1,132 research outputs found

    Signal-to-Noise Measurements on Irradiated CMS Tracker Detector Modules in an Electron Testbeam

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    The CMS experiment at the Large Hadron Collider at CERN is in the last phase of its construction. The harsh radiation environment at LHC will put strong demands in radiation hardness to the innermost parts of the detector. To assess the performance of irradiated microstrip detector modules, a testbeam was conducted at the Testbeam 22 facility of the DESY research center. The primary objective was the signal-to-noise measurement of irradiated CMS Tracker modules to ensure their functionality up to 10 years of LHC operation. The paper briefly summarises the basic setup at the facility and the hardware and software used to collect and analyse the data. Some interesting subsidiary results are shown, which confirm the expected behaviour of the detector with respect to the signal-to-noise performance over the active detector area and for different electron energies. The main focus of the paper are the results of the signal-to-noise measurements for CMS Tracker Modules which were exposed to different radiation doses

    Pion irradiation studies of CVD diamond detectors

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    We report here the results of a test to ascertain the radiation hardness properties of CVD diamond detectors to 300 MeV/c pions. In this test, CVD diamond detectors were exposed to 8 \times 10^{13} pions per cm^2 using the high intensity pion beam at the Paul Scherrer Institut. For comparison, silicon photodiodes were exposed to similar fluences at the same time. The measurements and the dosimetry during the irradiations are described herein. As expected, the silicon devices degraded. The diamond devices showed no degradation in collected charge and no increase in leakage current

    Development of CVD diamond radiation detectors

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    Diamond is a nearly ideal material for detecting ionizing radiation. Its outstanding radiation hardness, fast charge collection and low leakage current allow a diamond detector to be used in high ra diation, high temperature and in aggressive chemical media. We have constructed charged particle detectors using high quality CVD diamond. Characterization of the diamond samples and various detect ors are presented in terms of collection distance, d=ÎŒEτd=\mu E \tau, the average distance electron-hole pairs move apart under the influence of an electric field, where ÎŒ\mu is the sum of carrier mo bilities, EE is the applied electric field, and τ\tau is the mobility weighted carrier lifetime. Over the last two years the collection distance increased from ∌\sim 75 ÎŒ\mum to over 200 ÎŒ\mu m. With this high quality CVD diamond a series of micro-strip and pixel particle detectors have been constructed. These devices were tested to determine their position resolution and signal to n oise performance. Diamond detectors were exposed to large fluences of pions, protons and neutrons to establish their radiation hardness properties. The results of these tests and their correlati on with the characterization studies are presented

    Proton Irradiation of CVD Diamond Detectors for High Luminosity Experiments at the LHC

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    CVD diamond shows promising properties for use as a position sensitive detector for experiments in the highest radiation areas at the Large Hadron Collider. In order to study the radiation hardn ess of diamond we exposed CVD diamond detector samples to 24~GeV/cc and 500~MeV protons up to a fluence of 5×1015 p/cm25\times 10^{15}~p/{\rm cm^2}. We measured the charge collection distance, the ave rage distance electron hole pairs move apart in an external electric field, and leakage currents before, during, and after irradiation. The charge collection distance remains unchanged up to 1 times1015 p/cm21\ times 10^{15}~p/{\rm cm^2} and decreases by ≈\approx40~\% at 5×1015 p/cm25\times 10^{15}~p/{\rm cm^2}. Leakage currents of diamond samples were below 1~pA before and after irradiation. The particle indu ced currents during irradiation correlate well with the proton flux. In contrast to diamond, a silicon diode, which was irradiated for comparison, shows the known large increase in leakage curren t. We conclude that CVD diamond detectors are radiation hard to 24~GeV/cc and 500~MeV protons up to at least 1×1015 p/cm21\times 10^{15}~p/{\rm cm^2} without signal loss

    Performance of irradiated CVD diamond micro-strip sensors

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    CVD diamond detectors are of interest for charged particle detection and tracking due to their high radiation tolerance. In this article we present, for the first time, beam test results from recently manufactured CVD diamond strip detectors and their behavior under low doses of electrons from a ÎČ\beta-source and the performance before and after intense (>1015/cm2>10^{15}/{\rm cm^2}) proton- and pion-irradiations. We find that low dose irradiations increase the signal-to-noise ratio (pumping of the signal) and slightly deteriorate the spatial resolution. Intense irradiations with protons (2.2×1015 p/cm22.2\times 10^{15}~p/{\rm cm^2}) lowers the signal-to-noise ratio slightly. Intense irradiation with pions (2.9×1015 π/cm22.9\times 10^{15}~\pi/{\rm cm^2}) lowers the signal-to-noise ratio more. The spatial resolution of the diamond sensors improves after irradiations
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