Speaker
Mrs
Raffaella Donghia
(LNF - INFN)
Description
The Mu2e calorimeter is composed by two disks of 1348 un-doped
parallelepiped CsI crystals of 34x34x200 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:
- high gain, above 10^6, for each monolithic (6x6) mm^2 SiPM cell;
- good photon detection efficiency, PDE, of above 20% at 310 nm to well match the light emitted by the un-doped CsI crystals;
- large active area that, in combination with the PDE, could provide a light yield of above 20 p.e./MeV;
- fast rise time and a narrow signal width to improve time resolution and pileup rejection;
- Mean to Time Failure (MTTF) of O(10$^6$) hours;
- good resilience to neutrons for a total fluency up to 10^12 n(1 MeV-eq)/cm^2.
A modular and custom SiPM layout has been chosen to satisfy these
requirements. A pre-production of 150 Mu2e SiPMs has been procured by
three international firms (Hamamatsu, Sensl and Advansid). A detailed
quality assurance, QA, has been carried out on each SiPM. A summary of
the techniques used and of the QA characterization of the sensors will
be shown.
Primary author
Bertrand Echenard
(Caltech)