TY - JOUR T1 - The calorimeter of the Mu2e experiment at Fermilab JF - Journal of Instrumentation Y1 - 2017 A1 - N. Atanov A1 - V. Baranov A1 - J. Budagov A1 - F. Cervelli A1 - F. Colao A1 - M. Cordelli A1 - G. Corradi A1 - E. Dané A1 - Y.I. Davydov A1 - S. Di Falco A1 - E. Diociaiuti A1 - S. Donati A1 - R. Donghia A1 - B. Echenard A1 - K. Flood A1 - S. Giovannella A1 - V. Glagolev A1 - F. Grancagnolo A1 - F. Happacher A1 - D.G. Hitlin A1 - M. Martini A1 - S. Miscetti A1 - T. Miyashita A1 - L. Morescalchi A1 - P. Murat A1 - G. Pezzullo A1 - F. Porter A1 - F. Raffaelli A1 - Tommaso Radicioni A1 - M. Ricci A1 - A. Saputi A1 - I. Sarra A1 - F. Spinella A1 - G. Tassielli A1 - V. Tereshchenko A1 - Z. Usubov A1 - R.Y. Zhu AB - The Mu2e experiment at Fermilab looks for Charged Lepton Flavor Violation (CLFV) improving by 4 orders of magnitude the current experimental sensitivity for the muon to electron conversion in a muonic atom. A positive signal could not be explained in the framework of the current Standard Model of particle interactions and therefore would be a clear indication of new physics. In 3 years of data taking, Mu2e is expected to observe less than one background event mimicking the electron coming from muon conversion. Achieving such a level of background suppression requires a deep knowledge of the experimental apparatus: a straw tube tracker, measuring the electron momentum and time, a cosmic ray veto system rejecting most of cosmic ray background and a pure CsI crystal calorimeter, that will measure time of flight, energy and impact position of the converted electron. The calorimeter has to operate in a harsh radiation environment, in a 10−4 Torr vacuum and inside a 1 T magnetic field. The results of the first qualification tests of the calorimeter components are reported together with the energy and time performances expected from the simulation and measured in beam tests of a small scale prototype. VL - 12 UR - https://doi.org/10.1088%2F1748-0221%2F12%2F01%2Fc01061 ER -