact housing with active area varying from 5 to 30mm2. Recent developments in terms of further minimizing the input capacitance with an optimized FET design including measurement results of optimized SDD devices will be presented. Very large area detectors with large solid angle coverage are often mandatory for many scientific applications like in synchrotron experiments. Whereas single cell SDD modules are available up to an active area of 100 mm2, for significantly larger active areas monolithical arrays of SDDs are the first choice. Moreover, multichannel SDD arrays can also cope with much higher count rates than the single devices, which again make them very attractive for synchrotron applications where the count rate values can be driven very high. Multielement SDD modules with total active areas up to 600 mm2 combining a number of 3, 4, 6 or 7 cells, with energy resolution values down to 130 eV and count rate capability of up to 5x106 cps are available in various package configurations. New spectroscopic measurements with a 6x100 mm2 SDD detector will be reported.

Speaker: Dr Adrian Niculae (1. PNDetector GmbH, Otto-Hahn-Ring 6, 81739 Munich, Germany)

15:35 → 16:00 Coffee Break

16:00 → 18:00 Soft X-ray area Detectors

16:00 Requirements from Synchrotrons

Speaker: Dr Thorsten Schmitt (Paul Scherrer Institut)

Slides Requirements_Soft_X_Ray_CCD_RIXS_Schmitt.pdf

16:25 Development of soft X-ray area detectors at DESY

With the increased brilliance of state-of-the-art Synchrotron radiation sources and the advent of Free Electron Lasers enabling revolutionary science with EUV to X-ray photons comes an urgent need for suitable photon imaging detectors. With both Petra III and FLASH at DESY providing unique opportunities for experiments (also) with soft X-ray beams, DESY's Photon Science Detector Group is developing sensors to meet the diverse range of requirements presented by their users. These include a demand for soft X-ray area detectors with high frame rates, very large dynamic range, single-photon resolution with low probability of false positives, and (multi)-megapixels. Beyond involvement in the DSSC and Gotthard developments, as well as participation in the CAMP instrument, DESY is leading a collaborative effort with RAL and Elettra to develop the "Pixelated Energy Resolving CMOS Imager, Versatile and Large", short PERCIVAL, to fulfill the demand for high-performance soft-X-ray imagers. PERCIVAL is a monolithic active pixel sensor (MAPS), i.e. based on CMOS technology. It will be back-thinned to access its primary energy range of 250 eV to 1 keV with target efficiencies above 90%. According to its preliminary specifications, the roughly 10x10cm^2, 4k x 4k monolithic sensor will operate at frame rates up to 120 Hz (commensurate with most FELs) and use multiple gains within its 25 micron pixels to measure 1 to ~ 10^5 (500eV) photons. Small-scale prototype systems are currently being manufactured. We will present the projected PERCIVAL performance parameters and project timeline. Continued input from the community is looked for during the workshop.

Speaker: Dr Cornelia Wunderer (DESY)

Slides 2012-07-05_Wunderer_SoftXrayDetectorsDESY.pdf

16:50 Soft X-ray Detector Developments at Berkeley

The Advanced Light Source is a predominantly soft X-ray storage ring facility, where needs for higher speed and higher efficiency pixilated detectors has driven our activities. We have developed 100s of Megapixel per second (MPix/s) direct X-ray detectors based on CCDs grown on thick, high-resistivity silicon along with a custom readout circuit (fCRIC) in 0.25 μm CMOS. Initial versions of these FastCCDs with 30 μm pixels have been used at the ALS to demonstrate soft X-ray ptychography and white light Laue microdiffraction. They are also in use at the APS for photon correlation spectroscopy and at the LCLS for resonant inelastic scattering . A new, larger format version has been developed, and is planned for use at ALS, APS, LCLS and Eu XFEL. A 10,000 MPix/s direct detection CCD is in development, based on a column parallel CCD with 30 x 50 μm2 pixels, and a custom readout circuit (HIPPO ) in 65 nm CMOS. The core of the HIPPO consists of a 12-bit, 80 MSPS ADC, which is used with four multiplexed inputs to allow correlated double sampling at 10 MHz. Each CCD column is connected to a low-noise charge-sensitive preamplifier , which, together with the ADCs, are on a 50 μm pitch. Associated developments include fine pitch (5 μm) direct detection CCDs for spectroscopy, together with Active Pixel Sensors in bulk CMOS and Silicon-on-Insulator. In all of these cases, thin conductive entrance windows are required, and we have been developing low-temperature processes (which can be used after the other detector processing steps have taken place). A simple and robust technique for 1,000 Å thick contacts has been developed, and work is on-going for 50-100 Å thick contacts.

Speaker: Dr Peter Denes (Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA)

Slides 201207_SRI_DenesR.pdf

17:15 Absolute calibration of X-ray detectors at low energies

For quantitative measurements, absolutely calibrated detectors are required. In the X-ray and soft X-ray range down to about 0.2 keV, two different approaches can be realized for energy-dispersive detectors like Si(Li) detectors, CCDs or Silicon Drift Detectors (SDDs): the calibration in the calculable undispersed radiation of a primary source standard, or the calibration against a primary detector standard. - The electron storage ring BESSY II in Berlin is used by PTB as primary source standard. All parameters which are relevant for the calculation of the emitted radiation are determined with high accuracy. For detector calibration, BESSY II is operated with only a few stored electrons. - A cryogenic electrical substitution radiometer serves as primary detector standard. The calibration requires monochromatic radiation of high spectral purity. This approach is also used to calibrate non-energy dispersive detectors like semiconductor photodiodes. These calibrated photodiodes are employed as transfer detector standards to calibrate other detectors as e. g. the hybrid-pixel Pilatus detector. With both calibration approaches, relative uncertainties of about 1 % can be achieved for the detection efficieny or responsivity. References: Calibration and characterization of semiconductor X-ray detectors with synchrotron radiation M. Krumrey, M. Gerlach, F. Scholze and G. Ulm Nucl. Instr. and Meth. A 568, 364 – 368 (2006) The PTB high-accuracy spectral responsivity scale in the VUV and X-ray range A. Gottwald, U. Kroth, M. Krumrey, M. Richter, F. Scholze and G. Ulm Metrologia 43, S125 – S129 (2006)

Speaker: Dr Michael Krumrey (Physikalisch-Technische Bundesanstalt)

Slides Krumrey_SRI_Det_Zurich.pdf

17:40 Industrial Presentation: Recent and coming products from RoentDek

We will present our current single particle/photon counting area detector technology based on microchannel-plate devices with position and time sensitive delay-line anode readout. These detectors are widely used at synchrotron facilities for means of correlated particle detection and for single particle/photon imaging at low intensity level. Recent developments focus on applying this detection technique to the VUV to X-ray regime.

Speaker: Dr Ottmar Jagutzki (RoentDek GmbH)

Slides RoentDek.pdf

18:45 → 20:00 Guided City Tour

Friday 6 July

09:00 → 10:40 Direct detection area detectors for storage rings I

09:00 Detector needs for x-ray diffraction experiments at synchrotron sources

X-ray diffraction is characterized by a rapidly decaying signal in reciprocal space which requires a large dynamical range for its detection. Besides this common feature, the ideal detector features may differ depending on the nature of different experiments, like for example Small Angle X-ray Scattering, Protein Crystallography, and Coherent Diffraction Imaging. Additionally, scanning schemes over large samples, radiation damage, and time-resolved experiments impose further constraints in the required time resolution and readout speed. Here we present a summary of the required characteristics of X-ray detectors for diffraction measurements in synchrotron sources, with an especial focus on the research performed at the Swiss Light Source.

Speaker: Dr Ana Diaz (Paul Scherrer Institut)

Slides 2012-07-06_detectors_workshop_revised_Ana_Diaz.pdf

09:25 Eiger, a fast framing, large area pixel detector for X-ray applications

Eiger is a single-photon counting X-ray pixel detector being developed at the Paul Scherrer Institut for applications at synchrotron light sources. It follows the widely utilized and successful Pilatus detector. The major advantages over the Pilatus system are the smaller pixel size (75 μm), higher frame rate capability (22 kHz) and negligible readout dead time (4 μs). These enhanced features will directly benefit many fields at synchrotron sources, especially research in the fields of Protein Crystallography, Small Angle X-ray Scattering, Coherent Diffraction Imaging and X-ray Photon Correlation Spectroscopy. The presentation will cover the details of the Eiger and our progress towards large area detector systems. Measurements that characterize the detector like the energy range, rate capabilities, threshold dispersion and radiation tolerance will also be addressed. In conclusion, highlights from experiments will be reported.

Speaker: Dr Ian Johnson (PSI)

Slides SRI_2012_ij.pdf

09:50 Design and fabrication of EXCALIBUR detector modules

The EXCALIBUR detector is a small-pixel photon counting area detector developed by the Diamond Light Source and the Science and Technology Facility Council in the UK for coherent X-ray diffraction. EXCALIBUR is based on the 55 micron pixel size read-out ASIC developed by the MEDIPIX3 collaboration. This talk describes the geometry of EXCALIBUR modules consisting of 16 MEDIPIX3 ASICs bump-bonded to a large silicon sensor die. The design of the hybrid carrier board and flexi-rigid circuits interfacing the hybrid pixel detector to FPGA boards will be presented as well as the strategy for controlling the temperature of the module. A description of module fabrication and quality control procedures at every step of the fabrication process will be provided. X-ray images obtained with an EXCALIBUR detector module will be presented together with the acquisition set-up developed for the transfer of 3M-pixel images produced by the final 3-module detector assembly at a frame rate of 100 frames per second in continuous mode and 1000 frames per second in burst mode.

Speaker: Dr Julien Marchal (Diamond Light Source)

Slides jmarchal_SRI2012_workshop.pdf

10:15 Detector Developments at Cornell

A variety of pixel array detectors (PADs) under development at Cornell are described. Analog integration of the x-ray induced signal has been used extensively within the pixels of these detectors to allow for imaging with x-ray fluxes which would exceed photon counting limits. Using analog integration, however, does not preclude imaging with single photon sensitivity. High quality imaging can be demonstrated using data sets with fluences of only a few photons per frame. Detector projects include devices for single bunch imaging as well as a device with an extended dynamic range utilizing an overflow counter with pixel reset. An additional project is underway which will use a highly parallel data stream between the detector chip and a field programmable gate array (FPGA) to allow customizable pixel-level data processing such as computation of the time autocorrelation function on time scales as short as 100 ns.

Speaker: Dr Mark Tate (Cornell University)

Slides tate_Zurich2012e.pdf

10:40 → 11:00 Coffee Break

11:00 → 12:10 Direct detection area detectors for storage rings II

11:00 Industrial Presentation: X-Ray photon counting detectors from imXPAD

The imXPAD company was launched in May 2010 for the design and fabrication of “XPAD” hybrid pixel detectors. The company is now producing different sizes of XPAD silicon detectors, from 7.5 x 1.5 cm2 to 15 x 15 cm2. Number of detectors have already been delivered to synchrotrons (SOLEIL, ESRF, ALBA,…) and laboratories (CRM2 Nancy France, ECP Paris France, Xenocs Grenoble France…). Special requirements like vacuum compatible or U-shape detectors can also be satisfied. For high energy X-rays, special conversion crystals like CdTe and GaAs are under study and will be available by the end of the year. The status of the imXPAD company will be given and the XPAD detectors will be described as well as typical experiments.

Speaker: Mr vasse laurent (imxpad)

Slides SRI-2012-Présentation_.pdf SRI-2012-Présentation_.pdf (Protected)

11:10 The LAMBDA photon counting pixel detector

Single-photon-counting pixel detectors are the cutting-edge technology in a range of scattering and imaging experiments at synchrotrons. The Medipix3 readout chip has a number of novel features that are attractive for synchrotron experiments: a high frame rate with zero dead time, high spatial resolution, and a “charge summing” feature that can improve image quality. Using this readout chip, DESY are developing a large-area Medipix3-based detector array (LAMBDA). A single LAMBDA module consists of 2 by 6 Medipix3 chips on a ceramic carrier board, bonded to either a single large silicon sensor or two smaller high-Z sensors. The readout electronics are placed behind the sensor, allowing tiling of multiple modules. The readout electronics consist of a signal distribution board, which provides services to the detector head such as powering, and a readout board, which uses an FPGA to control the detector head and communicate with a control PC. Currently, the first large silicon modules have been constructed and read out with a prototype readout board, and we are working on the hardware and firmware for a high-speed readout system based on 10-Gigabit Ethernet links. One limitation of standard silicon hybrid pixel detectors is their poor quantum efficiency at higher photon energies. In collaboration with Canberra France Specialty Detectors, we are developing a germanium hybrid pixel detector for use on higher-energy beamlines. Although germanium needs to be cooled during operation, small-pixel photon counting detectors are much more tolerant of leakage current than large spectroscopic detectors, so cryogenic temperatures are not need. Canberra have produced a set of 256-by-256-pixel planar germanium sensors with 55µm pitch, and these have been bonded to Medipix3 readout chips by Fraunhofer IZM (Berlin). These first germanium hybrid pixel detectors are currently being tested.

Speaker: Dr David Pennicard (DESY)

Slides SRIDetWorkshop_Lambda_DPennicard_public2.pdf

11:35 CdTe pixel and strip detector developments at SPring-8

This study describes CdTe pixel and strip detector developments for high energy X-ray diffraction experiments at SPring-8. Pixel-readout ASICs (SP8-01 and SP8-02) have been developed for the pixel detector, where each pixel has a preamplifier, a shaper, a window comparator, and a 20-bit counter. The analog circuit was characterized with a fast setting of 100 nsec and a dynamic range from 10 keV to 100 keV. The window comparator has advantage to avoid electric noise and fluorescent X-ray background by the lower threshold and higher-harmonics beam contamination by the upper threshold. MYTHEN ASIC, which developed at PSI, was applied as the strip detector’s readout electronics. We have fabricated Pt/CdTe/Al-pixel/strip sensors performing a Schottky diode detector with electron-readout operation. This electrode-metal configuration realized a low leakage current and a long-term stability in near room temperature. The presentation will describe the features of SP8-02 ASIC forming the 200 um x 200 um pixel size with the 20 x 50 matrix. The Pt/CdTe/Al sensor performance will be also discussed in comparison with Pt/CdTe/Pt and In/CdTe/Pt sensors.

Speaker: Dr Hidenori Toyokawa (Japan Synchrotron Radiation Research Institute)

Slides SRI_satellite_Hidenori.pdf

12:00 Industrial Presentation: The New PILATUS3 ASIC with Instant Retrigger Capability

A novel photon counting method for non-paralyzable counting and its implementation in the new PILATUS3 ASIC are presented. Pulse pile-up significantly affects the observed count rate at high photon fluxes in single-photon counting x-ray detectors and can lead to complete paralyzation of the counting circuit. In PILATUS single-photon counting hybrid-pixel x-ray detectors, count rate correction is applied in order to compensate for the counting loss at high count rates. However, counter paralyzation limits the maximum usable count rate of the PILATUS2 ASIC to typically 2*10^6 photons per second and pixel. In order to overcome this limitation, instant retrigger capability is introduced as a new photon counting method that results in non-paralyzable counting and achieves improved high-rate counting performance. The instant retrigger capability re-evaluates the pulse signal after a predetermined dead time interval after each count and potentially retriggers the counting circuit in case of pulse pile-up. The respective dead time interval is adjustable and accounts for the width of a single photon pulse. As a result, the counting becomes non-paralyzable and enhanced count rate correction can be applied in order to achieve improved data quality at high count rates. The new PILATUS3 ASIC features instant retrigger capability with adjustable dead time. The implementation of this new approach and experimental results are presented. The new ASIC additionally features counter overflow handling, improved pixel uniformity, reduced crosstalk, reduced readout time, and compatibility with CdTe sensors. With the new design, higher count rates can be measured and better data quality is achieved up to rates of more than 10^7 photons per second and pixel. Finally, the PILATUS3 product family based on the PILATUS3 ASIC and new high performance read-out electronics will be presented.

Speaker: Dr Teddy Loeliger (Dectris Ltd.)

Slides

• talk_sri12_satellite_120706.pdf
• talk_sri12_satellite_120706.pdf
• talk_sri12_satellite_120706.pdf
• talk_sri12_satellite_120706.pdf

12:10 → 12:35 Soft X-ray area Detectors

12:10 Development of low energy Detectors at Elettra

Most of the low energy imaging detectors used at Elettra are based on micro channel plates in combination with cross delay line technology, originally developed for time resolved photoelectron spectroscopy in conjunction with pump- and-probe systems. Due to the architecture of the acquisition electronics, the detector correlates each event (electrons or photons) with its arrival time accomplishing a time resolution conform to pump-and-probe experiments on the picoseconds scale for a global input rate of up to 4 Mcounts/s. Owing to the adjustment of its direct bandgap down to 0.8 eV quantum well (QW) structures have what it takes for low energy photon detection. QW structures are planar objects in which electrons are confined in one dimension. Compound semiconductors such as InGaAs / InAlAs can be used to fabricate QWs with several combinations of barrier and well materials, allowing for a tuning of the electron band gap in a wide spectral range. Depending on the external circuitry internal charge amplification mechanism can be applied for very low signal levels. Moreover, the high mobility of the charge carries allows the design of very fast photon detectors with response times in the pico second range and below. Spatial resolution can be obtained by lithographic segmentation. Primarily for beam diagnostics of segmented mono crystalline CVD diamond detectors have been developed that allow simultaneous monitoring of beam intensity and position even on a single bunch level for Elettra’s soft x-ray beam lines and on a single shot basis for the Fermi FEL.

Speaker: Dr Ralf Hendrik Menk (Sincrotrone Trieste, Italy)

Slides menk_SRI_KEY.pdf

12:35 → 13:30 Lunch

13:30 → 14:20 Interconnect and sensor technologies

13:30 Overview of interconnect technologies

Interconnection technologies are important for compact modern tracking detectors. Recently new developments come to the focus which allow a wide variety of new detector layouts and arrangements. Among these are fine pitch bump bonding with pitches down to 50µm and below and Through Silicon Via (TSV) conncetion through the electronics layer of hybrid pixel detector. Real 3D integration of several electronics layer is another attractive approach to compact the detector design. In this presentation on overview of these interconnection is given as they are currently tested for future particle physics tracking detectors.

Speaker: Dr Fabian Hügging (University of Bonn)

Slides Interconnects_SRI_0712.pdf

13:55 Current Status of high-Z detector materials

High-Z semiconductor materials have considerable potential for use as room temperature X-ray and gamma ray detectors, combining good spectral resolution with high quantum efficiency. For many years germanium has been the only readily available high-Z detector material, however recent improvements in compound semiconductor materials such as CZT means that room temperature high-Z detectors are now becoming commercially available. In this talk I will review the current and future status of high-Z detector materials, with a particular emphasis on the requirements for synchrotron instrumentation.

Speaker: Prof. Paul Sellin (University of Surrey)

Slides SELLIN_SRI_Workshop.pdf

14:20 → 15:35 XFEL detectors I

14:20 Detectors and Science at the European XFEL

This presentation will present some science examples and detector needs at different scientific instruments of the European XFEL

Speaker: Christian Bressler (European XFEL)

14:45 Development of the DEPFET Sensor with Signal Compression: a Large Format X-ray Imager with Mega-Frame Readout Capability for the European XFEL

We present the development of the DSSC: an ultra-high speed detector system for the European XFEL in Hamburg. The DSSC will be able to record X-ray images with a maximum frame rate of 4.5MHz. The system is based on a silicon pixel sensor with a DEPFET as a central amplifier structure and has detection efficiency close to 100% for X-rays from 0.5 keV up to 10keV. The sensor will have a size of 210x210 mm^2 composed of 1024x1024 pixels. 256 readout ASICs are bump-bonded to the detector in order to provide full parallel readout. The signals coming from the sensor are processed by an analog filter, digitized by 8-bit ADCs and locally stored in a SRAM. In order to fit the dynamic range of 10^4 photons of 1keV per pixel into a reasonable output signal range, achieving simultaneously single 1keV photon resolution, a strongly non-linear characteristic is required. The proposed DEPFET provides dynamic range compression at the sensor level. The most challenging property is that the single 1keV photon resolution and the high dynamic range are accomplished within the 220ns frame rate. The main building blocks and properties of the system will be discussed. The experimental characterization of first non-linear DEPFET will be presented. New experimental results obtained coupling this newly fabricated DEPFET prototype to an ASIC prototype which comprises the complete readout chain from the analog front-end to the ADC and the memory will be shown.

Speaker: Dr Matteo Porro (Max Planck Institut Halbleiterlabor)

Slides DSSC_Zurich_Porro.pdf

15:10 AGIPD, the Adaptive Gain Integrating Pixel Detector: A 4.5 MHz camera for the European XFEL

The European X-Ray Free Electron Laser (XFEL) [1,2] will provide ultra short, highly coherent X-ray pulses which will revolutionize scientific experiments in a variety of disciplines spanning physics, chemistry, materials science, and biology. One of the differences between the European XFEL and other free electron laser sources is the high pulse repetition frequency of 4.5 MHz. The European XFEL will provide pulse trains, consisting of up to 2700 pulses separated by 220 ns (600 µs in total) followed by an idle time of 99.4 ms, resulting in a supercycle of 10 Hz. Dedicated fast 2D detectors are being developed, one of which is the Adaptive Gain Integrating Pixel Detector (AGIPD) [3-5]. This development is a collaboration between DESY, the University of Hamburg, the University of Bonn (all in Germany) and the Paul Scherrer Institute (PSI) in Switzerland. AGIPD is based on the hybrid pixel technology. The current design goals of the newly developed radiation hard Application Specific Integrated Circuit (ASIC) with dynamic gain switching amplifier in each pixel are (for each pixel) a dynamic range of more than 104 12.4 keV photons in the lowest gain, single photon sensitivity in the highest gain, an analog memory capable of storing 352 images, and operation at 4.5 MHz speed. A vetoing scheme allows to maximize the number of useful images that are acquired by providing the possibility to overwrite any previously recorded image during the pulse train. It is necessary to store the acquired images inside the pixel logic during the pulse train and a compromise had to be found between storing many images, requiring a large pixel area, and high spatial resolution, requiring small pixels sizes. The AGIPD will feature a pixel size of (200 µm)2 and a silicon sensor with a thickness of 500 µm. The image data is read out and digitized between pulse trains. A project overview and a performance estimate will presented as well as results from the current test chips demonstrating the capabilities of the final system. References [1] M. Altarelli et al., Technical Design Report, ISBN 978-3-935702-17-1 (2006). [2] Th. Tschentscher et al, TECHNICAL NOTE XFEL.EU TN-2011-001 (2011), DOI:10.3204/XFEL.EU/TR-2011-001. [3] B. Henrich et al., Nucl. Instr. and Meth. A 663 2011 S11-14, DOI: 10.1016/j.nima.2010.06.107. [4] X. Shi et al., Nucl. Instr. and Meth. A 624(2) 2010 387-391, DOI: 10.1016/j.nima.2010.05.038. [5] G. Potdevin et al., Nucl. Instr. and Meth. A 607(1) 2009 51-54, DOI: 10.1016/j.nima.2009.03.121.

Speaker: Dr Julian Becker (DESY)

Slides 120706_JBecker_SRIsat.pdf

15:35 → 16:00 Coffee Break

16:00 → 18:05 XFEL detectors II

16:00 The LPD Detector Development

We present the latest status of the Large Pixel Detector (LPD) research and development program. The LPD is being developed by STFCs Detector Systems Centre for The European XFEL. To match the properties of the XFEL machine this detector system must be capable of operating with a high frame rate (4.5MHz), large dynamic range (1e^5 photons), while maintaining low noise (~1 photon). The system must also have a large memory depth (512) and the accompanying high rate data acquisition system (1.5 GB/s) with real time data sparsification. To increase efficiency of the memory available a veto system is also required for bad frames. These requirements have been realised through the development of a complete detector system, encompassing silicon detectors and ASIC through to DAQ and supporting electronics and mechanics. The LPD system is built around a 4096 pixel detector tile with 500um pixels. These units are butted together to form larger area sensors. Details will be presented on all system components.

Speaker: Mr Matthew Hart (STFC)

Slides Matthew_Hart_-_SRI_-_The_LPD_Detector_Development.pdf

16:25 Charge integrating silicon detectors for SwissFEL.

1D and 2D detectors based on charge integrating readout with automatic gain switching logic are being developed at PSI. The systems are designed to provide a dynamic range of 10^4 12keV photons, single photon resolution down to a photon energy of a few keV and a noise lower than 200 e.n.c.. The GOTTHARD 1D miscrostrip detector module, which is under commissioning, is composed of a printed circuit board, 10 readout chips for a total of 1280 channels at 50um pitch. A complete readout chain, from the high speed ADCs to a Gbit link for the data download to the control PC, is also integrated on the board. Frame rates up to 60kHz (continuous) and 1MHz (burst) are achievable with the system. The JUNGFRAU 2D detector, which is expected to be deployed in 2015, will have a 75 um pixel pitch and a modular construction similar to the (PSI developed) EIGER photon counting detector. Results from the characterization measurements of the GOTTHARD system and the design specifications of the JUNGFRAU detector will be reported.

Speaker: Aldo Mozzanica (Paul Scherrer Institut)

Slides mozzanica_SRI_workshop_r.pdf

16:50 Silicon-On-Insulator PHoton Imaging Array Sensor (SOPHIAS) for X-ray Free-Electron Laser

On behalf of SOPHIAS collaboration SPring-8 Angstrom Compact free-electron LAser (SACLA), which is the second X-ray free-electron laser (XFEL) facility after LCLS at SLAC National Accelerator Laboratory achieved laser amplification on June 7th, 2011. In the first user run of SACLA starting in March 2012, 25 proposals from domestic/international institutions will be conducted, where more than half of the proposals will use the currently deployed Multiport CCD (MPCCD) detectors. In this talk, we present the development status of the novel X-ray 2D detector, SOPHIAS, for SACLA to cover the scientific cases, where the currently deployed MPCCD detector does not able to reach. The pixel structure of SOPHIAS is based on multi-via concept; the closely spaced implant regions within a single pixel is used for signal charge division. Each implant region is connected to the readout circuitry by metal via. By connecting non-equal number of via metal, unpropotional charge collection will be possible. Large portion of the signal is transferred to high gain amplifier sensitive to small signal regime, whereas small portion of the charge is transferred to low gain amplifier. This pixel with size of 30 um square is realized by using silicon-on-insulator (SOI) sensor technology developed with KEK and Lapis Semiconductor Ltd. Last year, we have introduced stitching and backside processing onto KEK multi-project wafer run process. We have succeeded in manufacturing with an area of 66 mm x 30 mm by stitching 5 shots of reticule size. The production is carried out by 0.2 um FD-SOI CMOS technology. Handle wafer, which is the photodiode for x-ray detection, has backside implanted, laser-annealed, and aluminum coated surface so to shield the optical light without sacrificing the quantum efficiency. The handle wafer is made of floating zone silicon which enables us to fully deplete 500 um thick handle wafer. The characterization as well as the development of readout system of the sensor is now under progress.

Speaker: Dr Takaki Hatsui (RIKEN)

Slides 20120706_SRI_satellite_Hatsui5_part.pdf

17:15 Experience with Detectors at the LCLS

The LCLS (Linac Coherent Light Source) offers unique opportunities for photon science. To take full advantage of this, a corresponding suite of detectors must be made available to scientists. Progress towards this goal will be presented along with experience gained from operating within the LCLS environment. Specific topics such as radiation damage will be addressed. The status of currently installed detectors as well as future plans will be presented.

Speaker: Dr Chris Kenney (SLAC National Accelerator Lab)

17:40 Large area, high speed pnCCDs as imaging spectrometers for X-ray FEL experiments

Fourth generation accelerator-based light sources, such as EUV and X-ray Free Electron Lasers (XFELs), deliver ultra-brilliant (~1012-1013 photons per bunch) coherent radiation in femtosecond (~10 fs to 100 fs) pulses and, thus, require novel focal plane instrumentation in order to fully exploit their unique capabilities. As an additional challenge for detection devices, existing XFELs (FLASH, Hamburg, LCLS, Menlo Park, SACLA, Hyogo) cover a broad range of photon energies from the EUV to the hard X-ray regime for single shot experiments and experiments with frame rates from 5 to 120 Hz. In order to meet these challenges, the Max Planck Advanced Study Group (ASG) has designed the CFEL-ASG Multi Purpose (CAMP) chamber. It is equipped with specially developed photon and charged particle detection devices appropriate to cover large solid-angles. A variety of different experiments are supported, such as atomic, (aligned) molecular and cluster jets, particle injectors for bio-samples or fixed target arrangements. CAMP houses a novel, large-area, broadband (30 eV to 15 keV), high-dynamic-range, single-photon-counting and imaging X-ray detectors based on the pnCCDs with a format of 512 x 1024 pixel and a pixel size of 75 x 75 µm2 [1]. Results from various beamtimes at FLASH, LCLS and SACLA will be given and the operational experience will be summarized. A new instrument – actually under development – consists of 1024 x 1024 pixel arrays having a total, monolithic sensitive area per module of about 60 cm2. The devices are 4-side buttable with an insensitive gap of approximately 1.5 mm in between. The new mounting and thermal coupling allows for a thermal homogeneity and stability of about 1 K over the full area under operating conditions. Due to the double sided processing of the pnCCD chips the device is back illuminated with a thin radiation entrance window for photon energies with high QE from 30 eV up to 15 keV. The entrance window is covered with an optical light blocking filter with an attenuation of light between 200 nm and 900 nm of the order of 105. Each megapixel unit is an independent detector system with frame rate capabilities up to 400 frames per second and a noise floor of less than 5 electrons at the highest gain and 20 electrons at the lowest. In the spectroscopic mode (high gain) every pixel can cope with approx. 1 x 104 electrons in the low gain mode this can go up to 106 electrons per pixel. We will show the results of the improvement of charge handling capacity (CHC) in real experiments. The focus of the talk will be on the improvement of the performance of the pnCCDs over the last 18 months, in terms of noise, charge handling capacity, readout speed and the realization of very different focal plane configurations due to the new modular 4-side buttable concept of the X-ray camera.

Speaker: Dr Lothar Strüder (MPE, Semiconductor Laboratory)

19:00 → 20:00 Excursion to Uetliberg

20:00 → 23:00 Workshop Dinner

Saturday 7 July

09:00 → 09:50 Indirect detection

09:00 Detector requirements for synchrotron-based X-ray tomographic microscopy: A customized high-speed data interface for sub-second temporal resolution at TOMCAT

Synchrotron based X-ray tomographic microscopy (SRXTM) is a technique to unravel the 3D internal structure and composition of opaque samples in a non-destructive manner at the micrometer scale. Thanks to its versatility, it can be used to investigate a variety of specimens and dynamic processes, spanning a wide range of spatial, temporal and density resolutions as well as sample sizes. However, the versatility of the technique can be fully exploited only if the detector system is matched to the specific experiment. Detector requirements for SRXTM are discussed in the first part of the talk. The TOMCAT beamline at the Swiss Light Source has established itself as a cutting edge hard X-ray tomographic microscopy endstation for experiments on a large variety of samples, such a new materials, biomedical tissues and rare fossils. Part of our research program focuses on ultra-fast tomographic microscopy to address a wide range of time resolved applications and in-situ experiments. The goal is the acquisition of full 3D datasets at sub-second temporal resolution in a continuous mode, currently not possible. In fact, ultrafast detectors available on the market can easily acquire more than 1000 fps and store the data in an on-board RAM. Data transfer from the internal RAM to an external storage system occurs however mostly at significantly lower rates (typically 40 MB/s). This rate mismatch strongly limits the phenomena that can be studied. Often only few seconds of a process can be captured: a compromise between data quality and acquisition length is mostly required. To overcome these limitations, we are developing a new customized high-speed data interface enabling transfer rates as high as 8 GB/s, which will be presented in the second part of the talk.

Speaker: Dr Federica Marone (PSI)

Slides Marone_SRI_2012.pdf

09:25 State of the art X-ray imaging cameras

The indirect detection scheme is based on a converter screen, front-optics and an imaging camera. This low-cost and low-risk solution based on commercial components is used on all synchrotron radiation sources for beam visualization and beam movement monitoring, and intensively for imaging applications. The indirect detection systems require a compromise between these conflicting parameters: large field of view and spatial resolution; high stopping power and spatial resolution. Nowadays, off-the-shelf systems or components are widely spread within SR sources but have some limitations: DQE, resolution, speed, etc. New indirect detection systems require higher DQE, faster cameras, higher image definition, better contrast and radiation resistance design. The detector developments are then focused on efficient scintillators, 16Mpixels optics, radiation-hard optics for pink beam and white beam, and the integration of fast-imaging cameras. An overview of the technology and the various components will be discussed. The properties performances and potential applications of the ESRF components and off-the-shelf systems will be described.

Speaker: Dr Thierry MARTIN (ESRF)

Slides SRI-PSI2012-ThM.pdf

09:50 → 10:30 Coffee Break

10:30 → 11:20 Data acquisition and data handling

10:30 Data backend system for fast multi megapixel detectors

PSI develops a new data backend system for fast next generation 2-dimensional multi megapixel detectors for applications in tomography and cSAXS. The system will handle frame rates up to the KHz range and data rates up to 10 GByte/s and beyond. The backend system will support online quality control, initial data analysis and preview while it saves the pixel data to permanent storage in parallel. Next generation megapixel detectors like Eiger have a fully modular architecture. Hence the maximum data bandwidth available on the detector to the backend system scales linearly with the detector's pixel count. The newly developed system will match the detector's modular architecture and allows similar bandwidth scaling. We will present the overall system architecture and it's design guidelines like: To use standard server and IT components and no dedicated custom made hardware; to build a message-passing asynchronous multi process based parallel system and to use a scripting language for the top-level implementation. Additionally we'll show by which means we intend to achieve sustained loss-less transfer of UDP datagrams close to 10GbE wire speed between detector modules and backend system. This is crucial to enable the detectors' use at production-quality synchrotron beamlines like cSAXS or Tomcat at SLS.

Speaker: Mr Heiner Billich (Paul Scherrer Institut)

Slides HeinerBillich_DataBackendSystem_2012-07-07.pdf HeinerBillich_DataBackendSystem_2012-07-07.pptx

10:55 LIMA: a generic framework for 2D detector data acquisition

LIMA is a generic software Library for IMage Acquisition developed at the ESRF. Its main aim is to simplify the integration of an heterogeneous park of 2D detectors in large facilities by providing a common, high performance and control system independent software framework. Hardware optimisations in image manipulation are exploited whenever possible; the framework complements the eventually limited capabilities in the detector hardware with equivalent software alternatives. A modular design allows the extension of the library hardware interface and software functionality, including user-defined post-processing algorithms. Although still under development, LIMA is already deployed at the ESRF since more than 2 years, performing fast 2D data acquisition, basic processing/reduction and saving. An international collaboration was created spontaneously around LIMA, being adopted by 7 institutes and industrial suppliers. More than a dozen of detectors are currently integrated, half of them contributed by collaborating parties. The ESRF is in favour of pushing the existing collaboration towards a broader and more formalised development framework. Such developments would be oriented to make LIMA an even more easily accessible and usable tool, with the potential of becoming a standard for 2D detector manufacturers and the research community.

Speaker: Mr Homs-Puron Alejandro A. (ESRF)

Slides SRI-2012-XRDSW-AH-Lima-v6.ppt

11:20 → 11:30 Farewell