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Title: Design and status of the Mu2e electromagnetic calorimeter

Here, the Mu2e experiment at Fermilab aims at measuring the neutrinoless conversion of a negative muon into an electron and reach a single event sensitivity of 2.5×10 –17 after three years of data taking. The monoenergetic electron produced in the final state, is detected by a high precision tracker and a crystal calorimeter, all embedded in a large superconducting solenoid (SD) surrounded by a cosmic ray veto system. The calorimeter is complementary to the tracker, allowing an independent trigger and powerful particle identification, while seeding the track reconstruction and contributing to remove background tracks mimicking the signal. In order to match these requirements, the calorimeter should have an energy resolution of O(5)% and a time resolution better than 500 ps at 100 MeV. The baseline solution is a calorimeter composed of two disks of BaF 2 crystals read by UV extended, solar blind, Avalanche Photodiode (APDs), which are under development from a JPL, Caltech, RMD consortium. In this paper, the calorimeter design, the R&D; studies carried out so far and the status of engineering are described. A backup alternative setup consisting of a pure CsI crystal matrix read by UV extended Hamamatsu MPPC's is also presented.
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  1. Joint Institute for Nuclear Research, Dubna (Russia)
  2. INFN Sezione di Pisa, Pisa (Italy)
  3. Lab. Nazionali di Frascati dell INFN, Frascati (Italy)
  4. INFN Sezione di Pisa, Pisa (Italy); Univ. de Pisa, Pisa (Italy)
  5. Lab. Nazionali di Frascati dell INFN, Frascati (Italy); Univ. degli studi Roma Tre, Roma (Italy)
  6. California Inst. of Technology (CalTech), Pasadena, CA (United States)
  7. INFN Sezione di Lecce, Lecce (Italy)
  8. Lab. Nazionali di Frascati dell INFN, Frascati (Italy); Univ. "Guglielmo Marconi", Roma (Italy)
  9. INFN Sezione de Pisa, Pisa (Italy); Univ. di Siena, Siena (Italy)
  10. Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
  11. INFN Sezione de Pisa, Pisa (Italy); Univ. do Pisa, Pisa (Italy)
Publication Date:
Report Number(s):
FERMILAB-CONF-16-316-E; arXiv:1608.02652
Journal ID: ISSN 0168-9002; 1480186
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment
Additional Journal Information:
Journal Volume: 824; Journal Issue: C; Journal ID: ISSN 0168-9002
Research Org:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
Country of Publication:
United States
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; calorimetry; scintillating crystals; Avalanche photodiodes; silicon photomultipliers; Lepton flavour violation
OSTI Identifier: