Pawel Rajda

The Cherenkov Telescope Array (CTA) will explore with unprecedented precision the Universe in the gammaray domain covering an energy range from 50 GeV to more the 300 TeV. To cover such a broad range with a sensitivity which will be ten time better than actual instruments, different types of telescopes are needed: the Large Size Telescopes (LSTs), with a ∼24 m diameter mirror, a Medium Size Telescopes (MSTs), with a ∼12 m mirror and the small size telescopes (SSTs), with a ∼4 m diameter mirror. The single mirror small size telescope (SST-1M), one of the proposed solutions to become part of the small-size telescopes of CTA, will be equipped with an innovative camera. The SST-1M has a Davies-Cotton optical design with a mirror dish of 4 m diameter and focal ratio 1.4 focussing the Cherenkov light produced in atmospheric showers onto a 90 cm wide hexagonal camera providing a FoV of 9 degrees. The camera is an innovative design based on silicon photomultipliers (SiPM ) and adopting a fully digital trigger and readout architecture. The camera features 1296 custom designed large area hexagonal SiPM coupled to hollow optical concentrators to achieve a pixel size of almost 2.4 cm. The SiPM is a custom design developed with Hamamatsu and with its active area of almost 1 cm² is one of the largest monolithic SiPM existing. Also the optical concentrators are innovative being light funnels made of a polycarbonate substrate coated with a custom designed UV-enhancing coating. The analog signals coming from the SiPM are fed into the fully digital readout electronics, where digital data are processed by high-speed FPGAs both for trigger and readout. The trigger logic, implemented into an Virtex 7 FPGA, uses the digital data to elaborate a trigger decision by matching data against predefined patterns. This approach is extremely flexible and allows improvements and continued evolutions of the system. The prototype camera is being tested in laboratory prior to its installation expected in fall 2017 on the telescope prototype in Krakow (Poland). In this contribution, we will describe the design of the camera and show the performance measured in laboratory.

The Cherenkov Telescope Array (CTA) will be the future observatory for ground-based TeV gamma-ray astronomy. At two sites, one in the northern and one in the southern hemisphere, CTA will feature about one hundred telescopes of different size classes in order to significantly improve the sensitivity and energy range with respect to current Cherenkov facilities. FlashCam is a camera system proposed for the medium-sized telescopes of CTA that implements a fully-digital readout and trigger processing, which allows the reconfiguration of the trigger algorithm and the signal shaping. For the mass production of a substantial number of FlashCam cameras, efficient and reliable testing routines have been developed. In this contribution, the concept and the procedures for large-scale testing of the readout electronics are outlined. Additionally, a fast multi-channel pulse generator specifically designed for the functional testing of FlashCam FADC modules setup is presented.