304 research outputs found
A telescope detection system for direct and high resolution spectrometry of intense neutron fields
A high energy- and spatial-resolution telescope detector was designed and constructed for neutron
spectrometry of intense neutron fields. The detector is constituted by a plastic scintillator coupled to a
monolithic silicon telescope (MST), in turn consisting of a DE and an E stage. The scintillator behaves as
an “active” recoil-proton converter, since it measures the deposited energy of the recoil-protons
generated across. The MST measures the residual energy of recoil-protons downstream of the converter
and also discriminates recoil-protons from photons associated to the neutron field. The lay-out of
the scintillator/MST system was optimized through an analytical model for selecting the angular range of
the scattered protons. The use of unfolding techniques for reconstructing the neutron energy distribution
was thus avoided with reasonable uncertainty (about 1.6% in neutron energy) and efficiency (of the order
of 106 counts per unit neutron fluence). A semi-empirical procedure was also developed for correcting
the non-linearity in light emission from the organic scintillator. The spectrometer was characterized with
quasi-monoenergetic and continuous fields of neutrons generated at the CN Van De Graaff accelerator of
the INFN-Legnaro National Laboratory, Italy, showing satisfactory agreement with literature data
Preliminary results of an aging test of RPC chambers for the LHCb Muon System
The preliminary results of an aging test performed at the CERN Gamma
Irradiation Facility on a single--gap RPC prototype developed for the LHCb Muon
System are presented. The results are based on an accumulated charge density of
0.42 C/cm^2, corresponding to about 4 years of LHCb running at the highest
background rate. We observe a rise in the dark current and noise measured with
source off. The current drawn with source on steadily decreased, possibly
indicating an increase of resistivity of the chamber plates. The performance of
the chamber, studied with a muon beam under several photon flux values, is
found to still fulfill the LHCb operation requirements.Comment: 4 pages, 6 figures, presented at RPC2001, VIth Workshop on Resistive
Plate Chambers and Related Detectors, November 26-27 2001, Coimbra, Portuga
First results from an aging test of a prototype RPC for the LHCb Muon System
Recent results of an aging test performed at the CERN Gamma Irradiation
Facility on a single--gap RPC prototype developed for the LHCb Muon System are
presented. The results are based on an accumulated charge of about 0.45
C/cm, corresponding to about 4 years of LHCb running at the highest
background rate. The performance of the chamber has been studied under several
photon flux values exploiting a muon beam. A degradation of the rate capability
above 1 kHz/cm is observed, which can be correlated to a sizeable increase
of resistivity of the chamber plates. An increase of the chamber dark current
is also observed. The chamber performance is found to fulfill the LHCb
operation requirements.Comment: 6 pages, 9 figures, presented at the International Workshop on Aging
Phenomena in Gaseous Detectors'', DESY-Hamburg (Germany), October 200
First evaluation of neutron induced single event effects on the CMS barrel muon electronics
Neutron irradiation tests of the currently available electronics for the CMS barrel muon detector were performed using Thermal and fast neutrons at E< 11MeV. The Single Event Upset rate on the Static RAM was measured, while upper limits are derived for events having experienced no failure. The results are used to guess the upper limits on the mean time between failures in the whole barrel muon detector
New results from an extensive aging test on bakelite Resistive Plate Chambers
We present recent results of an extensive aging test, performed at the CERN
Gamma Irradiation Facility on two single--gap RPC prototypes, developed for the
LHCb Muon System. With a method based on a model describing the behaviour of an
RPC under high particle flux conditions, we have periodically measured the
electrode resistance R of the two RPC prototypes over three years: we observe a
large spontaneous increase of R with time, from the initial value of about 2
MOhm to more than 250 MOhm. A corresponding degradation of the RPC rate
capabilities, from more than 3 kHz/cm2 to less than 0.15 kHz/cm2 is also found.Comment: 6 pages, 7 figures, presented at Siena 2002, 8th Topical Seminar on
Innovative Particle and Radiation Detectors 21-24 October 2002, Siena, Ital
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