  The Mu2e calorimeter is composed of two disks each containing 1348 pure CsI
crystals, each crystal read out by two arrays of 6x6 mm2 monolithic SiPMs. The
experimental requirements have been translated in a series of technical
specifications for both crystals and SiPMs. Quality assurance tests, on first
crystal and then SiPM production batches, confirm the performances of
preproduction samples previously assembled in a calorimeter prototype and
tested with an electron beam. The production yield is sufficient to allow the
construction of a calorimeter of the required quality in the expected times.
