The Cherenkov Telescope Array (CTA) project aims to implement the world’s largest next generation of Very High Energy gamma-ray Imaging Atmospheric Cherenkov Telescopes devoted to the observation from a few tens of GeV to more than 100 TeV. To view the whole sky, two CTA sites are foreseen, one for each hemisphere. The sensitivity at the lowest energy range will be dominated by four Large Size Telescopes, LSTs, located at the center of each array and designed to achieve observations of high red-shift objects with the threshold energy of 20 GeV. The LST is optimized also for transient low energy sources, such as Gamma Ray Bursts (GRB), which require fast repositioning of the telescope. The overall design and the development status of the first LST telescope will be discussed.
We developed the gamma-ray camera for SUBARU infrared-optical telescope, named CheSS (Cherenkov light detecting System on Subaru). The CheSS was designed based on Imaging Atmospheric Cherenkov Technique (IACT) which has been established by detections of high energy gamma-ray sources in the last decade. According to our Monte Carlo simulation, the energy thresholds of the CheSS for the Crab are 30 GeV at zenith angle of 10 degrees, and the expected sensitivity for the unpulsed component can reach ~10σ level and more for pulsed one during 10 hours on-source pointing.