The Square Kilometre Array (SKA)

Abstract:

We describe near-field tests and results of an 8 pixel close-packed feedhorn array that will be a key component of an 8 pixel prototype 350 GHz SIS mixer array receiver prototype under construction at SAO. We have fabricated an array of smooth walled multiple flare angle feedhorns by direct drilling into a single block of aluminum. Testing of the feedhorns was carried out using a nearfield scanner and a vector network analyzer based on custom built transmitters and receivers and an HP vector voltmeter. The vector nearfield data is transformed to the farfield radiation pattern using Python code based on the NF2FF Matlab script[1].

Abstract:

The small size telescopes (SSTs), spread over an area of several square km, dominate the CTA sensitivity in the photon energy range from a few TeV to over 100 TeV, enabling for the detailed exploration of the very high energy gamma-ray sky. The proposed telescopes are innovative designs providing a wide field of view. Two of them, the ASTRI (Astrophysics con Specchi a Tecnologia Replicante Italiana) and the GCT (Gamma-ray Cherenkov Telescope) telescopes, are based on dual mirror Schwarzschild-Couder optics, with primary mirror diameters of 4 m. The third, SST-1M, is a Davies-Cotton design with a 4 m diameter mirror. Progress with the construction and testing of prototypes of these telescopes is presented. The SST cameras use silicon photomultipliers, with preamplifier and readout/trigger electronics designed to optimize the performance of these sensors for (atmospheric) Cherenkov light. The status of the camera developments is discussed. The SST sub-array will consist of about 70 telescopes at the CTA southern site. Current plans for the implementation of the array are presented.