1. The VSiPMT: A new Generation of Photons Detectors G. Barbarino 1,2, F. C. T. Barbato 1,2, R. de Asmundis 2, G. De Rosa 1,2, F. Di Capua 1, P. Migliozzi 2, C. M. Mollo 2, D. Vivolo 1,2 1 Department of Physics, University of Naples “Federico II”, Naples, Italy - 2 INFN, Naples, Italy Peak values histogram MEASUREMENT CONDITIONS: VSiPMT illuminated by a pulsed laser light at low intensity (407nm) Oscilloscope triggered in synch with the laser Responses for multiple triggers are overlaid MEASUREMENT CONDITIONS: VSiPMT illuminated by a pulsed laser light at low intensity (407nm) Oscilloscope triggered in synch with the laser Responses for multiple triggers are overlaid HV needed only for electron transfer NO POWER CONSUMPTION (NULL current) Gain indipendent from HV EASY STABILIZATION Reaching the plateau region at even lower voltages will be possible by reducing the SiO 2 coating layer CHARACTERISTICS: 7mm x 7mm entrance window 3 mm Ø GaAsP photocathode 1mm 2 MPPC XY Scan Homogeneous efficiency ≈ 0.2 over a 7mm 2 surface Surface increase factor ≈ 7 High gain (10 5 ÷10 6 ) LINEAR TREND Laser Trigger VSiPMT spe signal ΔT distribution ΔT VSiPMT TTS(σ) < 0.5 ns VSiPMT The output from the VSiPMT is fed as the stop signal via a discriminator; We measure the time interval between the "start" and "stop" signals. Per each light level (number of photons), every 20 minutes we measured the average number of detected photons The detector shows NO FATIGUE EFFECT ON HIGH ILLUMINATION Photocathode Focusing Ring Focusing Grid SiPM NO DIVIDER  no power dissipation or complicated circuit Single-state amplifiers based on an OP-AMP in non inverting configuration. 3 different gain MPPC We measured the dark counts rate of the VSiPMT. We found this rate to be equal to the dark count rate of the MPPC. The realization of the VSiPMT (Vacuum Silicon Photo Multiplier Tube) will trigger a revolution in the photodetectors field for near- future applications. Emerging fields like particle astrophysics or medical equipment, physical check-ups and diagnosis, biomedicine will require further improvements in photodetectors performances, as linearity, gain, quantum efficiency and single photon counting capability. The first VSiPMT prototype shows excellent performances: UNRIVALLED photon counting capability; Stable gain (NOT depending on HV); Very fast response (TTS < 0.5 ns ). This results lead us to believe that the proposed device has the potential to fulfil the requirements of the next generation of experiments. Our current planning for this project is the realization and characterization of VSiPMT prototypes with bigger (1” – 3”) photocathodes. The device will be realized in two different configurations: the first with a classical glass envelope and a 1mm 2 MPPC to be tested at room temperature, the second with a special envelope and photocathode with a 9mm 2 MPPC to be tested at cryogenic temperatures. These devices could cover all the requirements for next 10 years of big physics experiments and in particular astro-particle physics experiments (e.g. dark matter, Air Cherenkov, km3 in Mediterranean sea). VSiPMT (Vacuum Silicon PhotoMultiplier Tube) is an innovative design we propose for a revolutionary hybrid photon detector. The idea is to replace the classical dynode chain of a PMT with a SiPM, which therefore acts as an electron detector and amplifier. The aim is to match the large sensitive area of a photocathode with the performances of the SiPM technology. The VSiPMT will have many attractive features such as low power consumption, weak sensitivity to magnetic fields, excellent photon counting capability and so on. We first studied the feasibility of this detector both from theoretical and experimental points of view, by implementing a Geant4-based simulation and studying the response of a special non-windowed MPPC by Hamamatsu with an electron beam. Thanks to this result Hamamatsu realized two VSiPMT industrial prototypes. We present the results of a full characterization of the VSiPMT prototype.