Evaluation of front-end readout system with APV25 for Si-PAD and Tungsten based electromagnetic calorimeter FoCal at LHC ALICE

In the LHC-ALICE, there is an upgrade plan to construct a Forward Calorimeter(FoCal) intended for the measurement of direct photons at forward rapidity (3.5<𝜂<5.3). The FoCal-detector installation during the long shutdown 3 in 2024 is under discussion. FoCal consists of an electromagnetic calorimeter(FoCal-E) and a hadron calorimeter(FoCal-H). FoCal-E is a sampling-type calorimeter using tungsten as the particle absorption layer and silicon as the detection layer. FoCal-E consists of low granularity layer(LGL) for the mearsurement of the energy of photons and high granularity layer(HGL) for the identification of 𝜋0/𝛾. From 2014 on ward , the Tsukuba group is in charge of evaluating the performance of LGL. We have conducted tests of this system on three occasions by using the CERN PS and SPS beam lines.

Based on past results, in 2017, we performed the test-beam experiment for one of the prototype silicon sensors with Tungsten layer at ELPH in Tohoku University in Japan, by using positron beams of 800MeV/c. In this test, we measured the response of the silicon pad and readout electronics with APV25 hybrid for minimum ionizing particles and electromagnetic showers.

In this presentation, the results of the new readout system from the test-beam experiment at ELPH will be shown.