Photon detection is a key factor to study many physical processes in several areas of fundamental physics research as well as industrial application (i.e. medical equipment, environmental measurement equipment, quantum computing and oil well logging). Focusing the attention on photodetectors for particle astrophysics, we understand that we are very close to new discoveries and new results. In order to push the progress in the study of very high-energy or extremely rare phenomena (e.g. dark matter, proton decay, neutrinos from astrophysical sources) the current and future experiments require additional improvements in linearity, gain, quantum efficiency and single photon counting capability. To meet the requirements of these classes of experiments, we propose a new design for a modern hybrid photodetector: the VSiPMT (Vacuum Silicon PhotoMultiplier Tube). The idea is to replace the classical dynode chain of a PMT with a SiPM, which therefore acts as a single stage Geiger electron detector and amplifier, without statistical fluctuations. The aim is to match the large sensitive area of a photocathode with the performances of the SiPM technology. The previous VSiPMT prototypes already showed many attractive features such as low power consumption, very large dynamic range, excellent photon counting capability and low voltage driven gain. We now present the results of the full characterization of the latest and largest version achieved up to now, a 2-inches VSiPMT manufactured by Hamamatsu.
With the observation of the gravitational wave event of August 17th 2017 and then with those of the extragalactic neutrino of September 22nd, the multi messenger astronomy era has definitely begun. With the opening of this new panorama, it is necessary to have a perfect coordination of the several observatories. Crystal Eye is an experiment aimed at the exploration of the electromagnetic counterpart of the gravitational wave events, that represent the missing observational link between short Υ-ray bursts and gravitational waves from neutron star mergers. The experiment we propose is a wide field of view observatory. The Crystal Eye objectives will be: to alert the community about events containing soft X-ray and low energy Υ-ray, to monitor long-term variabilities of X-ray sources, to stimulate multi-wavelength observations of variable objects, and to observe diffuse cosmic soft X-ray emissions.