Study of the effects of radiation on the CMS Drift Tubes Muon Detector for the HL-LHC
Creators: name: Abbiendi, G.
name: Maestre, J. Alcaraz
name: Fernández, A. Álvarez
name: González, B. Álvarez
name: Amapane, N.
name: Bachiller, I.
name: Barcala, J. M.
name: Barcellan, L.
name: Battilana, C.
name: Bellato, M.
name: Bencze, G.
name: Benettoni, M.
name: Beni, N.
name: Benvenuti, A.
name: Ramos, L. C. Blanco
name: Boletti, A.
name: Bragagnolo, A.
name: Cifuentes, J. A. Brochero
name: Cafaro, V.
name: Calderon, A.
name: Calvo, E.
name: Cappati, A.
name: Carlin, R.
name: Montoya, C. A. Carrillo
name: Cavallo, F. R.
name: Ruiz, J. M. Cela
name: Cepeda, M.
name: Cerrada, M.
name: Quero, B. Chazin
name: Checchia, P.
name: Ciano, L.
name: Colino, N.
name: Corti, D.
name: Cotto, G.
name: Cuevas, J.
name: Cuffiani, M.
name: Dallavalle, G. M.
name: Dattola, D.
name: De La Cruz, B.
name: DeRemigis, P.
name: Cid, C. Erice
name: Fabbri, F.
name: Fanfani, A.
name: Fasanella, D.
name: Bedoya, C. F.
name: de Trocóniz, J. F.
name: Manteca, P. Fernandez
name: Menéndez, J. Fernández
name: Ramos, J. P. Fernández
name: Folgueras, S.
name: Fouz, M. C.
name: Ferrero, D. Francia
name: Romero, J. García
name: Gasparini, F.
name: Gasparini, U.
name: Ghosh, S.
name: Giordano, V.
name: Casademunt, F. Gomez
name: Gonella, F.
name: Caballero, I. González
name: Fernández, J. R. González
name: López, O. González
name: López, S. Goy
name: Gozzelino, A.
name: Griggio, A.
name: Grosso, G.
name: Guandalini, C.
name: Guiducci, L.
name: Gulmini, M.
name: Hebbeker, T.
name: Heidemann, C.
name: Hernández, J. M.
name: Hoepfner, K.
name: Iemmi, F.
name: Isocrate, R.
name: Josa, M. I.
name: Kiani, B.
name: Lacaprara, S.
name: Meo, S. Lo
name: Marcellini, S.
name: Margoni, M.
name: Marín, J.
name: Mariotti, C.
name: Martín, I. Martín
name: Morales, J. J. Martínez
name: Rivero, C. Martínez
name: Maselli, S.
name: Masetti, G.
name: Meneguzzo, A. T.
name: Merschmeyer, M.
name: Mocellin, G.
name: Modenese, L.
name: Molinero, A.
name: Molnar, J.
name: Montecassiano, F.
name: Moran, D.
name: Navarrete, J. J.
name: Navarria, F.
name: Tobar, Á. Navarro
name: Oller, J. C.
name: Passaseo, M.
name: Pazzini, J.
name: Pegoraro, M.
name: Pelayo, J. Puerta
name: Pelliccioni, M.
name: Philipps, B.
name: Gomez, J. Piedra
name: Angioni, G. L. Pinna
name: Pozzobon, N.
name: Presilla, M.
name: Prieels, C.
name: Primavera, F.
name: Sánchez, J. C. Puras
name: Redondo, I.
name: Ferrero, D. D. Redondo
name: Reithler, H.
name: Rodrigo, T.
name: Bouza, V. Rodríguez
name: Roemer, J.
name: Ronchese, P.
name: Rossin, R.
name: Rotondo, F.
name: Rovelli, T.
name: Cruz, S. Sánchez
name: Navas, S. Sánchez
name: Sastre, J.
name: Scodellaro, L.
name: Simonetto, F.
name: Soares, M. S.
name: Staiano, A.
name: Szillasi, Z.
name: Teyssier, D. F.
name: Toniolo, N.
name: Torassa, E.
name: Trocino, D.
name: Ujvari, B.
name: Ventura, S.
name: Cortabitarte, R. Vilar
name: Garcia, J. Vizan
name: Zanetti, M.
name: Zantis, F. P.
name: Zilizi, G.
name: Zotto, P.
Publisher: name: arXiv
Year: 2019
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: The CMS drift tubes (DT) muon detector, built for withstanding the LHC expected integrated and instantaneous luminosities, will be used also in the High Luminosity LHC (HL-LHC) at a 5 times larger instantaneous luminosity and, consequently, much higher levels of radiation, reaching about 10 times the LHC integrated luminosity. Initial irradiation tests of a spare DT chamber at the CERN gamma irradiation facility (GIF++), at large ($\sim$O(100)) acceleration factor, showed ageing effects resulting in a degradation of the DT cell performance. However, full CMS simulations have shown almost no impact in the muon reconstruction efficiency over the full barrel acceptance and for the full integrated luminosity. A second spare DT chamber was moved inside the GIF++ bunker in October 2017. The chamber was being irradiated at lower acceleration factors, and only 2 out of the 12 layers of the chamber were switched at working voltage when the radioactive source was active, being the other layers in standby. In this way the other non-aged layers are used as reference and as a precise and unbiased telescope of muon tracks for the efficiency computation of the aged layers of the chamber, when set at working voltage for measurements. An integrated dose equivalent to two times the expected integrated luminosity of the HL-LHC run has been absorbed by this second spare DT chamber and the final impact on the muon reconstruction efficiency is under study. Direct inspection of some extracted aged anode wires presented a melted resistive deposition of materials. Investigation on the outgassing of cell materials and of the gas components used at the GIF++ are underway. Strategies to mitigate the ageing effects are also being developed. From the long irradiation measurements of the second spare DT chamber, the effects of radiation in the performance of the DTs expected during the HL-LHC run will be presented.
description: 10 pages, 7 figures, to be published in JINST, editor I. Gonz\'alez Caballero