75 research outputs found
A CdZnTe pixel detector for bone densitometry
No full textWe are building a CdZnTe pixel array detector for bone densitometry applications. In parallel with the construction, we are making a detailed simulation of the detector and of the signal development inside the crystal
Final results from the appearance search in the NOMAD experiment
No full textAn updated analysis of the full NOMAD data corresponding to approx 1.35 x 10 sup 6 charged current interactions has been performed to search for neutrino oscillations through nu subtau appearance. This document updates the recently published results on the nu submu -> nu subtau and nu submu -> nu sub e oscillations search in NOMAD with a unified analysis of the hadronic channels
Measurement of the Λ Polarization in ν_μ Charged Current Interactions in the NOMAD Experiment
No full textF.J.P. Soler h;t G. Sozzi D. Steele b;i U. Stiegler M. Stipcevi'c Th. Stolarczyk M. Tareb-Reyes G.N. Taylor V. Tereshchenko A. Toropin A.-M. Touchard S.N. Tovey h;k M.-T. Tran E. Tsesmelis J. Ulrichs L. Vacavant M. Valdata-Nappi d;1 V. Valuev f;j F. Vannucci K.E. Varvell M. Veltri V. Vercesi G. Vidal-Sitjes J.-M. Vieira T. Vinogradova F.V. Weber c;h T. Weisse F.F. Wilson L.J. Winton B.D. Yabsley H. Zaccone K. Zuber P. Zuccon LAPP, Annecy, France Johns Hopkins Univ., Baltimore, MD, USA Harvard Univ., Cambridge, MA, USA Univ. of Calabria and INFN, Cosenza, Italy Dortmund Univ., Dortmund, Germany JINR, Dubna, Russia Univ. of Florence and INFN, Florence, Italy CERN, Geneva, Switzerland University of Lausanne, Lausanne, Switzerland UCLA, Los Angeles, CA, USA University of Melbourne, Melbourne, Australia Inst. Nucl. Research, INR Moscow, Russia Univ. of Padova and INFN, Padova, Italy LPNHE, Univ. of
The HARP Time Projection Chamber
No full textA novel apparatus for the calibration of the HARP Time Projection Chamber has been designed, developed and built. The apparatus consists of a large number of point-like photo-electron sources located at precise positions inside the detector volume. The photo-electron sources are optical quartz fibers on which one end is coated with an aluminum layer of 80{\AA} thickness and are held in place on the High Voltage membrane. The fibers are used to guide UV laser light pulses that generate photoelectrons on the fiber tips and these act as photo-electron emitters. The photoelectrons drift inside the detector and produce the calibration signals. The technique allows to asses distortions and to measure drift velocity, ion feedback and time stability in real time. The analog signals generated by the TPC front-end electronics have been characterized. Different methods to extract the amplitude and time of occurrence from the digitized signals have been studied and compared. Fast estimators, like the sum of all the discrete amplitude measurements inside one pulse, show a reconstructed amplitude and time of occurrence resolution comparable to those achieved by fitting the discrete amplitude measurements to the expected pulse shapes. The obtained relative resolutions (5\%) are limited by the aliasing effect and can be improved by an order of magnitude (up to 0.3\%) by applying a correction to the estimators valu e which is constructed from the knowledge of the response of the preamplifier and the digitization procedure. An undesired cross-talk effect in the TPC front-end electronics has been found and traced to a capacitive coupling between the input and output of the preamplifiers. The cross-talk analog signals have an area which is, on average, 5\% of that of the inducing signal. However, because of the different pulse shape, after the digitization process, these cross-talk signals can produce areas which reach 25\% that of the original signal. A model has been identified, developed and tested to achieve a reduction of one order of magnitude in the cross-talk intensity
Performance of the NOMAD-STAR detector
No full textThe NOMAD-STAR detector is a silicon vertex detector installed in the NOMAD spectrometer at the CERN SPS neutrino beam. It consists of four layers of a passive boron carbide target with a total mass of 45 kg and five layers of 600 single-sided silicon microstrip detectors covering a total area of 1.14 m<sup>2</sup>. About 11,500 ν<sub>μ</sub> charged current interactions were reconstructed in the fiducial volume of NOMAD-STAR from the neutrino run in 1998. The potential use of silicon detectors for ν<sub>μ</sub>(ν<sub>e</sub>) lt - gt ν<sub>τ</sub> oscillations depends on the observation of the τ candidates by the experimental signature of a large impact parameter, in the case of the one prong decay of the τ, or a double vertex, in the case of the three prong decay. The main aim of NOMAD-STAR is to measure the impact parameter and vertex distributions of charged current interactions, which constitute the main backgrounds for the oscillation signals, to understand the significance of a potential signal in a future experiment. The present paper describes the experience gained in the operation of this silicon vertex detector, and the performance achieved with it
Performance of the LHCb RICH photodetectors in a charged particle beam
No full textThe Ring Imaging Cherenkov detectors of LHCb will use pixel Hybrid Photon Detectors to measure the spatial position of Cherenkov photons. The first six pre-production photon detectors have been tested in a beam, together with prototypes of the on-detector electronics. The tests were performed at CERN using 10 GeV / c pions together with an N2 gas radiator as a source of Cherenkov light. With 1.1 m of radiator, around 10 photoelectrons were detected per track. The single-photon Cherenkov angle resolution was measured to be 1.66 ± 0.03 mrad, which is dominated by the pixelisation of the photon detector in the test-beam set-up. Both numbers agree with expectations. © 2007 Elsevier B.V. All rights reserved
PROPOSAL TO STUDY HELIUM INDUCED HADRON PRODUCTION FOR THE ATMOSPHERIC-NEUTRINO FLUX
No full textCERN-SPSC-2001-016, CERN-SPSC-P-315-ADD-
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