The MEG experiment at the Paul Scherrer Institut (PSI) represents the state of the art in the search for the charged Lepton Flavor Violating decay, setting the most stringent upper limit on the BR (90% C.L.). An upgrade of MEG, MEG II, was designed, commissioned and recently started the physics data taking. Its goal is to reach a sensitivity level of . In order to reconstruct the positron momentum vector a Cylindrical Drift CHamber (CDCH) with unprecedented peculiarities was built, featuring angular and momentum resolutions at the 6.5 mrad and 100 keV/c level. The CDCH is a 2-meter long, 60 cm in diameter, low-mass, single volume detector with high granularity: 9 layers of 192 drift cells, few mm wide, defined by wires in a stereo configuration for longitudinal hit localization. The filling gas mixture is Helium:Isobutane 90:10. The total radiation length is X, thus minimizing the Multiple Coulomb Scattering and allowing for a single-hit resolution . After the assembly at INFN Pisa, the CDCH was transported to PSI and integrated into the MEG II experimental apparatus since 2018. The commissioning phase lasted for the past three years until the operational stability was reached in 2020. The analysis software is continuously developing and the tuning of the reconstruction algorithms is one of the main activities. The latest updates on the positron momentum vector resolutions and tracking efficiency are presented.

The cylindrical drift chamber of the MEG II experiment / Chiappini, M.; Baldini, A. M.; Benmansour, H.; Cavoto, G.; Cei, F.; Chiarello, G.; Corvaglia, A.; Cuna, F.; Maso, G. Dal; Francesconi, M.; Galli, L.; Grancagnolo, F.; Grassi, M.; Hildebrandt, M.; Ignatov, F.; Meucci, M.; Miccoli, A.; Molzon, W.; Nicolò, D.; Oya, A.; Palo, D.; Panareo, M.; Papa, A.; Raffaelli, F.; Renga, F.; Schwendimann, P.; Signorelli, G.; Tassielli, G. F.; Uchiyama, Y.; Venturini, A.; Vitali, B.; Voena, C.. - In: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH. SECTION A, ACCELERATORS, SPECTROMETERS, DETECTORS AND ASSOCIATED EQUIPMENT. - ISSN 0168-9002. - (2022), p. 167740. [10.1016/j.nima.2022.167740]

The cylindrical drift chamber of the MEG II experiment

Cavoto, G.
Membro del Collaboration Group
;
Meucci, M.
Membro del Collaboration Group
;
Raffaelli, F.;Vitali, B.;Voena, C.
2022

Abstract

The MEG experiment at the Paul Scherrer Institut (PSI) represents the state of the art in the search for the charged Lepton Flavor Violating decay, setting the most stringent upper limit on the BR (90% C.L.). An upgrade of MEG, MEG II, was designed, commissioned and recently started the physics data taking. Its goal is to reach a sensitivity level of . In order to reconstruct the positron momentum vector a Cylindrical Drift CHamber (CDCH) with unprecedented peculiarities was built, featuring angular and momentum resolutions at the 6.5 mrad and 100 keV/c level. The CDCH is a 2-meter long, 60 cm in diameter, low-mass, single volume detector with high granularity: 9 layers of 192 drift cells, few mm wide, defined by wires in a stereo configuration for longitudinal hit localization. The filling gas mixture is Helium:Isobutane 90:10. The total radiation length is X, thus minimizing the Multiple Coulomb Scattering and allowing for a single-hit resolution . After the assembly at INFN Pisa, the CDCH was transported to PSI and integrated into the MEG II experimental apparatus since 2018. The commissioning phase lasted for the past three years until the operational stability was reached in 2020. The analysis software is continuously developing and the tuning of the reconstruction algorithms is one of the main activities. The latest updates on the positron momentum vector resolutions and tracking efficiency are presented.
2022
Muon; charged lepton flavour violation; drift chamber; gas detector
01 Pubblicazione su rivista::01a Articolo in rivista
The cylindrical drift chamber of the MEG II experiment / Chiappini, M.; Baldini, A. M.; Benmansour, H.; Cavoto, G.; Cei, F.; Chiarello, G.; Corvaglia, A.; Cuna, F.; Maso, G. Dal; Francesconi, M.; Galli, L.; Grancagnolo, F.; Grassi, M.; Hildebrandt, M.; Ignatov, F.; Meucci, M.; Miccoli, A.; Molzon, W.; Nicolò, D.; Oya, A.; Palo, D.; Panareo, M.; Papa, A.; Raffaelli, F.; Renga, F.; Schwendimann, P.; Signorelli, G.; Tassielli, G. F.; Uchiyama, Y.; Venturini, A.; Vitali, B.; Voena, C.. - In: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH. SECTION A, ACCELERATORS, SPECTROMETERS, DETECTORS AND ASSOCIATED EQUIPMENT. - ISSN 0168-9002. - (2022), p. 167740. [10.1016/j.nima.2022.167740]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1659841
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