| 1. |
- Mauri, G., et al.
(författare)
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Fast neutron sensitivity of neutron detectors based on Boron-10 converter layers
- 2018
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 13:3
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Tidskriftsartikel (refereegranskat)abstract
- In the last few years many detector technologies for thermal neutron detection have been developed in order to face the shortage of He-3, which is now much less available and more expensive. Moreover the He-3-based detectors can not fulfil the requirements in performance, e.g. the spatial resolution and the counting rate capability needed for the new instruments. The Boron-10-based gaseous detectors have been proposed as a suitable choice. This and other alternative technologies are being developed at ESS. Higher intensities mean higher signals but higher background as well. The signal-to-background ratio is an important feature to study, in particular the gamma-ray and the fast neutron contributions. This paper investigates, for the first time, the fast neutrons sensitivity of B-10-based thermal neutron detector. It presents the study of the detector response as a function of energy threshold and the underlying physical mechanisms. The latter are explained with the help of theoretical considerations and simulations.
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| 2. |
- Messi, Francesco, et al.
(författare)
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The Multi-Blade : The 10B-based neutron detector for reflectometry at ESS
- 2019
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Ingår i: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. - : Elsevier BV. - 0168-9002. ; 936, s. 499-500
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Tidskriftsartikel (refereegranskat)abstract
- The Multi-Blade detector has been designed to be used on the reflectometry instruments at the upcoming European Spallation Source. It is a 10B-based gaseous detector, built as a modular stack of multi-wire proportional chambers organised on a circle around the sample. The detector has been fully characterised. The gamma and fast-neutron sensitivity has been measured at the Source Testing Facility in Lund University, Sweden; the working capability in a reflectometry instrument has been demonstrated with measurements at CRISP in ISIS, UK; and the count-rate capability of the detector will be measured the summer of 2018 at the Budapest Neutron Centre, Hungary.
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| 3. |
- Mauritzson, Nicholai, et al.
(författare)
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GEANT4-based calibration of an organic liquid scintillator
- 2022
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0168-9002. ; 1023
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Tidskriftsartikel (refereegranskat)abstract
- A light-yield calibration of an NE 213A organic liquid scintillator detector has been performed using bothmonoenergetic and polyenergetic gamma-ray sources. Scintillation light was detected in a photomultipliertube, and the corresponding pulses were subjected to waveform digitization on an event-by-event basis. Theresulting Compton edges have been analyzed using a GEANT4 simulation of the detector which models boththe interactions of the ionizing radiation as well as the transport of scintillation photons. The simulation is calibrated and also compared to well-established prescriptions used to determine the Compton edges,resulting ultimately in light-yield calibration functions. In the process, the simulation-based method produced information on the gain and intrinsic pulse-height resolution of the detector. It also facilitated a previously inaccessible understanding of the systematic uncertainties associated with the calibration of the scintillation-light yield. The simulation-based method was also compared to well-established numerical prescriptions for locating the Compton edges. Ultimately, the simulation predicted as much as 17% lower light-yield calibrations than the prescriptions. These calibrations indicate that approximately 35% of the scintillation light associated with a given gamma-ray reaches the photocathode. It is remarkable how well two 50 year old prescriptions for calibrating scintillation-light yield in organic scintillators have stood the test of time.
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| 4. |
- Scherzinger, Julius, et al.
(författare)
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A comparison of untagged gamma-ray and tagged-neutron yields from 241AmBe and 238PuBe sources
- 2017
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Ingår i: Applied Radiation and Isotopes. - : Elsevier BV. - 0969-8043 .- 1872-9800. ; 127, s. 98-102
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Tidskriftsartikel (refereegranskat)abstract
- Untagged gamma-ray and tagged-neutron yields from 241AmBe and 238PuBe mixed-field sources have been measured. Gamma-ray spectroscopy measurements from 1 to 5 MeV were performed in an open environment using a CeBr3 detector and the same experimental conditions for both sources. The shapes of the distributions are very similar and agree well with previous data. Tagged-neutron measurements from 2 to 6 MeV were performed in a shielded environment using a NE-213 liquid-scintillator detector for the neutrons and a YAP(Ce) detector to tag the 4.44 MeV gamma-rays associated with the de-excitation of the first-excited state of 12C. Again, the same experimental conditions were used for both sources. The shapes of these distributions are also very similar and agree well with previous data, each other, and the ISO recommendation. Our 238PuBe source provides approximately 2.6 times more 4.44 MeV gamma-rays and 2.4 times more neutrons over the tagged-neutron energy range, the latter in reasonable agreement with the original full-spectrum source-calibration measurements performed at the time of their acquisition.
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| 5. |
- Scherzinger, Julius, et al.
(författare)
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Tagging fast neutrons from a Cf-252 fission-fragment source
- 2017
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Ingår i: Applied Radiation and Isotopes. - : Elsevier BV. - 0969-8043 .- 1872-9800. ; 128, s. 270-274
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Tidskriftsartikel (refereegranskat)abstract
- Coincidence and time-of-flight measurement techniques are employed to tag fission neutrons emitted from a Cf-252 source sealed on one side with a very thin layer of Au. The source is positioned within a gaseous He-4 scintillator detector. Together with a particles, both light and heavy fission fragments pass through the thin layer of Au and are detected. The fragments enable the corresponding fission neutrons, which are detected in a NE-213 liquid-scintillator detector, to be tagged. The resulting continuous polychromatic beam of tagged neutrons has an energy dependence that agrees qualitatively with expectations. We anticipate that this technique will provide a cost-effective means for the characterization of neutron-detector efficiency in the energy range 1-6 MeV.
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