Poster Summary: The SST-1M Telescope Proposed for the Cherenkov Telescope Array and its Calibration Strategy
(by Cyril Alispach) There is a strong liaison between neutrino and gamma-ray astronomy, which have in common the sources, as well sources of cosmic rays in hadronic acceleration scenarios. Gamma-rays are detected with high statistics and can help identify the sources of which IceCube is seeing a diffuse flux.
The Cherenkov Telescope Array will comprise a sub-array of up to 70 small sized telescopes (SSTs) in the southern array. The SST-1M project, a 4 m-diameter Davies-Cotton telescope with 9 degrees FoV and a 1296 pixels SiPM camera (see figure 1), is designed to meet the requirements of the next generation ground based gamma-ray observatory in the energy range above 3 TeV.
The first camera prototype of the SST-1M project is undergoing calibration tests at the University of Geneva. Calibration is performed using a dedicated LED board mounted on front of the camera. The camera test setup is composed of pulsed and continuous LEDs allowing to emulate signal and background events. It is used to study the charge resolution for various NSBs. Gain, baseline, electronic noise, optical crosstalk and SiPM gain smearing are extracted using novels PDFs of SiPM response in good agreement with data.
In Fig. 2 one can see the multiple photo-electron spectrum of one of the camera pixel with its best fit. The model used for the fit is a Poisson distribution distorted by optical crosstalk. The optical crosstalk model allows to extract all calibration parameters as well as to calibrate the LEDs through the determination of the mean detected number of photo-electron. Later on, calibrated LEDs together with Monte-Carlo simulations will allow to compare the camera response to a gamma-ray event (see figure 3, a 20 TeV gamma-ray MC event).