Detection efficiency of microchannel plates for e(-) and π(-) in the momentum range from 17.5 to 345 MeV/c.
High-energy e(-) and π(-) were measured by the multichannel plate (MCP) detector at the PiM1 beam line of the High Intensity Proton Accelerator Facilities located at the Paul Scherrer Institute, Villigen, Switzerland. The measurements provide the absolute detection efficiencies for these particles: 5.8% ± 0.5% for electrons in the beam momenta range 17.5-300 MeV/c and 6.0% ± 1.3% for pions in the beam momenta range 172-345 MeV/c. The pulse height distribution determined from the measurements is close to an exponential function with negative exponent, indicating that the particles penetrated the MCP material before producing the signal somewhere inside the channel. Low charge extraction and nominal gains of the MCP detector observed in this study are consistent with the proposed mechanism of the signal formation by penetrating radiation. A very similar MCP ion detector will be used in the Neutral Ion Mass (NIM) spectrometer designed for the JUICE mission of European Space Agency (ESA) to the Jupiter system, to perform measurements of the chemical composition of the Galilean moon exospheres. The detection efficiency for penetrating radiation determined in the present studies is important for the optimisation of the radiation shielding of the NIM detector against the high-rate and high-energy electrons trapped in Jupiter's magnetic field. Furthermore, the current studies indicate that MCP detectors can be useful to measure high-energy particle beams at high temporal resolution.
Space Research and Planetary Sciences, Physics Institute, University of Bern, CH-3012 Bern, Switzerland.
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Tulej
Space Research and Planetary Sciences, Physics Institute, University of Bern, CH-3012 Bern, Switzerland.
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Meyer
Space Research and Planetary Sciences, Physics Institute, University of Bern, CH-3012 Bern, Switzerland.
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Lüthi
Space Research and Planetary Sciences, Physics Institute, University of Bern, CH-3012 Bern, Switzerland.
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D
Lasi
Space Research and Planetary Sciences, Physics Institute, University of Bern, CH-3012 Bern, Switzerland.
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Galli
Laboratory of Particle Physics, Paul Scherrer Institute, CH-5232 Villigen, Switzerland.
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Desorgher
Laboratory of Particle Physics, Paul Scherrer Institute, CH-5232 Villigen, Switzerland.
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Hajdas
Swedish Institute of Space Physics, Space Kampus 1, Kiruna, Sweden.
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Karlsson
Swedish Institute of Space Physics, Space Kampus 1, Kiruna, Sweden.
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Kalla
Space Research and Planetary Sciences, Physics Institute, University of Bern, CH-3012 Bern, Switzerland.
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Wurz