Design and assembly status overview of the Mu2e electromagnetic calorimeter mechanical structures
Year: 2025
Authors: Atanov N., Baranov V., Benedetti E., Bloise C., Borrel L., Ceravolo S., Cervelli F., Colao F., Cordelli M., Corradi G., Davydov YI., Di Falco S., Diociaiuti E., Donati S., Echenard B., Fedeli P., Ferrari C., Gioiosa A., Giovannella S., Giusti V., Glagolev V., Hampai D., Happacher F., Hitlin DG., Martini M., Middleton S., Miscetti S., Morescalchi L., Paesani D., Pasciuto D., Pedreschi E., Porter F., Raffaelli F., Saputi A., Sarra I., Spinella F., Taffara A., Zhu RY.
Autors Affiliation: Joint Inst Nucl Res, Dubna, Russia; INFN, Sez Roma, Rome, Italy; Lab Nazl Frascati INFN, Frascati, Italy; CALTECH, Pasadena, CA USA; ENEA, Frascati, Italy; INFN Sez Pisa, Pisa, Italy; Univ Pisa, Pisa, Italy; CNR INO, Pisa, Italy; Univ Molise, Campobasso, Italy; Univ Roma Tor Vergata, Rome, Italy; Univ Guglielmo Marconi, Rome, Italy; Lab Nazl Sud IN FN, Catania, Italy; INFN, Sez Ferrara, Ferrara, Italy.
Abstract: The ��muon-to-electron conversion�� (Mu2e) experiment at Fermilab will search for the Charged Lepton Flavour Violating neutrino-less coherent conversion of a muon into an electron in the field of an aluminum nucleus. The observation of this process would be the unambiguous evidence of physics beyond the Standard Model. The detector has been designed as a state-of-the-art crystal calorimeter and employs 1348 pure Cesium Iodide (CsI) crystals readout by UV-extended silicon photosensors and fast front-end and digitization electronics. A design consisting of two identical annular matrices (named ��disks��) positioned at the relative distance of 70 cm, downstream the aluminum target along the muon beamline, satisfies the Mu2e physics requirements. The hostile Mu2e operational conditions, in terms of radiation levels (total ionizing dose of 90 krad and a neutron fluence of 5×10(12) n/cm(2)@1MeV eq(Si)/y), magnetic field intensity (1 T) and vacuum level (10(-4) Torr) have posed tight constraints on the design of the detector mechanical structures and materials choice. The support structure of the two 674 crystal matrices employs two aluminum hollow rings and parts made of open-cell vacuum-compatible carbon fiber. The photosensors and service front-end electronics for each crystal are assembled in a unique mechanical unit inserted in a machined copper holder. The 674 units are supported by a machined plate made of vacuum-compatible plastic material. The plate also integrates the cooling system made of a network of copper lines flowing a low temperature radiation-hard fluid and placed in thermal contact with the copper holders. The data acquisition electronics is hosted in aluminum custom crates positioned on the external lateral surface of the two disks. The crates also integrate the electronics cooling system.
Journal/Review: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT
Volume: 1070 Pages from: 170040-1 to: 170040-3
More Information: We are grateful for the vital contributions of the Fermilab staff and the technical staff of the participating institutions. This work was supported by the US Department of Energy; the Istituto Nazionale di Fisica Nucleare, Italy; the Science and Technology Facilities Council, UK; the Ministry of Education and Science, Russian Federation; the National Science Foundation, USA; the Thousand Talents Plan, China; the Helmholtz Association, Germany; and the EU Horizon 2020 Research and Innovation Program under the Marie Sklodowska-Curie Grant Agreement No. 734303, 822185, 858199, 101003460, 101006726. This document was prepared by members of the Mu2e Collaboration using the resources of the Fermi National Accelerator Laboratory (Fermilab), a U.S. Department of Energy, Office of Science, HEP User Facility. Fermilab is managed by Fermi Research Alliance, LLC (FRA), acting under Contract No. DE-AC02-07CH11359.
KeyWords: Detector; Mu2e; Calorimetry; Fermilab; CLFV; Mechanics; Cooling; Structures
DOI: 10.1016/j.nima.2024.170040
