2019/07/22 by Jason Watson, Watson, Jason John, J. Zorn +1
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #FOS: Physical sciences #Instrumentation and Methods for Astrophysics (astro-ph.IM) #Particle Detector Development and Performance #Radiation Detection and Scintillator Technologies
paper · pdf · doi:10.48550/arxiv.1907.09252
openalex publication_date 2019/07/22 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The Cherenkov Telescope Array (CTA) will present the next leap forward in\ngamma-ray astronomy, pushing beyond the present energy frontier to probe beyond\n300 TeV. This capability is provided by the 70 Small Sized Telescopes (SSTs).\nThe SSTs are spread across the four square kilometres of the array to detect\nthe rare, but bright, Cherenkov showers produced by the highest-energy gamma\nrays. One proposed camera design for the SSTs is the Compact High Energy Camera\n(CHEC). Its compact and curved focal plane design is tailored for dual-mirror\nSchwarzschild-Couder telescopes, making it compatible with two of the three\ntelescope proposals for the SSTs. The latest design of CHEC (known as CHEC-S)\nutilises silicon photomultipliers (SiPMs); an attractive alternative to\ntraditional photomultiplier tubes, offering improved photon detection\nefficiency and photoelectron counting resolution for a large dynamic range,\nacross tightly-packed pixels. However, SiPMs suffer from the phenomena of\noptical crosstalk, which degrades the ability to resolve the number of photons\nincident on the photosensor. CHEC-S also features full-waveform readout at\nnanosecond sampling resolution with a flexible trigger scheme. This is\nfacilitated by the TARGET (TeV Array Read-out with GSa/s sampling and Event\nTrigger) modules attached to the SiPMs. This contribution describes the concept\nand technical design of CHEC-S and displays the key performance results,\nmatched against the criteria required for a CTA camera. The limitation caused\nby the optical crosstalk of the SiPM is highlighted, and the expected\nperformance with more recent iterations of the photosensor technology is also\ndemonstrated.\n