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L. Morescalchi

Publications and source records attributed to L. Morescalchi.

23 records · Page 2Linked to original sources
arXiv2017

The calorimeter of the Mu2e experiment at Fermilab

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.

physics.ins-det↗
arXiv2016

Design and status of the Mu2e electromagnetic calorimeter

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 2.5x10^{-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 BaF2 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.

physics.ins-det↗
arXiv2016

Design, status and test of the Mu2e crystal calorimeter

The Mu2e experiment at Fermilab searches for the charged-lepton flavor violating neutrino-less conversion of a negative muon into an electron in the field of a aluminum nucleus. The dynamic of such a process is well modeled by a two-body decay, resulting in a monoenergetic electron with an energy slightly below the muon rest mass (104.967 MeV). The calorimeter of this experiment plays an important role to provide excellent particle identification capabilities and an online trigger filter while aiding the track reconstruction capabilities. The baseline calorimeter configuration consists of two disks each made with about 700 undoped CsI crystals read out by two large area UV-extended Silicon Photomultipliers. These crystals match the requirements for stability of response, high resolution and radiation hardness. In this paper we present the final calorimeter design.

physics.ins-det↗
arXiv2016

Measurement of time resolution of the Mu2e LYSO calorimeter prototype

In this paper we present the time resolution measurements of the Lutetium-Yttrium Oxyorthosilicate (LYSO) calorimeter prototype for the Mu2e experiment. The measurements have been performed using the $e^-$ beam of the Beam Test Facility (BTF) in Frascati, Italy in the energy range from 100 to 400 MeV. The calorimeter prototype consisted of twenty five 30x30x130 mm$^3$, LYSO crystals read out by 10x10 mm$^2$ Hamamatsu Avalanche Photodiodes (APDs). The energy dependence of the measured time resolution can be parametrized as $σ_{t}(E)=a/\sqrt{E/\mathrm{GeV}} \oplus b$, with the stochastic and constant terms $a=(51\pm1)$ ps and $b=(10\pm4)$ ps, respectively. This corresponds to the time resolution of ($162\pm4$) ps at 100 MeV.

physics.ins-det↗