Tests of FARICH prototype with precise photon position detection

In June 2012 a FARICH prototype from Philips Digital Photon Counting (PDPC) based on a photon camera with dimensions of 200×200 mm has been tested at CERN. Remarkable particle separation has been achieved with a 4-layer aerogel sample: the π/K separation at a 6 GeV/c momentum is 3.5σ, the μ/π separation is 5.3σ at 1 GeV/c. The analysis of the data has shown that the main contribution to the accuracy of the ring radius measurement comes from aerogel. The development of focusing aerogels is proceeding in two main directions: tuning of production technology of multilayer blocks and development of a new production method with continuous density (refractive index) gradient along the block depth. The beam test was carried out in December 2012-January 2013 at the electron beam test facility at the VEPP-4 M e+e− collider. The goal of this test was to measure different single layer and focusing aerogel samples, both multilayer and gradient. Aerogel samples were tested with a PDPC FARICH prototype. A part of DPC SPADs in each pixel was disabled to form an active area of 1×1 mm2. The collected data proved that gradient aerogel samples focus Cherenkov light.