Silicon Photomultipliers for the decay tunnel instrumentation of the ENUBET neutrino beam
Abstract
The goal of the ENUBET project is to demonstrate that a precision of ∼1% on measurement of the absolute neutrino cross section at GeV scale can be achieved by monitoring the positron production in the decay tunnel coming from the three-body semileptonic decays of kaons. The baseline option for the tunnel instrumentation employs a fine-grained shashlik calorimeter with a 4.3 X 0 longitudinal segmentation to separate positrons and pions coming from other decay modes of kaons. The system is complemented by rings of plastic scintillator doublets below the calorimeter acting as a photon veto to suppress the π 0 background and to provide timing informations. SiPMs instrumenting the detector will be exposed to sizeble amounts of neutrons arising in hadronic showers. In order to reproduce such a working environment, SiPMs with different cell size (from 12 to 20 μm ) were irradiated at the INFN-LNL CN Van Der Graaf with neutron fluences up to 2×10 11 n/cm 2 (1 MeV-eq.). The exposed light sensors were characterized in terms of I–V curves at different irradiation levels, and their response tested by exposing a prototype on beam at CERN. In this contribution we will report the results of the described tests on SiPMs, together with the advances in their integration with the ENUBET detectors.