International Topical Meeting on Nuclear Research Applications and Utilization of Accelerators

4-8 May 2009, Vienna

New Detector for Neutron Beam Monitor

S. Andriamonje¹, M. Brugger¹, P. Cennini¹, R. De Oliveira¹, Y. Kadi¹, M. Lazzaroni¹, E. Lebbos¹, R. Losito¹, R. Rocca¹, V. Vlachoudis¹,W. Vollenberg¹, P. Schillebeeckx², P. Siegler², R. Sarmento³, E. Berthoumieux⁴, A. Giganon⁴, Y. Giomataris⁴, F. Gunsing⁴, M. Calviani⁵, N. Colonna⁵, and the n_TOF collaboration

¹CERN, Geneva, Switzerland
²IRMM Geel, Belgium
³ITN Lisboa, Portugal
⁴CEA Saclay, France
⁵INFN Bari, Italy

Corresponding Author: Samuel.Andriamonje@cern.ch

For high precision of the neutron cross-section measurement, one of a very important and fundamental parameter is the knowledge of the neutron flux during the measurements. The detector dedicated for this measurement must be placed in the entrance of the experimental area before the different detectors for the neutron-cross section measurement. That means the device used for this detector should present a mass as small as possible, in order to minimize the perturbation on the neutron beam and, especially, the background produced by the device itself. According to these considerations a new neutron detector equipped with a small-mass device based on micromegas microbulk technology has been designed for monitoring the CERN n_TOF neutron beam. In order to cover the full range of the neutron energy from thermal to several MeV two neutron/ charged particle converter (²³⁵U and ¹⁰B) have been used. The ²³⁵U(n, f) is suited above a few 100 eV. Below that energy the resonance structure of ²³⁵U(n, f) does not allow a precise determination of the neutron flux. To fill this gap the ¹⁰B(n, α) is simultaneously used. After a description of the innovative detector concept, we present the result obtained in the IRMM Geel neutron beam facility and the preliminary commissioning of the new device of the CERN n_TOF facility.

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