Development of hybrid low-pressure MSGC neutron detectors

Abstract

For very high rate and resolution time-resolved experiments at next generation pulsed spallation neutron sources like ESS large-area hybrid low-pressure micro-strip gas chamber detectors are being developed. Due to their thin composite converter foil and exponential gas multiplication commencing at the converter surfaces the detectors are free of parallax, and according to detailed modeling the very high transverse and longitudinal localization accuracies in the conversion and gas multiplication processes allow position and time resolutions of ∼100 μm and <10 ns FWHM for thermal neutrons, respectively, the latter limited by the transit time through the converter. In the European R&D project TECHNI for this detector an advanced delay line readout technology with multi-event readout was developed as an economical solution for the majority of applications, which, however, limits the position resolution and rate capability to <0.3 mm and 1–2 Mcps, respectively. Therefore, in the successor project DETNI a dedicated ASIC family is being developed for achieving position resolutions of ∼100 μm FWHM and counting rates of ∼10 8 cps. This will open up novel applications based on time-of-flight (TOF) and single-event detection with very high dynamic range, replacing integrating CCD and image plate detectors, e.g. in radiography/tomography, TOF Laue diffraction, single crystal diffraction and focusing low- Q SANS. In this conference report new results concerning the technical realization of this detector system are reported in conjunction with a brief summary of the detector principle and with reference to earlier results.