The SparkPix-S ASIC for the sparsified readout of 1 MHz frame-rate X-ray cameras at LCLS-II: pixel design and simulation results

Journal Article · 14 January 2024 · Journal of Instrumentation

DOI: https://doi.org/10.1088/1748-0221/19/01/c01010 · OSTI ID:2403407

Rota, L. ^[1]; Mele, Fillippo ^[2]; Habib, A. ^[3]; Kim, H. ^[3]; King, P. ^[3]; Markovic, B. ^[3]; Perez, A. Peña ^[3]; Dragone, A. ^[3]

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1. SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States); SLAC
2. Politecnico di Milano, Como (Italy); Istituto Nazionale di Fisica Nucleare (INFN), Milano (Italy)
3. SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)

Exploiting the “sparse” nature of the information in XPCS (X-ray Photon Correlation Spectroscopy) and XSVS (Speckle Visibility Spectroscopy) experiments, we present the SparkPix-S, a 3-sides buttable Application Specific Integrated Circuit (ASIC) based on a sparsified readout strategy for large-format hybrid detectors. The SparkPix-S architecture, based on the successful ePix family, will be composed as follows: a front-end 2-D matrix of 384×352 square pixels with 50 µm pitch is arranged to match the dimensions of a PIN Si-sensor matrix; charge readout, signal shaping and amplitude discrimination is performed at pixel-level, by means of a low-power (<18 µW) analog processor, which, in case of an event, negotiates access to an analog bus placed every other column; on the chip periphery (balcony), the information on each bus is digitized by an array of successive approximation analog-to-digital converters (SAR-ADCs) running at 10 Msps; on the digital back-end the global logic will generate the output data stream using low-voltage differential signalling (LVDS). A first prototype of the SparkPix-S, with a reduced matrix size of 96×96 pixels, is currently under production on a 130 nm CMOS technology. Simulated performance results show an equivalent noise charge <60 el. r.m.s. at 1 MHz repetition rate, with a maximum input energy of 60 keV and capability to discriminate charge signals with equivalent energy as low as 900 eV.

• Research Organization: SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• Grant/Contract Number: AC02-76SF00515
• OSTI ID: 2403407
• Journal Information: Journal of Instrumentation, Journal Name: Journal of Instrumentation Journal Issue: 01 Vol. 19; ISSN 1748-0221
• Publisher: Institute of Physics (IOP)Copyright Statement
• Country of Publication: United States
• Language: English