The CirPAD, a circular 1.4†M hybrid pixel detector dedicated to X-ray diffraction measurements at Synchrotron SOLEIL.

One of the challenges of all synchrotron facilities is to offer the highest performance detectors for all their specific experiments, in particular for X-ray diffraction imaging and its high throughput data collection. In that context, the DiffAbs beamline, the Detectors and the Design and Engineering groups at Synchrotron SOLEIL, in collaboration with ImXPAD and Cegitek companies, have developed an original and unique detector with a circular shape. This detector is based on the hybrid pixel photon-counting technology and consists of the specific assembly of 20 hybrid pixel array detector (XPAD) modules. This article aims to demonstrate the main characteristics of the CirPAD (for Circular Pixel Array Detector) and its performance - i.e. excellent pixel quality, flat-field correction, high-count-rate performance, etc. Additionally, the powder X-ray diffraction pattern of an LaB6 reference sample is presented and refined. The obtained results demonstrate the high quality of the data recorded from the CirPAD, which allows the proposal of its use to all scientific communities interested in performing experiments at the DiffAbs beamline.

Backside-illuminated scientific CMOS detector for soft X-ray resonant scattering and ptychography.

The impressive progress in the performance of synchrotron radiation sources is nowadays driven by the so-called `ultimate storage ring' projects which promise an unprecedented improvement in brightness. Progress on the detector side has not always been at the same pace, especially as far as soft X-ray 2D detectors are concerned. While the most commonly used detectors are still based on microchannel plates or CCD technology, recent developments of CMOS (complementary metal oxide semiconductor)-type detectors will play an ever more important role as 2D detectors in the soft X-ray range. This paper describes the capabilities and performance of a camera equipped with a newly commercialized backside-illuminated scientific CMOS (sCMOS-BSI) sensor, integrated in a vacuum environment, for soft X-ray experiments at synchrotron sources. The 4 Mpixel sensor reaches a frame rate of up to 48 frames s-1 while matching the requirements for X-ray experiments in terms of high-intensity linearity (>98%), good spatial homogeneity (<1%), high charge capacity (up to 80 ke-), and low readout noise (down to 2 e- r.m.s.) and dark current (3 e- per second per pixel). Performance evaluations in the soft X-ray range have been carried out at the METROLOGIE beamline of the SOLEIL synchrotron. The quantum efficiency, spatial resolution (24 line-pairs mm-1), energy resolution (<100 eV) and radiation damage versus the X-ray dose (<600 Gy) have been measured in the energy range from 40 to 2000 eV. In order to illustrate the capabilities of this new sCMOS-BSI sensor, several experiments have been performed at the SEXTANTS and HERMES soft X-ray beamlines of the SOLEIL synchrotron: acquisition of a coherent diffraction pattern from a pinhole at 186 eV, a scattering experiment from a nanostructured Co/Cu multilayer at 767 eV and ptychographic imaging in transmission at 706 eV.

First pump-probe-probe hard X-ray diffraction experiments with a 2D hybrid pixel detector developed at the SOLEIL synchrotron.

A new photon-counting camera based on hybrid pixel technology has been developed at the SOLEIL synchrotron, making it possible to implement pump-probe-probe hard X-ray diffraction experiments for the first time. This application relies on two specific advantages of the UFXC32k readout chip, namely its high frame rate (50 kHz) and its high linear count rate (2.6 × 106 photons s-1 pixel-1). The project involved the conception and realization of the chips and detector carrier board, the data acquisition system, the server with its specific software, as well as the mechanical and cooling systems. This article reports on in-laboratory validation tests of the new detector, as well as on tests performed at the CRISTAL beamline within the targeted experimental conditions. A benchmark experiment was successfully performed, showing the advantages of the pump-probe-probe scheme in correcting for drifts of the experimental conditions.