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Abstract We present the first prototype of a novel thermal neutron detector using the time projection method. The system consists of 8 TimePix ASICs with postprocessed InGrid meshes. Each ASIC has 256 × 256 pixels of 55 µm × 55 µm in size with the capability to measure charge or time. This allows to visualize entire conversion particle tracks with their spatial and time information and, by using event reconstruction algorithms, discriminate against the background of others. By using the Scalable Readout System the detector as presented here could also be upscaled to much larger active areas. In the current configuration with a B 4 10 C layer of 1 μ m thickness aligned in parallel to the readout we could achieve in Ar: C O 2 80:20 a spatial resolution of σ = (115 ± 8) μ m. [ABSTRACT FROM AUTHOR]

Cosmic-Ray Neutron Sensing (CRNS) is a novel technique for determining environmental water content by measuring albedo neutrons in the epithermal to fast energy range with moderated neutron detectors. We have investigated the response function of stationary and mobile neutron detectors typically used for environmental research in order to improve the model accuracy for neutron transport studies. Monte Carlo simulations have been performed in order to analyze the detection probability in terms of energy-dependent response and angular sensitivity for different variants of CRNS detectors and converter gases. Our results reveal the sensor’s response to neutron energies from 0.1 eV to 1 0 6 eV and highest sensitivity to vertical fluxes. The detector efficiency shows good agreement with reference data from the structurally similar Bonner Spheres. The relative probability of neutrons contributing to the overall integrated signal is especially important in regions with non-uniform albedo fluxes, such as complex terrain or heterogeneous distribution of hydrogen pools. [ABSTRACT FROM AUTHOR]

We report on the CASCADE project – a detection system, which has been designed for the purposes of neutron Spin Echo spectroscopy and which is continuously further developed and adapted to various applications. It features 2D spatially resolved detection of thermal neutrons at high rates. The CASCADE detector is composed of a stack of solid 10 B coated Gas Electron Multiplier foils, which serve both as a neutron converter and as an amplifier for the primary ionization deposited in the standard counting gas environment. This multi-layer setup efficiently increases the detection efficiency and by extracting the signal of the charge traversing the stack the conversion layer can be identified allowing a precise determination of the time-of-flight. The spatial resolution is found by optical contrast determination to be σ = ( 1.39 ± 0.05 ) mm and by divergence corrected aperture measurements σ = ( 1.454 ± 0.007 ) mm , which is in agreement with the simulated detector model. Furthermore this enabled to investigate and describe the non-Gaussian resolution function. At the HEiDi diffractometer the absolute detection efficiency has been studied. At 0.6 Å for the 6 layer detector, which is currently part of the RESEDA spectrometer, an efficiency of 7.8% has been measured, which by means of Monte Carlo simulations translates to (21.0±1.5)% for thermal neutrons at 1.8 Å and (46.9±3.3)% at 5.4 Å. [ABSTRACT FROM AUTHOR]

Abstract: The 10B based Jalousie detector is a replacement for 3He counter tubes, which are nowadays less affordable for large area detectors due to the 3He crisis. In this paper we investigate and verify the performance of the new 10B based detector concept and its adoption for the POWTEX diffractometer, which is designed for the detection of thermal neutrons with predicted detection efficiencies of 75–50% for neutron energies of 10–100meV, respectively. The predicted detection efficiency has been verified by absolute measurements using neutrons with a wavelength of 1.17Å (59meV). [Copyright &y& Elsevier]