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Synchrotrons and modern FEL light sources operate with bunch repetition rates in the MHz range. The profile of the electron beam inside the accelerator can be characterized with indirect experimental techniques where linear array detectors are employed to measure the emitted synchrotron radiation or the spectrum of a near-IR laser. To improve the performance of modern beam diagnostics we have developed KALYPSO, a detector system operating with a continuous frame rate of up to 2.7 MHz. To facilitate the integration in different experiments, a modular architecture has been adopted. Different semiconductor micro-strip sensors can be connected to front-end ASICs to optimize the quantum efficiency at different photon energies, ranging from visible light up to near-IR. The front-end electronics are integrated within an heterogeneous DAQ consisting of FPGAs and GPUs, which allows scientists to implement real-time data processing algorithms. The current version of the detector is in operation at the KARA synchrotron light source and at the European XFEL. In this contribution we present the detector architecture, the performance results and the on-going technical developments.

Gotthard-II is a charge-integrating microstrip detector developed for experiments and diagnostics at free-electron lasers using hard X-rays of 5 keV - 20 keV. Thanks to its excellent single photon sensitivity, large dynamic range as well as high frame rate of 4.5 MHz in burst mode, its potential scientific applications include X-ray absorption/emission spectroscopy, hard X-ray high resolution single-shot spectrometry (HiREX), beam diagnostics, as well as veto signal generation for pixel detectors. The Gotthard-II ASIC has been designed and fabricated using UMC-110 nm technology. The final ASIC design and performance in terms of noise, linearity, dynamic range, coupling between channels and speed will be discussed in the paper. In addition, a first measurement of an X-ray absorption spectrum of a standard copper sample has been done. The performance of the Gotthard-II in an experiment using energy dispersive X-rays has been demonstrated., 25 pages, 16 figures

JUNGFRAU is the pixel detector developed at PSI for SwissFEL [1]. Although the detector development was driven by the SwissFEL requirements, it was soon realized that such a detector could also be ...

The accuracy of X-ray diffraction data is directly related to how the X-ray detector records photons. Here we describe the application of a direct-detection charge-integrating pixel-array detector (JUNGFRAU) in macromolecular crystallography (MX). JUNGFRAU features a uniform response on the subpixel level, linear behavior toward high photon rates, and low-noise performance across the whole dynamic range. We demonstrate that these features allow accurate MX data to be recorded at unprecedented speed. We also demonstrate improvements over previous-generation detectors in terms of data quality, using native single-wavelength anomalous diffraction (SAD) phasing, for thaumatin, lysozyme, and aminopeptidase N. Our results suggest that the JUNGFRAU detector will substantially improve the performance of synchrotron MX beamlines and equip them for future synchrotron light sources. published

Ultrafast Imaging and Tracking Instrumentation, Methods and Applications Forum 2018, ULITIMA 2018, Argonne, IL, USA, 11 Sep 2018 - 14 Sep 2018; Nuclear instruments & methods in physics research / A Accelerators, spectrometers, detectors and associated equipment Section A 942, 162324 - (2019). doi:10.1016/j.nima.2019.06.065, The European XFEL is an extremely brilliant Free Electron Laser Source with a very demanding pulse structure: trains of 2700 X-Ray pulses are repeated at 10 Hz. The pulses inside the train are spaced by 220 ns and each one contains up to $10^{12}$ photons of 12.4 keV, while being $\rm \leq 100$ fs in length.AGIPD, the Adaptive Gain Integrating Pixel Detector, is a hybrid pixel detector developed by DESY, PSI, and the Universities of Bonn and Hamburg to cope with these properties. It is a fast, low noise integrating detector, with single photon sensitivity (for $E_{\gamma} \gtrapprox 6$ keV) and a large dynamic range, up to $10^4$ photons at 12.4 keV. This is achieved with a charge sensitive amplifier with 3 adaptively selected gains per pixel. 352 images can be recorded at up to 6.5 MHz and stored in the in-pixel analogue memory and read out between pulse trains. The core component of this detector is the AGIPD ASIC, which consists of $64 \times 64$ pixels of 200 µm $\times$ 200 µm. Control of the ASIC's image acquisition and analogue readout is via a command based interface. FPGA based electronic boards, controlling ASIC operation, image digitisation and 10 GE data transmission interface AGIPD detectors to DAQ and control systems. An AGIPD 1 Mpixel detector has been installed at the SPB experimental station in August 2017, while a second one is currently commissioned for the MID endstation. A larger (4 Mpixel) AGIPD detector and one to employ Hi-Z sensor material to efficiently register photons up to $E_{\gamma} \approx $ 25 keV are currently under construction., Published by North-Holland Publ. Co., Amsterdam

Chromium compensated GaAs sensors have been characterized using the charge-integrating readout chip JUNGFRAU. Due to its low noise performance and 75 × 75 μm2 pixel size, JUNGFRAU enables a precise measurement of the charge (of either polarity) with a high spatial resolution. Several sensor parameters like dark current, noise and spectral performance as well as the charge transport properties of the electrons have been determined. The short lifetime of holes in GaAs:Cr gives rise to an effect where pixels adjacent to a pixel with a photon hit show a strong negative signal when being absorbed close to the readout electrode. This so-called `crater effect' has been simulated and allows an estimation of the hole lifetime in GaAs:Cr.

MÖNCH is a 25 µm-pitch charge-integrating detector aimed at exploring the limits of current hybrid silicon detector technology. The small pixel size makes it ideal for high-resolution imaging. With an electronic noise of about 110 eV r.m.s., it opens new perspectives for many synchrotron applications where currently the detector is the limiting factor, e.g. inelastic X-ray scattering, Laue diffraction and soft X-ray or high-resolution color imaging. Due to the small pixel pitch, the charge cloud generated by absorbed X-rays is shared between neighboring pixels for most of the photons. Therefore, at low photon fluxes, interpolation algorithms can be applied to determine the absorption position of each photon with a resolution of the order of 1 µm. In this work, the characterization results of one of the MÖNCH prototypes are presented under low-flux conditions. A custom interpolation algorithm is described and applied to the data to obtain high-resolution images. Images obtained in grating interferometry experiments without the use of the absorption grating G2 are shown and discussed. Perspectives for the future developments of the MÖNCH detector are also presented., Journal of Synchrotron Radiation, 23 (6), ISSN:0909-0495, ISSN:1600-5775

International audience; High-Z sensors are increasingly used to overcome the poor efficiency of Si sensors above 15 keV, and further extend the energy range of synchrotron and FEL experiments. Detector-grade GaAs sensors of 500 μm thickness offer 98% absorption efficiency at 30 keV and 50% at 50 keV . In this work we assess the usability of GaAs sensors in combination with the MYTHEN photon-counting microstrip readout chip developed at PSI. Different strip length and pitch are compared, and the detector performance is evaluated in regard of the sensor material properties. Despite increased leakage current and noise, photon-counting strips mounted with GaAs sensors can be used with photons of energy as low as 5 keV, and exhibit excellent linearity with energy. The charge sharing is doubled as compared to silicon strips, due to the high diffusion coefficient of electrons in GaAs.

Gotthard-II is a 1-D microstrip detector specifically developed for the European X-ray Free-Electron Laser. It will not only be used in energy dispersive experiments but also as a beam diagnostic tool with additional logic to generate veto signals for the other 2-D detectors. Gotthard-II makes use of a silicon microstrip sensor with a pitch of either 50 {\mu}m or 25 {\mu}m and with 1280 or 2560 channels wire-bonded to adaptive gain switching readout chips. Built-in analog-to-digital converters and digital memories will be implemented in the readout chip for a continuous conversion and storage of frames for all bunches in the bunch train. The performance of analogue front-end prototypes of Gotthard has been investigated in this work. The results in terms of noise, conversionngain, dynamic range, obtained by means of infrared laser and X-rays, will be shown. In particular, the effects of the strip-to-strip coupling are studied in detail and it is found that the reduction of the coupling effects is one of the key factors for the development of the analogue front-end of Gotthard-II., Comment: 22 pages, 26 figures

A detailed characterization of CMOS devices in a technology process with minimum channel length of 110 nm and manufactured by UMC is reported in this work. The devices were evaluated before and after exposure to X-ray from a 10 keV source, up to a Total Ionizing Dose (TID) of 5 Mrad. This study provides useful hints in the design of front-end systems for the readout of pixel radiation detectors in harsh radiation environment. The results shown in this work are the first step of an activity aiming at studying the effects of ionizing radiation on noise and static performance of the investigated technology.

JUNGFRAU (adJUstiNg Gain detector FoR the Aramis User station) is a two-dimensional hybrid pixel detector for photon science applications at free-electron lasers and synchrotron light sources. The JUNGFRAU 0.4 prototype presented here is specifically geared towards low-noise performance and hence soft X-ray detection. The design, geometry and readout architecture of JUNGFRAU 0.4 correspond to those of other JUNGFRAU pixel detectors, which are charge-integrating detectors with 75 µm × 75 µm pixels. Main characteristics of JUNGFRAU 0.4 are its fixed gain and r.m.s. noise of as low as 27 e− electronic noise charge (, Journal of Synchrotron Radiation, 23 (2), ISSN:0909-0495, ISSN:1600-5775

The 20th IEEE-NPSS Real Time Conference, RT2016, Padua, Italy, 5 Jun 2016 - 10 Jun 2016 ; 1-2(2016)., We developed an ultra-fast linear detector with a frame rate of up to 10 6 frames per second (fps) in order to improve the acquisition rate and the resolution of Electro-Optical Spectral Decoding (EOSD) setups currently installed at several light sources (ANKA, European XFEL, TELBE).The system consists of a detector board, an FPGA readout board and a high-throughput data link. The detector board mounts a single linear array sensor with 256 pixels and a 50 μ m pitch. InGaAs or Si sensors are used to detect near-infrared (NIR) or visible light. The GOTTHARD chip, developed at PSI, is used as charge-sensitive preamplifier. Four analog outputs, each one connected to 32 pixels through an analog multiplexer, operate at a maximum switching frequency of 33 MHz, resulting in a maximum frame rate of 10 6 fps.The analog outputs are digitized by a multi-channel ADC with 14 bits resolution. The data acquisition, the operation of the detector board and its synchronization with synchrotron machines are handled by the FPGA. The readout architecture is based on a PCI-Express high-throughput data link which allows continuous data acquisition at 450 MB/s when operating at a frame rate of 1 Mfps. The system is completed with a real-time data analysis module based on Graphics Processing Units (GPU) systems. We present the experimental measurements taken with a NIR laser operating at a repetition rate of 900 kHz, as well as the current performance in terms of frame rate and noise figures.

A high-frame-rate single-photon-counting pixel detector named Eiger and its suitability for X-ray photon correlation spectroscopy are described., Eiger is the next-generation single-photon-counting pixel detector following the widely used Pilatus detector. Its smaller pixel size of 75 µm × 75 µm, higher frame rate of up to 22 kHz, and practically zero dead-time (∼4 µs) between exposures will further various measurement methods at synchrotron sources. In this article Eiger’s suitability for X-ray photon correlation spectroscopy (XPCS) is demonstrated. By exploiting its high frame rate, complementary small-angle X-ray scattering (SAXS) and XPCS data are collected in parallel to determine both the structure factor and collective diffusion coefficient of a nano-colloid suspension. For the first time, correlation times on the submillisecond time scale are accessible with a large-area pixel detector.

The spatial resolution of a single-photon-resolving integrating system has been improved using a non-linear charge interpolation approach. The resolution limit for a 20 µm-pitch sensor is presented., A synchrotron beam has been used to test the spatial resolution of a single-photon-resolving integrating readout-chip coupled to a 320 µm-thick silicon strip sensor with a dedicated readout system. Charge interpolation methods have yielded a spatial resolution of σx ≃ 1.8 µm for a 20 µm-pitch strip.

A charge integrating readout chip for silicon strip sensors is currently under development at Paul Sherrer Institut. The goal of the project is to provide a readout system that can sustain, through charge integration and automatic gain switching, the instantaneous many-photon deposition typical of the forthcoming XFEL machines. Nevertheless, a charge integrating readout with single photon sensitivity presents several features that can be exploited in many Synchrotron source applications: the possibility of a higher position resolution, the high photon rate capabilities and the possibility to detect low energy photon. A prototype of the readout chip (ROC) has been integrated with a strip detector and with a dedicated DAQ electronic, and it has been tested at the SYRMEP beam line (ELETTRA, Trieste). This work presents the readout chip and shows the results of the beam line tests in terms of spatial resolution and rate capabilities.

Synchrotron radiation applications require detectors with a high sensitivity and a large dynamic range in order to study both the strong and weak features of the samples. Moreover, a high spatial resolution is necessary for imaging and diffraction studies. The photon counting technique is currently the best solution to these requirements but it presents some limitations which can only be partially overcome by technological improvements i.e. the count loss at high impinging intensities, due to the readout electronics shaping time, and the restrictions on the minimum pixel size, due to the charge diffusion in the sensor. In order to overcome both these limitations a new generation of charge integrating hybrid detectors with single photon sensitivity is being developed. These preserve the advantages of counting detectors and at the same time allow a processing of the analog information in order to enhance the spatial resolution and perform some spectral analysis. A comparison between purely counting and analog readout for 50 and 25 μ m pitch microstrip detectors is presented in terms of spectral reconstruction capability and spatial resolution.

A report on the characterization, calibration and performances of the MYTHEN photon-counting silicon microstrip detector at the powder diffraction station at the Swiss Light Source is given., The MYTHEN single-photon-counting silicon microstrip detector has been developed at the Swiss Light Source for time-resolved powder diffraction experiments. An upgraded version of the detector has been installed at the SLS powder diffraction station allowing the acquisition of diffraction patterns over 120° in 2θ in fractions of seconds. Thanks to the outstanding performance of the detector and to the calibration procedures developed, the quality of the data obtained is now comparable with that of traditional high-resolution point detectors in terms of FWHM resolution and peak profile shape, with the additional advantage of fast and simultaneous acquisition of the full diffraction pattern. MYTHEN is therefore optimal for time-resolved or dose-critical measurements. The characteristics of the MYTHEN detector together with the calibration procedures implemented for the optimization of the data are described in detail. The refinements of two known standard powders are discussed together with a remarkable application of MYTHEN to organic compounds in relation to the problem of radiation damage.

The JUNGFRAU detector is a charge integrating hybrid silicon pixel detector developed at the Paul Scherrer Institut for photon science applications, in particular for the upcoming free electron laser SwissFEL. With a high dynamic range, analogue readout, low noise and three automatically switching gains, JUNGFRAU promises excellent performance not only at XFELs but also at synchrotrons in areas such as protein crystallography, ptychography, pump-probe and time resolved measurements. To achieve its full potential, the detector must be calibrated on a pixel-by-pixel basis. This contribution presents the current status of the JUNGFRAU calibration project, in which a variety of input charge sources are used to parametrise the energy response of the detector across four orders of magnitude of dynamic range. Building on preliminary studies, the first full calibration procedure of a JUNGFRAU 0.5 Mpixel module is described. The calibration is validated using alternative sources of charge deposition, including laboratory experiments and measurements at ESRF and LCLS. The findings from these measurements are presented. Calibrated modules have already been used in proof-of-principle style protein crystallography experiments at the SLS. A first look at selected results is shown. Aspects such as the conversion of charge to number of photons, treatment of multi-size pixels and the origin of non-linear response are also discussed.

The Microstrip sYstem for Time rEsolved experimeNts (MYTHEN) detector is a silicon microstrip detector with single photon counting readout developed for powder diffraction experiments at the Swiss Light Source. A one-dimensional 30 k channels system covering 120° has been installed at the Material Science beamline and is being used for users operation since the end of 2007. Due to its massively parallel detection of X-rays and fast readout, it is optimized for time-resolved or dose–critical measurements that can be performed in fractions of a second on the whole angular range. The intensity of the synchrotron radiation source can be exploited thanks to the high counting rate capability. Promising results have been obtained also for other synchrotron radiation applications like imaging and pump-and-probe experiments. The detector characteristics will be described in detail and its outstanding performances will be shown.

This paper reports the measurements that have been performed both in the Silicon Detector Laboratory at the University of Insubria (Como, Italy) and at the Instituto Ricerche SOlari Locarno (IRSOL) to characterize a CMOS pixel particle detector as a visible light camera. The CMOS sensor has been studied in terms of Quantum Efficiency in the visible spectrum, image blooming and reset inefficiency in saturation condition. The main goal of these measurements is to prove that this kind of particle detector can also be used as an ultra fast, 100% fill factor visible light camera in solar physics experiments.

Replacing planar circuits with vertically integrated ones allows to increment circuit functionalities on a given silicon area, while avoiding some of the problems associated with aggressively scaled technology nodes. This is particularly true for applications likely to subject circuits to high doses of ionizing radiation (such of x-ray detectors to be used in synchrotron rings and Free Electron Lasers), since the degradation mechanisms of some of the innovative materials to be used in most recent nodes have not been fully characterized yet. In this paper, an evolution is presented for the readout ASIC of a pixelated x-ray detector to be used for such applications. The readout circuit is distributed in a stack of two vertically interconnected tiers, thus doubling the circuitry resident in each pixel without increasing the pixel pitch (and thus compromising spatial resolution of the detector). A first prototype has been designed and manufactured, using a commercial 130 nm CMOS technology. Design issues are discussed, along with preliminary characterization results.

MONCH is a hybrid silicon pixel detector based on charge integration and with analog readout, featuring a pixel size of 25×25 μm2. The latest working prototype consists of an array of 400×400 identical pixels for a total active area of 1×1 cm2. Its design is optimized for the single photon regime. An exhaustive characterization of this large area prototype has been carried out in the past months, and it confirms an ENC in the order of 35 electrons RMS and a dynamic range of ~4×12 keV photons in high gain mode, which increases to ~100×12 keV photons with the lowest gain setting. The low noise levels of MONCH make it a suitable candidate for X-ray detection at energies around 1 keV and below. Imaging applications in particular can benefit significantly from the use of MONCH: due to its extremely small pixel pitch, the detector intrinsically offers excellent position resolution. Moreover, in low flux conditions, charge sharing between neighboring pixels allows the use of position interpolation algorithms which grant a resolution at the micrometer-level. Its energy reconstruction and imaging capabilities have been tested for the first time at a low energy beamline at PSI, with photon energies between 1.75 keV and 3.5 keV, and results will be shown.

We present a spectrometer setup based on grating dispersion for hard x-ray free-electron lasers. This setup consists of a focusing spectrometer grating and a charge-integrating microstrip detector. Measurement results acquired at Linac Coherent Light Source are presented, demonstrating noninvasive monitoring of single-shot spectra with a resolution of 2.0×10(-4) ±0.3×10(-4) at photon energy of 6 keV with more than 95% transmission of the main beam.

The two-dimensional pixel detector JUNGFRAU is designed for high performance photon science applications at free electron lasers and synchrotron light sources. It is developed for the SwissFEL currently under construction at the Paul Scherrer Institut, Switzerland. The detector is a hybrid pixel detector with a charge integration readout ASIC characterized by single photon sensitivity and a low noise performance over a dynamic range of 104 12 keV photons. Geometrically, a JUNGFRAU readout chip consists of 256×256 pixels of 75×75 μm2. The chips are bump bonded to 320 μm thick silicon sensors. Arrays of 2×4 chips are tiled to form modules of 4×8 cm2 area. Several multi-module systems with up to 16 Mpixels per system will be delivered to the two end stations at SwissFEL. The JUNGFRAU full scale readout ASIC and module design are presented along with characterization results of the first systems. Experiments from fluorescence X-ray, visible light illumination, and synchrotron irradiation are shown. The results include an electronic noise of ~50 electrons r.m.s., which enables single photon detection energies below 2 keV and a noise well below the Poisson statistical limit over the entire dynamic range. First imaging experiments are also shown.

AGIPD is a hybrid pixel detector developed by DESY, PSI, the University of Bonn and the University of Hamburg. The detector is targeted for use at the European XFEL, a source with unique properties: a bunch train of 2700 pulses with> 1012 photons of 12 keV each, only 100 fs long and with a 220 ns spacing, is repeated at a 10 Hz rate. This puts up very demanding requirements: dynamic range has to cover the detection of single photons and extend up to > 104 photons/pixel in the same image, and as many images, as possible have to be recorded in the pixel to be read out between pulse trains. The high photon flux impinging on the detector also calls for a very radiation hard design of sensor and ASIC. The detector will consist of 16 Sensor modules arranged around a central hole for the direct beam. Each made of a single sensor bumpbonded to 2 × 8 readout chips of 64 × 64 pixels in a grid of 200μ pitch. Each pixel of these ASICs contains a charge sensitive preamplifier featuring adaptive gain switching, changing sensitivity in three ranges, and a buffer to provide correlated double sampling (in the highest sensitivity mode). Most of the pixel area, albeit, is used for an analogue memory to record 352 frames. It is operated in random-access mode: data containing bad frames can be overwritten and the memory can be used in the most efficient way. The readout between two bunch trains is arranged via 4 ports: Data from pixels of one row is read in parallel and serialised by 4 multiplexers at the end of the pixel columns and driven off-chip as differential signals. The operation of the ASIC is controlled via a three-line serial interface, using a command based protocol. It is also used to configure the chip's operational parameters and internal timings.

The European XFEL [1] will provide fully coherent, 100 fs X-ray pulses, with up to $10^{12}$ photons at 12 keV. The high intensity per pulse will allow recording diffraction patterns of single particles or small crystals in a single shot. Consequently 2D-detectors have to cope with a large dynamic range: detection from single photon to >; $10^{4}$ photons/pixel in the same image. An additional challenge is the European XFEL machine: an Electron bunch train with 10 Hz repetition rate, consisting of up to 2,700 bunches with a 220 ns spacing. Recorded images have to be stored inside the pixel during the bunch trains and readout in between. To meet these requirements, the European XFEL has launched 3 detector development projects. The AGIPD project is a collaboration between DESY, PSI and the Universities of Bonn and Hamburg. The goal is a 1024 × 1024 pixel detector, with 200 $\mu$m pixel size and a central hole for the primary beam. The ASIC operates in charge integration mode: the output of each pixels preamplifier is proportional to the charge from the sensor generated by the X-rays. The input stage of the pixel cells uses dynamically adjustable gains. The output signal is stored in an analogue memory, which has to be a compromise between noise performance and the number of images. This is operated in random access mode, providing means to overwrite bad frames for optimal use of the 352 memory cells per pixel, which have to be readout and digitized in the 99.4ms bunch gap. The detector will be built of 8 × 2 fully depleted monolithic silicon sensors with a 8 × 2 array of CMOS readout chips bump-bonded to these. Several prototypes of the readout ASIC have been produced. The results presented originate from the 16 × 16 pixel matrices AGIPD 0.2, which was bump-bonded to a pixel sensor, and AGIPD 0.3, which includes the intended control algorithm and a fast differential interface to the off-chip world.

The European XFEL [1] under construction in Hamburg will provide fully coherent, 100 fs long X-ray pulses, with 1012 photons at 12 keV. The high intensity per pulse will allow recording diffraction patterns of single particles or small crystals in a single shot. As a consequence the 2D detectors have to cope with a large dynamic range in the images (one to 104 photons/pixel). An additional challenge is the European XFEL machine: an Electron bunch train with 10 Hz repetition rate, consisting of up to 3,000 bunches with a 200 ns spacing. This means that recorded images have to be stored inside the pixel during the bunch trains and read out between bunch trains. In order to meet these requirements, the European XFEL has launched 3 detector development projects. The AGIPD project is a collaboration between DESY, PSI and the Universities of Bonn and Hamburg. The goal is a 1000 × 1000 pixel detector, with 200 μm pixel size and a central hole for the primary beam. The ASIC operates in charge integration mode: the output of each pixel preamplifier is proportional to the charge from the sensor generated by the X-rays. The input stage of the pixel cells will have dynamically adjustable gains. The output signal is stored in an analogue pipeline, which has to be a compromise between noise performance and the number of images. 200 to 400 images have to be readout and digitized in the 99.4 ms long bunch gap. The detector will be built of 2×8 fully depleted monolithic silicon sensors with a 2×8 array of CMOS readout chips bump-bonded to these. The interface electronics is designed to process 400 images in 99 msec, without compromising single photon sensitivity or the full dynamic range. Since the ASIC is the linchpin of the project, several MPW runs to test the different aspects in terms of radiation hardness, noise and adaptive switching are submitted. We will give a general overview and report on the current status.

Pilatus is a silicon hybrid pixel detector system for detecting X-rays in single photon counting mode. The PILATUS II chip, fabricated in a radiation tolerant design with a standard 0.25 mum CMOS process, was used to construct multichip modules with a size of 84 times 34 mm2 comprising 94'965 pixels. All calibrations and characterizations were carried out with monochromatic X-rays from a synchrotron source. In order to set any required threshold above the noise level between 2.14 keV and 22 keV the detector was calibrated with X-rays. An algorithm to adjust thresholds pixel-by-pixel and create trim files based on X-ray flat-field images was developed. The threshold dispersion was reduced from 343 eV to 36 eV by the means of trim files. An electronic noise of 447 eV has been measured. The PILATUS modules are suitable for various X-ray applications such as diffraction and imaging techniques.

The setup and first results from commissioning of a fast online photon energy spectrometer for the vacuum ultraviolet free electron laser at Hamburg (FLASH) at DESY are presented. With the use of the latest advances in detector development, the presented spectrometer reaches readout frequencies up to 1 MHz. In this paper, we demonstrate the ability to record online photon energy spectra on a shot-to-shot base in the multi-bunch mode of FLASH. Clearly resolved shifts in the mean wavelength over the pulse train as well as shot-to-shot wavelength fluctuations arising from the statistical nature of the photon generating self-amplified spontaneous emission process have been observed. In addition to an online tool for beam calibration and photon diagnostics, the spectrometer enables the determination and selection of spectral data taken with a transparent experiment up front over the photon energy of every shot. This leads to higher spectral resolutions without the loss of efficiency or photon flux by using single-bunch mode or monochromators.

Hybrid pixel detectors are being developed for both photon science and high energy physics. The article will cover similarities and differences in pixel detectors for both applications using two of the pixel detectors developed at the Paul Scherrer Institute (Switzerland) as examples: the EIGER photon counting detector and the psi46dig chip, which has been developed for the Compact Muon Solenoid (CMS) tracking pixel detector upgrade. EIGER is a single photon counting hybrid pixel detector for applications at synchrotron light sources in the energy range from a few to 25 keV. It is characterized by a small pixel size (75 × 75 μm2), high count rate capability (106 counts/pixel/s) and very high data rate, which reaches 6 Gb/s for a 256 × 256 pixel chip. The CMS pixel detector is designed to provide charge information from the pixels in the harsh radiation environment at the Large Hadron Collider. The short time between bunches of 25 ns and the high event rate at luminosity up to 2 × 1034cm−2s−1 require a detector with high hit efficiency, with good timing resolution and the ability to retain timestamp information for the hits. The readout architecture is based on the transfer of hits from the pixels to the periphery, where the trigger validation is performed before data transfer. The data rates of the digitized output reach 160 Mb/s for a 52×80 pixel chip.The specific timing and rate requirements for the detectors, the analog performances (minimum threshold and noise), the power consumption and the radiation hardness will be compared. An overview on future developments based on mutual learning and common solutions will be discussed.

MONCH is a 25 μm pitch hybrid silicon pixel detector with a charge integrating analog read-out front-end in each pixel. The small pixel size brings new challenges in bump-bonding, power consumption and chip design. The MONCH02 prototype ASIC, manufactured in UMC 110 nm technology with a field of view of 4×4 mm2 and 160×160 pixels, has been characterized in the single photon regime, i.e. with less than one photon acquired per frame on average on a 3×3 pixel cluster. The low noise and small pixel size allow spatial interpolation with high resolution. Understanding charge sharing as a function of the photon absorption depth and sensor bias is a key for optimal processing of single photon data for high resolution imaging. To characterize the charge collection of the detector, the sensor was illuminated with a 20 keV photon beam in edge-on configuration at the SYRMEP beamline of Elettra. By slicing the beam by means of a 5 μm slit and scanning through the 320 μm silicon sensor depth, the charge collection is characterized as a function of the photon absorption depth for different sensor bias voltages.

EIGER is a single photon counting hybrid pixel detector being developed at Paul Scherrer Institute (PSI), Switzerland, for applications at synchrotron light sources in an energy range from a few to 25 keV. EIGER is characterized by a small pixel size (75 × 75 μm2), a frame rate up to 22 kHz and a small dead time between frames (4 μs). An EIGER module is a hybrid detector composed of a ≈ 8 × 4 cm2 monolithic silicon sensor bump bonded to 4 × 2 readout chips, for a total of 500 kpixels. Each pixel has a configurable depth (up to 12 bits) counter and records the number of photons impinging. Custom designed module electronics reads out the bits in the pixel counter and processes the data in the module before transferring them to a PC. A large dynamic range (32 bits) for the pixel counter can be obtained through on-board image summation. Rate corrections can be applied on-board to compensate for inefficiencies when the pixel counting rates approach pile-up levels around a million counts per second. The EIGER modules are the building blocks of large area detectors: a 1.5 and a 9 Mpixel systems are under development for the cSAXS beamline at the Swiss Light Source (SLS) at PSI. The very high frame rate capabilities are equally fast for multi-module systems due to the fully parallel data processing.The module calibration will be discussed, with emphasis on the choice of the optimal operation settings as a function of photon energy. The performance regarding threshold dispersion and minimum achievable threshold will be presented. In addition, the progress towards the production of larger multi-module systems will be discussed.

The SLS detector group develops silicon hybrid detectors for X-ray applications used in synchrotron facilities all over the world. Both microstrip and pixel detectors with either single photon counting or charge integrating read out are being developed. Low noise charge integrating detectors can be operated in single photon regime, i.e. with low fluxes and high frame rates in order to detect on average less than one photon per cluster of 2×2 pixels. In this case, the analog signal read out for each single X-ray provides information about the energy of the photon. Moreover the signal from neighboring channels can be correlated in order to overcome or even take advantage of charge sharing. The linear charge collection model describing microstrip detectors and large pixels is unsuitable for the calibration of small pitch pixel detectors due to the large amount of charge sharing occurring also in the corner region. For this reason, the linear charge collection model is extended to the case of small pixels and tested with monochromatic X-ray data acquired using the 25 μm pitch MONCH and the 75 μm pitch JUNGFRAU detectors. The successful outcome of the calibration of the MONCH detector is proven by the high energy resolution of the spectrum obtained by accumulating the counts from more than 6000 channels after the correction of the gain mismatches using the proposed model.

JUNGFRAU (adJUstiNg Gain detector FoR the Aramis User station) is a two-dimensional pixel detector for photon science applications at free electron lasers and synchrotron light sources. It is developed for the SwissFEL currently under construction at the Paul Scherrer Institute, Switzerland. Characteristics of this application-specific integrating circuit readout chip include single photon sensitivity and low noise over a dynamic range of over four orders of magnitude of photon input signal. These characteristics are achieved by a three-fold gain-switching preamplifier in each pixel, which automatically adjusts its gain to the amount of charge deposited on the pixel. The final JUNGFRAU chip comprises 256 × 256 pixels of 75 × 75 μm2 each. Arrays of 2 × 4 chips are bump-bonded to monolithic detector modules of about 4 × 8 cm2. Multi-module systems up to 16 Mpixels are planned for the end stations at SwissFEL. A readout rate in excess of 2 kHz is anticipated, which serves the readout requirements of SwissFEL and enables high count rate synchrotron experiments with a linear count rate capability of > 20 MHz/pixel. Promising characterization results from a 3.6 × 3.6 mm2 prototype (JUNGFRAU 0.2) with fluorescence X-ray, infrared laser and synchrotron irradiation are shown. The results include an electronic noise as low as 100 electrons root-mean-square, which enables single photon detection down to X-ray energies of about 2 keV. Noise below the Poisson fluctuation of the photon number and a linearity error of the pixel response of about 1% are demonstrated. First imaging experiments successfully show automatic gain switching. The edge spread function of the imaging system proves to be comparable in quality to single photon counting hybrid pixel detectors.

AGIPD is a charge integrating, hybrid pixel readout ASIC, which is under development for the European XFEL [1,2]. A dynamic gain switching logic at the output of the preamplifier (preamp) is used to provide single photon resolution as well as covering a dynamic range of at least 104·12.4 keV photons [3,4]. Moreover, at each point of the dynamic range the electronics noise should be lower than the Poisson fluctuations, which is especially challenging at the points of gain switching. This paper reports on the progress of the chip design on the way to the first full-scale chip AGIPD1.0, focusing on the optimization of the dynamic range and the implementation of protection circuits at the preamplifier input to avoid pixel destruction due to high intense spots.

MONCH, a charge integrating readout ASIC (Application Specific Integrated Circuit) prototype with a pixel pitch of 25 μm developed at PSI, allows new imaging applications in the field of micron resolution and spectral imaging. The small pixel size of this system facilitates charge sharing between pixels, which then can be exploited to gain additional information about the photon absorption position and photon energy. However, for reconstructing complete images from this information, sufficient hits need to be recorded and therefore acquisition times are potentially long. We present a fast read-out system, that is capable of acquiring enough statistics for an image in a few hours in combination with a position reconstruction algorithm, which has the potential to run in a similar amount of time on a fast computing node. We further present results of experiments with a comparable strip detector (small-pitch GOTTHARD system) showing that with the aid of single photon interpolation algorithms micron resolution is achievable. Additionally, we show that a similar position reconstruction algorithm works in the two dimensional case for MONCH.

Eiger is a single-photon counting x-ray pixel detector being developed at the Paul Scherrer Institut (PSI) for applications at synchrotron light sources. It follows the widely utilized and successful Pilatus detector. The main features of Eiger are a pixel size of 75 × 75 μm2, high frame rate capability of 22 kHz and negligible dead time between frames of 4 μs. This article contains a detailed description of Eiger detector systems, from the 500 kpixel single-module detector to large-area multi-modules systems. The calibration and performance of the first 500 kpixel system that is in routine user operation are also presented. Furthermore, a method of calibrating the energy of single-photon counting detectors along the detector gain axis is introduced. This approach has the advantage that the detector settings can be optimized at all energies for count rate capabilities. Rate capabilities of the system are reported for energies between 6 and 16 keV.

PSI is developing several new detector families based on charge integration and analog readout (CI) to respond to the needs of X-ray free electron lasers (XFELs), where a signal up to ~ 104 photons impinging simultaneously on a pixel make single photon counting detectors unusable. MONCH is a novel hybrid silicon pixel detector where CI is combined with a challengingly small pixel size of 25 × 25 μm2. CI enables the detector to process several incoming photon simultaneously in XFEL applications. Moreover, due to the small pixel size, the charge produced by an impinging photon is often shared. In low flux experiments the analog information provided by single photons can be used either to obtain spectral information or to improve the position resolution by interpolation. Possible applications are resonant and non-resonant inelastic X-ray scattering or X-ray tomography with X-ray tubes. Two prototype ASICs were designed in UMC 110 nm technology. MONCH01 contains only some test cells used to assess technology performance and make basic design choices. MONCH02 is a fully functional, small scale prototype of 4 × 4 mm2, containing an array of 160 × 160 pixels. This array is subdivided in five blocks, each featuring a different pixel architecture. Two blocks have statically selectable preamplifier gains and target synchrotron applications. In low gain mode they should provide single photon sensitivity (at 6-12 keV) as well as a reasonable dynamic range for such a small area ( > 120 photons). In high gain they target high resolution, low flux experiments where charge sharing can be exploited to reach μm resolution. Three other architectures address possible uses at XFELs and implement automatic switching between two gains to increase the dynamic range, as well as input overvoltage control. The paper presents the MONCH project and first results obtained with the MONCH02 prototype.

The SwissFEL, a free electron laser (FEL) based next generation X-ray source, is being built at PSI. An XFEL poses several challenges to the detector development: in particular the single photon counting readout, a successful scheme in case of synchrotron sources, can not be used. At the same time the data quality of photon counting systems, i.e. the low noise and the high dynamic range, is essential from an experimental point of view. Detectors with these features are under development for the EU-XFEL in Hamburg, with the PSI SLS Detector group being involved in one of these efforts (AGIPD). The pulse train time structure of the EU-XFEL machine forces the need of in pixel image storage, resulting in pixel pitches in the 200 μm range. Since the SwissFEL is a 100 Hz repetition rate machine, this constrain is relaxed. For this reason, PSI is developing a 75 μm pitch pixel detector that, thanks to its automatic gain switching technique, will achieve single photon resolution and a high dynamic range. The detector is modular, with each module consisting of a 4 × 8 cm2 active sensor bump bonded to 8 readout ASICs (Application Specific Integrated Circuit), connected to a single printed circuit readout board with 10GbE link capabilities for data download. We have designed and tested a 48 × 48 pixel prototype produced in UMC110 nm technology. In this paper we present the general detector and ASIC design as well as the results of the prototype characterization measurements.

EIGER is the next generation of single photon counting pixel detector for synchrotron radiation designed by the PSI-SLS detector group. It features a pixel size of 75 × 75μm2 and frame rates up to 23 kHz. The chip contains 256 × 256 pixels, has a total size of 19.3 × 20 mm2 and provides 4, 8 and 12 bit counting modes. This dynamic range is extendable to 32 bits with continuous read/write and summation of frames on the fly in firmware. Along with X-ray absorption images, the characterization and performance of the chip is presented. The energy calibration, noise, minimum energy threshold and rate capability measured with a single chip test system in a X-ray tube and at the SLS-PSI synchrotron are shown. Trimming studies and irradiation effects are discussed as well. To conclude, the status of the production of larger detector systems consisting of 2 × 4 chip modules and multi modules detector systems (9 Mpixels; 3 × 6 modules) is outlined.

A charge integrating readout ASIC (Application Specific Integrated Circuit) for silicon strip sensors has been developed at PSI in collaboration with DESY. The goal of the project is to provide a charge integrating readout system able to cope with the pulsed beam of XFEL machines and at the same time to retain the high dynamic range and single photon resolution performances typical for photon counting systems. The ASIC, designed in IBM 130 nm CMOS technology, takes advantage of its three gain stages with automatic stage selection to achieve a dynamic range of 10000 12 keV photons and a noise better than 300 e.n.c.. The 4 analog outputs of the ASIC are optimized for speed, allowing frame rates higher than 1 MHz, without compromises on linearity and noise performances. This work presents the design features of the ASIC, and reports the characterization results of the chip itself.

We present a front-end readout ASIC developed for a new family of ultra-fast 1D imaging detectors operating at frame rates of up to 12 MHz. The ASIC, realized in 110 nm CMOS technology, is designed to be compatible with different semiconductor sensors. The final chip will contain up to 128 channels, each consisting of a Charge-Sensitive Amplifier, a noise shaper based on a fully-differential Correlated Double Sampling stage and a Sample-and-Hold buffer. The differential channels are connected through 8:1 analog multiplexers to the output drivers, which directly interface external analog-to-digital converters. A first prototype with a limited number of channels have been characterized with a Si microstrip detector. When operated at the maximum frame-rate of 12 MHz, the ASIC exhibits an Equivalent Noise Charge of 417 electrons with a detector capacitance of 1.3 pF.