CSPAD-140k: A versatile detector for LCLS experiments

Abstract

14With the successful operation of three 2.3 megapixel, 120Hz readout rate, hybrid pixel array detectors 15 at the Linac Coherent Light Source (LCLS), the SLAC National Accelerator Laboratory detector group is 16 now exploring additional applications based on the same detector platform. These megapixel cameras 17 are based on the Cornell-SLAC hybrid Pixel Array Detector (CSPAD). 18The CSPAD platform is developed around the CSPAD ASIC, a 36 kilopixel device, each pixel at 19 110x110μm 2 . Important characteristics of the CSPAD (room temperature operation, 14bit on chip 20 digitization with a purely digital data interface, and scaling modularity) make it an effective choice for 21 designing detector variants that are optimized for a range of experiments and applications. 22One of the first spin-off detectors based on this proven CSPAD platform is the CSPAD-140k: a 140 23 kilopixel detector, with an active area of approximately 4x4cm 2 and four ASICs, bundled in a small, 24 inexpensive and easy-to-deploy package. Due to its versatility it has already been used successfully in 25 several experiments at the CXI, XPP and XCS instruments at LCLS. The work also describes problems 26 faced by scaling from a prototype system to a full size x-ray camera and presents the current status on 27 the improvements achieved. 28 29

Nonsequential two-photon absorption from the K shell in solid zirconium

“…A Cornell-SLAC hybrid pixel array detector (CSPAD) 140-K pixel array detector with 110 × 110 μm 2 pixels [18] was positioned at 33 cm from the target such that each pixel subtends = 1.1 × 10 −7 srad, corresponding to a total solid angle of ∼15 × 10 −3 srad. To further suppress the background due to scattering, a Zr filter was inserted in front of the CSPAD.…”

“…The data are binned according to x-ray photon energy converted from the charge collected assuming a single photon is absorbed in a pixel. Individual detector frames were corrected for gain nonuniformity and a common-mode offset [18]. By far the dominant peak (0) corresponds to pixels in which no photons were absorbed, and the width corresponds to the electronic noise under dark conditions.…”

The Coherent X-ray Imaging instrument at the Linac Coherent Light Source

“…Both chambers are also designed for laser in-coupling to facilitate pump-probe experiments. Small versions of the CSPAD, consisting of only 1/16 of the full CSPAD (Herrmann et al, 2013) are available to be used for a variety of experiments and may be mounted in multiple locations along the instrument (Szlachetko et al, 2014) and inside the sample chambers (Kern et al, 2013). Sample delivery is critical for FEL experiments owing to the type of samples and the high repetition rate of the machine.…”

ePix100 camera: Use and applications at LCLS

“…Analog integrating imaging detectors, with readout speed matching the 120 Hz repetition rate of the source, have been of limited availability [2,3]. The first detector specifically developed for and deployed at LCLS is the Cornell-SLAC Pixel Array Detector (CSPAD) [4][5][6][7][8]. This hybrid pixel array detector, developed in several form factors, has been used for a broad range of applications.…”