Speaker
Description
The Mu2e calorimeter is composed by two disks of 1348 un-doped parallelepiped CsI crystals of $34\times 34\times 200$ mm$^3$
dimension, each one readout by two large area SiPM arrays. We translated the calorimeter requirements in a series of technical specifications for the SiPMs that are summarized by the following list:
(1) a high gain, above 10^6, for each monolithic (6× 6) mm$^2$ SiPM cell;
(2) a good photon detection efficiency, PDE, of above 20\% at 310 nm to match the light from un-
doped CsI crystals;
(3) a large active area that, in combination with the PDE, could provide a light yield of above 20 p.e./MeV;
(4) a fast rise time and a narrow signal width to improve time resolution and pileup rejection;
(5) a Mean to Time Failure (MTTF) of O(10$^6$) hours;
(6) and a good resilience to neutrons for a total fluency up to 10$^12$ n(1 MeVeq)/cm$^2$.
A modular and custom SiPM layout has been chosen to satisfy these requirements. The configuration readout of 2 series of three
$6\times$6 mm$^2$ monolithic SiPMs has been selected to overcome the issues related to the parallel connection that, due to the large capacitance, could spoil the pileup rejection and the energy and time measurements.
After pre-production we have selected Hamamatsu as vendor and the production of 4000 pieces is ongoing.
A detailed quality assurance, QA, will be carried out on each SiPM, with an automatized station built by INFN Pisa, for the determination of the operation voltage, gain, quenching time and dark current. For small samples of each production batch, the measurement of the MTTF and the increase of the dark current increase as a function of the neutron fluency will be carried out.
Secondary topics
photosensors
| Applications | Design concepts for future calorimeter at the intensity frontier |
|---|---|
| Primary topic | Silicon |
