| 1. |
- Croci, Gabriele, et al.
(författare)
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A high-efficiency thermal neutron detector based on thin 3D (B4C)-B-10 converters for high-rate applications
- 2018
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Ingår i: Europhysics letters. - : IOP Publishing. - 0295-5075 .- 1286-4854. ; 123:5
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Tidskriftsartikel (refereegranskat)abstract
- new position-sensitive thermal neutron detector based on boron-coated converters has been developed as an alternative to today's standard He-3-based technology for application to thermal neutron scattering. The key element of the development is a novel 3D (B4C)-B-10 converter which has been ad hoc designed and realized with the aim of combining a high neutron conversion probability via the B-10(n, alpha)(7) Li reaction together with an efficient collection of the produced charged particles. The developed 3D converter is composed of thin aluminium grids made by a micro-waterjet technique and coated on both sides with a thin layer of( 10)B(4)C. When coupled to a GEM detector this converter allows reaching neutron detection efficiencies close to 50% at neutron wavelengths equal to 4 angstrom. In addition, the new detector features a spatial resolution of about 5 min and can sustain counting rates well in excess of 1 MHz/cm(2). The newly developed neutron detector will enable time-resolved measurements of different kind of samples in neutron scattering experiments at high flux spallation sources and can find a use in applications where large areas and custom geometries of thermal neutron detectors are foreseen.
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| 2. |
- Croci, Gabriele, et al.
(författare)
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I-BAND-GEM : a new way for improving BAND-GEM efficiency to thermal and cold neutrons
- 2019
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Ingår i: The European Physical Journal Plus. - : Springer Science and Business Media LLC. - 2190-5444. ; 134:4
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Tidskriftsartikel (refereegranskat)abstract
- .The BAND-GEM detector represents one of the novel thermal neutron detection devices that have been developed in order to fulfil the needs of high intensity neutron sources that, like ESS (the European Spallation Source), will start operation in the next few years. The first version of this detector featured a detection efficiency of about 40% for neutrons with a wavelength of 4 angstrom, a spatial resolution of about 6mm and a rate capability in the order of some MHz/cm(2). The novelty of this device is represented by an improved 3D converter cathode (10 cm thick) based on (B4C)-B-10-coated aluminum grids positioned in a controlled gas mixture volume put on top of a Triple GEM amplifying stage. The position where the neutron interacts in the converter depends on their energy and it was observed that the first version of the detector would suffer from an efficiency decrease for long (>5 angstrom) neutron wavelength. This paper describes how the new 3D cathode allowed improving the detection efficiency at long neutron wavelengths while keeping all the benefits of the first BAND-GEM version.
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| 3. |
- Källne, Jan, et al.
(författare)
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Neutron Diagnostics For Mirror Hybrids
- 2012
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Ingår i: Fusion for Neutrons and Subcritical Nuclear Fission. - : AIP. - 9780735410381 ; , s. 281-288
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Konferensbidrag (refereegranskat)abstract
- Fusion-fission (FuFi) hybrids will need instrumentation to diagnose the deuterium-tritium plasma, whose 14-MeV neutron emission is the driver of the sub-critical fission core. While the fission neutron yield rate (Y-fi and hence power P-fi) can be monitored with standard instrumentation, fusion plasmas in hybrids require special diagnostics where the determination of Y-th (proportional to P-fu) is a challenge. Information on Y-fu is essential for assessing the fusion plasma performance which together with Y-fi allows for the validation of the neutron multiplication factor (k) of the subcritical fission core. Diagnostics for hybrid plasmas are heuristically discussed with special reference to straight field line mirror (SFLM). Relevant DT plasma experience from JET and plans for ITER in the main line of fusion research were used as input. It is shown that essential SFLM plasma information can potentially be obtained with proposed instrumentation, but the state of the hybrid plasma must be predictably robust as derived from fully diagnosed dedicated experiments without interface restrictions of the hybrid application.
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| 4. |
- Muraro, Andrea, et al.
(författare)
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Performance of the high-efficiency thermal neutron BAND-GEM detector
- 2018
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Ingår i: Progress of Theoretical and Experimental Physics. - : Oxford University Press (OUP). - 2050-3911. ; :2
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Tidskriftsartikel (refereegranskat)abstract
- Newhigh-count-rate detectors are required for future spallation neutron sources where large-area and high-efficiency (>50%) detectors are envisaged. In this framework, Gas Electron Multiplier (GEM) is one of the detector technologies being explored, since it features good spatial resolution (<0.5 cm) and timing properties, has excellent rate capability (MHz/mm(2)) and can cover large areas (some m(2)) at low cost. In the BAND-GEM (boron array neutron detector GEM) approach a 3D geometry for the neutron converter cathode was developed that is expected to provide an efficiency >30% in thewavelength range of interest for small angle neutron scattering instruments. A system of aluminum grids with thin walls coated with a 0.59 mu m layer of (B4C)-B-10 has been built and positioned in the first detector gap, orthogonally to the cathode. By tilting the grid system with respect to the beam, there is a significant increase of effective thickness of the borated material crossed by the neutrons. As a consequence, both interaction probability and detection efficiency are increased. This paper presents the results of the performance of the BAND-GEM detector in terms of efficiency and spatial resolution.
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