First studies of electron transport along small gas gaps of novel foil radiation converters for fast-neutron detectors

M. Cortesi, Robert Zboray, R. Adams, V. Dangendorf, A. Breskin, S. Mayer, H. Hoedlmoser, H. -M Prasser

    Research output: Contribution to journalArticle

    8 Citations (Scopus)

    Abstract

    Novel high-efficiency fast-neutron detectors were suggested for fan-beam tomography applications. They combine multi-layer polymer converters in gas medium, coupled to thick gaseous electron multipliers (THGEM). Neutron-induced scattering on the converter's hydrogen nuclei results in gas ionization by the escaping recoil-protons between two successive converters. The electrons drift under the action of a homogeneous electric field, parallel to the converter-foil surfaces, towards a position-sensitive THGEM multiplying element. In this work we discuss the results of a systematic study of the electron transport inside a narrow gap between successive converter foils, which affects the performance of the detector, both in terms of detection efficiency and localization properties. The efficiency of transporting ionization electrons was measured along a 0.6 mm wide gas gap in 6 and 10 mm wide polymer converters. Computer simulations provided conceptual understanding of the observations. For drift lengths of 6 mm, electrons were efficiently transported along the narrow gas gap with minimal diffusion-induced losses; an average collection efficiency of 95% was achieved for ionization electrons induced by few keV photoelectrons. The 10 mm height converter yielded considerably lower efficiency due to electrical and mechanical flaws of the converter foils. The results indicate that detection efficiencies of ∼ 7% can be expected for 2.5 MeV neutrons with 300-foils converters, of 6 mm height, 0.4 mm thick foils and 0.6 mm gas gap.

    Original languageEnglish (US)
    Article numberP01016
    JournalJournal of Instrumentation
    Volume8
    Issue number1
    DOIs
    StatePublished - Jan 1 2013

    Fingerprint

    Neutron detectors
    neutron counters
    Electron Transport
    fast neutrons
    Neutron
    Converter
    Metal foil
    converters
    foils
    Radiation
    Detector
    radiation
    Gases
    gases
    Electron
    Electron multipliers
    electrons
    Electrons
    Ionization
    Neutrons

    All Science Journal Classification (ASJC) codes

    • Instrumentation
    • Mathematical Physics

    Cite this

    Cortesi, M. ; Zboray, Robert ; Adams, R. ; Dangendorf, V. ; Breskin, A. ; Mayer, S. ; Hoedlmoser, H. ; -M Prasser, H. / First studies of electron transport along small gas gaps of novel foil radiation converters for fast-neutron detectors. In: Journal of Instrumentation. 2013 ; Vol. 8, No. 1.
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    abstract = "Novel high-efficiency fast-neutron detectors were suggested for fan-beam tomography applications. They combine multi-layer polymer converters in gas medium, coupled to thick gaseous electron multipliers (THGEM). Neutron-induced scattering on the converter's hydrogen nuclei results in gas ionization by the escaping recoil-protons between two successive converters. The electrons drift under the action of a homogeneous electric field, parallel to the converter-foil surfaces, towards a position-sensitive THGEM multiplying element. In this work we discuss the results of a systematic study of the electron transport inside a narrow gap between successive converter foils, which affects the performance of the detector, both in terms of detection efficiency and localization properties. The efficiency of transporting ionization electrons was measured along a 0.6 mm wide gas gap in 6 and 10 mm wide polymer converters. Computer simulations provided conceptual understanding of the observations. For drift lengths of 6 mm, electrons were efficiently transported along the narrow gas gap with minimal diffusion-induced losses; an average collection efficiency of 95{\%} was achieved for ionization electrons induced by few keV photoelectrons. The 10 mm height converter yielded considerably lower efficiency due to electrical and mechanical flaws of the converter foils. The results indicate that detection efficiencies of ∼ 7{\%} can be expected for 2.5 MeV neutrons with 300-foils converters, of 6 mm height, 0.4 mm thick foils and 0.6 mm gas gap.",
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    Cortesi, M, Zboray, R, Adams, R, Dangendorf, V, Breskin, A, Mayer, S, Hoedlmoser, H & -M Prasser, H 2013, 'First studies of electron transport along small gas gaps of novel foil radiation converters for fast-neutron detectors', Journal of Instrumentation, vol. 8, no. 1, P01016. https://doi.org/10.1088/1748-0221/8/01/P01016

    First studies of electron transport along small gas gaps of novel foil radiation converters for fast-neutron detectors. / Cortesi, M.; Zboray, Robert; Adams, R.; Dangendorf, V.; Breskin, A.; Mayer, S.; Hoedlmoser, H.; -M Prasser, H.

    In: Journal of Instrumentation, Vol. 8, No. 1, P01016, 01.01.2013.

    Research output: Contribution to journalArticle

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