CERN Accélérateur de science

Preprint
Report number	ARDENT-CONF-2012-001
Title	Performance Test of a Triple GEM Detector at CERN n_TOF Facility
Author(s)	Claps, Gerardo (INFN-LNF) ; Croci, Gabriele (IFP, Milan) ; Murtas, Fabrizio (CERN ; Frascati) ; Pietropaolo, Antonino (IFP, Milan) ; Puddu, Silvia (CERN ; Bern U., LHEP) ; Severino, Clizia Tecla (CERN ; Bern U., LHEP) ; Silari, Marco (CERN)
Publication	2012
Imprint	2012-10-31
Presented at	2012 IEEE Nuclear Science Symposium and Medical Imaging Conference, Anaheim, California, USA, 29 Oct - 3 Nov 2012
Subject category	Detectors and Experimental Techniques
ARDENT category	GEM
Accelerator/Facility, Experiment	CERN PS ; nTOF
Keywords	GEM ; n_TOF ; fast neutrons detection
Abstract	The application of a triple GEM (Gas Electron Multiplier) for neutron detection was tested at the n_TOF facility at CERN. n_TOF allows the neutron energy distribution to be measured via a  185 m time of flight path. A 20 GeV/c proton beam hits a lead target generating a neutron spectrum ranging from thermal energies to the GeV region. Due to their long flight path and short proton pulse, the neutron arrival times at the experimental area define their energy (1). A triple GEM detector with a 60 μm Polyethylene (PE) neutron converter and 40 μm of Aluminium, filled with an Ar-CO2 70-30% mixture, was installed a few meters downstream of the experimental area, just in front of the beam dump. The measurements were purely parasitic; they were conducted in parallel and without interfering with the official n_TOF scientific program. Using the n_TOF trigger it is possible to synchronize the GEM data acquisition in order to select a given neutron energy window and measure the detector efficiency as a function of neutron energy. Changing the detector gain, it is possible to perform these measurements with a low gamma-background level. Thanks to the pixelated read-out the neutron beam spot and the efficiency of the detector have been measured.
Submitted by	[email protected]