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Discharge rate measurements for Micromegas detectors in the presence of a longitudinal magnetic field
- Source :
-
Nuclear Instruments & Methods in Physics Research Section A . Oct2011, Vol. 654 Issue 1, p135-139. 5p. - Publication Year :
- 2011
-
Abstract
- Abstract: We present first discharge rate measurements for Micromegas detectors in the presence of a high longitudinal magnetic field in the GeV kinematical region. Measurements were performed by using two Micromegas detectors and a photon beam impinging a CH2 target in the Hall B of the Jefferson Laboratory. One detector was equipped with an additional GEM foil, and a reduction of the discharge probability by two orders of magnitude compared to the stand-alone Micromegas was observed. The detectors were placed in the FROST solenoid providing a longitudinal magnetic field up to 5T. It allowed for precise measurements of the discharge probability dependence with a diffusion-reducing magnetic field. Between 0 and 5T, the discharge probability increased by a factor of 10 for polar angles between 19° and 34°. A GEANT4-based simulation developed for sparking rate calculation was calibrated against these data in order to predict the sparking rate in a high longitudinal magnetic field environment. This simulation is then used to investigate the possible use of Micromegas in the Forward Vertex Tracker (FVT) of the future CLAS12 spectrometer. In the case of the FVT a sparking rate of 1Hz per detector was obtained at the anticipated CLAS12 luminosity. [Copyright &y& Elsevier]
- Subjects :
- *NUCLEAR counters
*MAGNETIC fields
*PROBABILITY theory
*MEASUREMENT
*PHOTON beams
Subjects
Details
- Language :
- English
- ISSN :
- 01689002
- Volume :
- 654
- Issue :
- 1
- Database :
- Academic Search Index
- Journal :
- Nuclear Instruments & Methods in Physics Research Section A
- Publication Type :
- Academic Journal
- Accession number :
- 65869818
- Full Text :
- https://doi.org/10.1016/j.nima.2011.07.037