CERN Accelerating science

Internal Note
Report number	SL-Note-2001-046-EET
Title	Study of the background in the measuring station at the n_TOF facility at CERN: sources and solutions
Author(s)	Zanini, L ; Abbondanno, U ; Aerts, G ; Andriamonje, Samuel A ; Andrzejewski, J ; Angelopoulous, A ; Assimakopoulos, Panayiotis ; Bacri, C-O ; Badurek, G ; Berthoumieux, E ; Baumann, P ; Beer, H ; Benlliure, J ; Berthier, B ; Bondarenko, I ; Borcea, C ; Bos, A J J ; Boscolo-Marchi, E ; Bustreo, N ; Calviño, F ; Cano-Ott, D ; Capote, R ; Carlson, P ; Charpak, Georges ; Chauvin, N ; Cennini, P ; Chepel, V ; Colonna, N ; Cortés, G ; Cortina-Gil, D ; Corvi, F ; Cusmano, A ; Dababneh, S ; Dahlfors, M ; Damianoglou, D ; David, S ; Dimovasili, E ; Domingo, C ; Doroshenko, A ; Duran-Escribano, I ; Eleftheriadis, C ; Embid, M ; Ferrant, L ; Ferrari, A ; Ferreira-Marques, R ; Frais-Kölbl, H ; Furman, W ; Fursov, B ; Garzón, J A ; Giomataris, Ioanis ; Gledenov, Y ; Gonzalez-Romero, E ; Goverdovski, A ; Gramegna, F ; Griesmayer, E ; Gunsing, F ; Haefner, P ; Haight, R ; Heil, M ; Herrera-martinez, A ; Hollander, P ; Ioannou, P ; Isaev, S ; Jericha, E ; Kadi, Y ; Kappeler, F ; Karadimos, D ; Karamanis, D ; Kayukova, A ; Kazakov, L ; Kelic, A ; Ketlerov, V ; Kitis, G ; Köhler, P E ; Kopach, Y ; Kossionides, E ; Kroshkina, I ; Lacoste, V ; Lamboudis, C ; Leeb, H ; Leprêtre, A ; Lopes, M ; Lozano, M ; Marrone, S ; Martínez-Val, J M ; Mastinu, P ; Mengoni, A ; Meunier, R ; Mezentsev, A J ; Milazzo, P ; Minguez, E ; Mitrofanov, V ; Moreau, C ; Müller, A ; Nicolis, N ; Nikolenkov, V ; Oberhummer, Heinz ; Pakou, A ; Pancin, J ; Papadopoulous, K ; Papaevangelou, T ; Paradela, C ; Paradelis, T ; Pavlik, A ; Pavlopoulos, P ; Perrez-Parra, A ; Perriale, L ; Perlado, J M ; Peskov, Vladimir ; Piksaikin, V ; Plag, R ; Plompen, A ; Plukis, A ; Poch, A ; Policarpo, Armando ; Popov, A ; Popov, Y P ; Pretel, C ; Quesada, J M ; Radermacher, E ; Rapp, W ; Rauscher, T ; Reifarth, R ; Rejmund, F ; Rubbia, Carlo ; Rudolf, G ; Rullhusen, P ; Sakelliou, L ; Saldaña, F ; Samylin, B ; Savvidis, I ; Savvidis, S ; Sedyshev, P ; Stéphan, C ; Szalanski, P ; Tagliente, G ; Taín, J L ; Tapia, C ; Tassan-Got, L ; Terchychnyi, R ; Tsabaris, C ; Tsangas, N ; van Eijk, C W E ; Vannini, G ; Ventura, A ; Villamarin, A ; Vlachoudis, V ; Vlastou, R ; Voinov, A ; Voss, F ; Wendler, H ; Wiescher, M ; Wisshak, K ; Zanini, L ; Zeinalov, S ; Zhuravlev, B
Affiliation	(Technische Univ., Wien, Austria) ; (Univ. Wien, Austria) ; (Fachhochschule Wr. Neustadt, Wien, Austria) ; (CERN) ; (CSNSM, Orsay, France) ; (IPN, Orsay, France) ; (IreS, Strasbourg, France) ; (DSM, Gif-sur-Yvette, France) ; (Inst. für Kernphysik, Germany) ; (Univ. of Athens, Greece) ; (Technical Univ. of Athens, Greece) ; (NCSR, Athens, Grece) ; (Univ. of Ioannina, Greece) ; (Univ. of Thessaloniki, Greece) ; (Univ. of Thrace, Greece) ; (ENEA, Bologna, Italy) ; (Laboratori Nazionali di Legnaro, Italy) ; (INFN, Bari, Italy) ; (INFN, Trieste, Italy) ; (Univ. degli Studi Pavia, Pavia, Italy) ; (IRMM, Geel, Belgium) ; (Univ. of Lodz, Lodz, Poland) ; (Univ. de Coimbra, Portugal) ; (Frank Laboratory of Neutron Physics, Dubna, Russia) ; (Inst. of Physics and Power Engineering, Obninsk, Russia) ; (Centro de Investigaciones Energeticas Medioambientales y Technologicas, Madrid, Spain) ; (Univ. of Valencia, Spain) ; (Univ. Politecnica de Madrid, Spain) ; (Univ. de Sevilla, Spain) ; (Univ. de Santiago de Compostela, Spain) ; (Univ. Politecnica de Catalunya, Barcelona, Spain) ; (Kungliga Tekniska Hogskolan, Physics Department, Stockholm, Sweden) ; (Univ. of Basel, Basel, Switzerland) ; (Delft, The Netherlands) ; (Los Alamos National Laboratory, New Mexico, USA) ; (Oak Ridge National Laboratory, Physics Division, Oak Ridge, USA) ; (Univ. of Notre Dame, Notre Dame, USA)
Corporate Author(s)	CERN. Geneva. SPS and LHC Division
Publication	2001
Imprint	12 Dec 2001
Number of pages	35
Series	(Note)
Subject category	Accelerators and Storage Rings
Accelerator/Facility, Experiment	CERN PS ; nTOF
Free keywords	n-TOF
Abstract	A background roughly two orders of magnitude higher than tolerable was found in the n_TOF facility at CERN during the first measurements [1]. This note describes a series of additional measurements performed in the n_TOF experimental area to study the origin and the characteristics of the background. The program of these measurements was determined taking into account the results from the simulations carried out by the EET group [2]. A first phase of measurements confirmed what was expected from the simulations, namely that the dominant source of background was due to neutrons generated by negative muon capture. Actions to reduce the background were taken according to the results from both measurements and simulations. An iron shielding wall 3.2 m thick was then placed in between the sweeping magnet and the second collimator, with the purpose of stopping most of the muons. In a second phase of measurements, results showed that the additional shielding reduced the main component of the background by about a factor of 30.

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