International Topical Meeting on Nuclear Research Applications and Utilization of Accelerators

4-8 May 2009, Vienna

Commissioning of the New Spallation Target for the n_TOF facility at CERN

S. Andriamonje, Y. Body, M. Brugger, P. Cennini, A. Ferrari, L. Ferreira, L. Gatignon, D. Grenier, Y. Kadi, E. Lebbos, R. Losito, S. Marque, D. Ramos, S. Sgobba, V. Vlachoudis, and the n_TOF collaboration

CERN, Geneva, Swizerland

Corresponding Author: Vasilis.Vlachoudis@cern.ch

The neutron Time of Flight (n_TOF) facility at CERN is a source of high flux of neutrons obtained by the spallation process of 20 GeV/c protons onto a solid lead target and the remarkable beam density of the Protons Synchrotron (PS). From Nov 2008 the n_TOF facility resumed operation after a halt of 4 years due to radio-protection issues. It features a new lead spallation target with a more robust design, more efficient cooling, separate moderator circuit and most important without any loss of the unique neutron performances of the previous target. The outstanding characteristics of this facility: high neutron flux 10⁶n/cm/s.c. at 185 m, wide spectral function from thermal up to GeV, low repetition rates 1.2 s^-1 1 and the excellent energy resolution of 2 x 10⁴ open new possibilities for high precision cross section measurements, using radioactive samples of modest mass. Moreover the separate moderator circuit will permit in the future the use of borated or heavy water instead of normal water to reduce the 2.2 MeV γ background for the neutron capture measurements. The facility has been commissioned in Nov. 2008, with performances similar of the previous target and predicted by Monte Carlo simulations.

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