SparkPix-T: Spatial and Time Resolving Front-End ASIC with MHz-Rate Information Extraction for Momentum Spectroscopy at LCLS-II

• Main Authors: Markovic, B., Bakalis, C., Blaj, G., Defay, X., Doering, D., Gupta, A., Hasi, J., Kenney, C., King, P., Pena-Perez, A., Reese, B., Rota, L., Ruckman, L., Segal, J., Driver, T., Cryan, J., Hansson, C., Dragone, A.
• Format: Conference Proceeding
• Language: English
• Subjects: Atmospheric measurements; Information retrieval; Particle measurements; Preamplifiers; Semiconductor detectors; Semiconductor device measurement; Spectroscopy
• ISSN: 2577-0829
• DOI: 10.1109/NSSMICRTSD49126.2023.10338624

SparkPix-T is a spatial and time resolving front-end ASIC capable of operation at up to 1 MHz repetition rate, developed to enable massive multi-particle coincidence experiments at the TMO instrument at LCLS-II. It has 100 μm x 100 μm pixels arranged in a 176 x 192 matrix configuration, capable of measuring charged particle time-of-arrival (TOA) with 100 ps resolution and 6.5 μs range. Signal energy is indirectly assessed through 8-bit time-over-threshold (TOT) measurements. A fast gating of the front-end preamplifier is implemented for rejection of photons produced by the LCLS pulse that could otherwise blind the detector to upcoming signal. A sparse readout information extraction scheme is implemented to allow for a trade-off between repetition rate and event occupancy (percentage of pixels with signal above threshold per repetition cycle). At 1 MHz rate the ASIC can sustain occupancy of 0.5% without data loss, at 100 kHz the occupancy can be 5%, while a full matrix readout (100% occupancy) is possible at 5 kHz. SparkPix-T has been fabricated in a 0.13 μm CMOS technology and its design and initial characterization will be reported.