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Hall-Wilton, RichardORCID iD iconorcid.org/0000-0003-3221-2086
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Publications (10 of 49) Show all publications
Margato, L. M., Morozov, A., Blanco, A., Fonte, P., Fraga, F. A., Guerard, B., . . . Zeitelhack, K. (2019). Boron-10 lined RPCs for sub-millimeter resolution thermal neutron detectors: Feasibility study in a thermal neutron beam. Journal of Instrumentation, 14(1), Article ID P01017.
Open this publication in new window or tab >>Boron-10 lined RPCs for sub-millimeter resolution thermal neutron detectors: Feasibility study in a thermal neutron beam
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2019 (English)In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 14, no 1, article id P01017Article in journal (Refereed) Published
Abstract [en]

The results of an experimental feasibility study of a position sensitive thermal neutron detector based on a resistive plate chamber (RPC) are presented. The detector prototype features a thin-gap (0.35 mm) hybrid RPC with an aluminium cathode and a float glass anode. The cathode is lined with a 2 mu m thick (B4C)-B-10 neutron converter enriched in B-10. A detection efficiency of 6.2% is measured at the neutron beam (lambda = 2.5 angstrom) for normal incidence. A spatial resolution better than 0.5 mm FWHM is demonstrated.

Keywords
Neutron detectors (cold, thermal, fast neutrons), Resistive-plate chambers, Gaseous detectors
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:miun:diva-35800 (URN)10.1088/1748-0221/14/01/P01017 (DOI)000455951500003 ()2-s2.0-85062518168 (Scopus ID)
Available from: 2019-03-18 Created: 2019-03-18 Last updated: 2019-03-25Bibliographically approved
Croci, G., Muraro, A., Cippo, E. P., Grosso, G., Hoglund, C., Hall-Wilton, R., . . . Gorini, G. (2019). I-BAND-GEM: a new way for improving BAND-GEM efficiency to thermal and cold neutrons. The European Physical Journal Plus, 134(4), Article ID 166.
Open this publication in new window or tab >>I-BAND-GEM: a new way for improving BAND-GEM efficiency to thermal and cold neutrons
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2019 (English)In: The European Physical Journal Plus, ISSN 2190-5444, E-ISSN 2190-5444, Vol. 134, no 4, article id 166Article in journal (Refereed) Published
Abstract [en]

.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.

Identifiers
urn:nbn:se:miun:diva-36195 (URN)10.1140/epjp/i2019-12522-5 (DOI)000465641900001 ()2-s2.0-85064921396 (Scopus ID)
Available from: 2019-05-22 Created: 2019-05-22 Last updated: 2019-07-08Bibliographically approved
Vitucci, G., Minniti, T., Angella, G., Croci, G., Muraro, A., Hoglund, C., . . . Gorini, G. (2019). Measurement of the thickness of B4C layers deposited over metallic grids via multi-angle neutron radiography. Measurement science and technology, 30(1), Article ID 015402.
Open this publication in new window or tab >>Measurement of the thickness of B4C layers deposited over metallic grids via multi-angle neutron radiography
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2019 (English)In: Measurement science and technology, ISSN 0957-0233, E-ISSN 1361-6501, Vol. 30, no 1, article id 015402Article in journal (Refereed) Published
Abstract [en]

At the present time, different kinds of thermal neutron detectors are under development at the European Spallation Source research facility, in order to overcome the well-known problem of the He-3 shortage. One of these new systems relies on the use of a 3D neutron convener cathode that consists of a stack of aluminum grids, covered by a 0.9 mu m B-10 enriched boron carbide layer ((B4C)-B-10). As the conversion efficiency is a function of the boron thickness and the mean free path of the charged particles produced in the neutron induced reaction, the characterization of the boron carbide layer uniformity over the grids becomes crucial. In this work, a non-destructive method to map the thickness distribution of the converter layer over the grids is shown. The measurements exploit the white-beam neutron radiography technique where the specimen is irradiated at different angles. This experiment has been performed at the IMAT beamline operating at the ISIS spallation neutron source (UK). The results confirm that this non-destructive, wide-ranging technique allows a reliable and fast sample characterization and that it may be exploited in similar analyses where equivalent requirements are requested.

Keywords
neutron radiography, non-destructive analysis, thickness measurement
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:miun:diva-35405 (URN)10.1088/1361-6501/aaf409 (DOI)000453373700001 ()2-s2.0-85063965616 (Scopus ID)
Available from: 2019-01-08 Created: 2019-01-08 Last updated: 2019-05-24Bibliographically approved
Rofors, E., Perrey, H., Al Jebali, R., Armand, J. R., Boyd, L., Clemens, U., . . . Seitz, B. (2019). Response of a Li-glass/multi-anode photomultiplier detector to alpha-particles from Am-241. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 929, 90-96
Open this publication in new window or tab >>Response of a Li-glass/multi-anode photomultiplier detector to alpha-particles from Am-241
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2019 (English)In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 929, p. 90-96Article in journal (Refereed) Published
Abstract [en]

The response of a position-sensitive Li-glass scintillator detector to alpha-particles from a collimated Am-241 source scanned across the face of the detector has been measured. Scintillation light was read out by an 8 x 8 pixel multi-anode photomultiplier and the signal amplitude for each pixel has been recorded for every position on a scan. The pixel signal is strongly dependent on position and in general several pixels will register a signal (a hit) above a given threshold. The effect of this threshold on hit multiplicity is studied, with a view to optimize the single-hit efficiency of the detector.

Keywords
SoNDe thermal neutron detector; GS20 scintillating glass, Multi-anode photomultiplier, Position-dependent alpha-particle response, H12700A
Identifiers
urn:nbn:se:miun:diva-36182 (URN)10.1016/j.nima.2019.03.014 (DOI)000464347000011 ()2-s2.0-85063412874 (Scopus ID)
Available from: 2019-05-22 Created: 2019-05-22 Last updated: 2019-05-24Bibliographically approved
Dian, E., Kanaki, K., Khaplanov, A., Kittelmann, T., Zagyvai, P. & Hall-Wilton, R. (2019). Suppression of intrinsic neutron background in the Multi-Grid detector. Journal of Instrumentation, 14, Article ID P01021.
Open this publication in new window or tab >>Suppression of intrinsic neutron background in the Multi-Grid detector
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2019 (English)In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 14, article id P01021Article in journal (Refereed) Published
Abstract [en]

One of the key requirements for neutron scattering instruments is the Signal-toBackground ratio (SBR). This is as well a design driving requirement for many instruments at the European Spallation Source (ESS), which aspires to be the brightest neutron source of the world. The SBR can be effectively improved with background reduction. The Multi-Grid, a large-area thermal neutron detector with a solid boron carbide converter, is a novel solution for chopper spectrometers. This detector will be installed for the three prospective chopper spectrometers at the ESS. As the Multi-Grid detector is a large area detector with a complex structure, its intrinsic background and its suppression via advanced shielding design should be investigated in its complexity, as it cannot be naively calculated. The intrinsic scattered neutron background and its effect on the SBR is determined via a detailed Monte Carlo simulation for the Multi-Grid detector module, designed for the CSPEC instrument at the ESS. The impact of the detector vessel and the neutron entrance window on scattering is determined, revealing the importance of an optimised internal detector shielding. The background-reducing capacity of common shielding geometries, like side-shielding and end-shielding is determined by using perfect absorber as shielding material, and common shielding materials, like B4C and Cd are also tested. On the basis of the comparison of the effectiveness of the different shielding topologies and materials, recommendations are given for a combined shielding of the Multi-Grid detector module, optimised for increased SBR.

Keywords
Detector modelling and simulations I (interaction of radiation with matter, interaction of photons with matter, interaction of hadrons with matter, etc), Neutron detectors (cold, thermal, fast neutrons), Gaseous detectors
Identifiers
urn:nbn:se:miun:diva-35660 (URN)10.1088/1748-0221/14/01/P01021 (DOI)000456238500003 ()2-s2.0-85062598744 (Scopus ID)
Available from: 2019-02-15 Created: 2019-02-15 Last updated: 2019-03-25Bibliographically approved
Croci, G., Muraro, A., Cippo, E. P., Tardocchi, M., Grosso, G., Albani, G., . . . Gorini, G. (2018). A high-efficiency thermal neutron detector based on thin 3D (B4C)-B-10 converters for high-rate applications. Europhysics letters, 123(5), Article ID 52001.
Open this publication in new window or tab >>A high-efficiency thermal neutron detector based on thin 3D (B4C)-B-10 converters for high-rate applications
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2018 (English)In: Europhysics letters, ISSN 0295-5075, E-ISSN 1286-4854, Vol. 123, no 5, article id 52001Article in journal (Refereed) Published
Abstract [en]

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. 

National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:miun:diva-34888 (URN)10.1209/0295-5075/123/52001 (DOI)000446207300001 ()2-s2.0-85054626431 (Scopus ID)
Available from: 2018-11-15 Created: 2018-11-15 Last updated: 2018-12-06Bibliographically approved
Piscitelli, F., Mauri, G., Messi, F., Anastasopoulos, M., Arnold, T., Glavic, A., . . . Hall-Wilton, R. (2018). Characterization of the Multi-Blade 10B-based detector at the CRISP reflectometer at ISIS for neutron reflectometry at ESS. Journal of Instrumentation, 13(5), Article ID P05009.
Open this publication in new window or tab >>Characterization of the Multi-Blade 10B-based detector at the CRISP reflectometer at ISIS for neutron reflectometry at ESS
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2018 (English)In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 13, no 5, article id P05009Article in journal (Refereed) Published
Abstract [en]

The Multi-Blade is a Boron-10-based gaseous thermal neutron detector developed to face the challenge arising in neutron reflectometry at neutron sources. Neutron reflectometers are challenging instruments in terms of instantaneous counting rate and spatial resolution. This detector has been designed according to the requirements given by the reflectometers at the European Spallation Source (ESS) in Sweden. The Multi-Blade has been installed and tested on the CRISP reflectometer at the ISIS neutron and muon source in U.K.. The results on the detailed detector characterization are discussed in this manuscript.

Keywords
Gaseous detectors, Neutron detectors (cold, thermal, fast neutrons)
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:miun:diva-33679 (URN)10.1088/1748-0221/13/05/P05009 (DOI)000431716900003 ()2-s2.0-85048078275 (Scopus ID)
Available from: 2018-05-30 Created: 2018-05-30 Last updated: 2018-09-27Bibliographically approved
Kanaki, K., Klausz, M., Kittelmann, T., Albani, G., Cippo, E. P., Jackson, A., . . . Hall-Wilton, R. (2018). Detector rates for the Small Angle Neutron Scattering instruments at the European Spallation Source. Journal of Instrumentation, 13, Article ID P07016.
Open this publication in new window or tab >>Detector rates for the Small Angle Neutron Scattering instruments at the European Spallation Source
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2018 (English)In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 13, article id P07016Article in journal (Refereed) Published
Abstract [en]

Building the European Spallation Source (ESS), the most powerful neutron source in the world, requires significant technological advances at most fronts of instrument component design. Detectors are not an exception. The existing implementations at current neutron scattering facilities are at their performance limits and sometimes barely cover the scientific needs. At full operation the ESS will yield unprecedented neutron brilliance. This means that one of the most challenging aspects for the new detector designs is the increased rate capability and in particular the peak instantaneous rate capability, i.e. the number of neutrons hitting the detector per channel, pixel or cm(2) at the peak of the neutron pulse. This paper focuses on estimating the incident and detection rates that are anticipated for the Small Angle Neutron Scattering (SANS) instruments planned for ESS. Various approaches are applied and the results thereof are presented.

National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:miun:diva-34226 (URN)10.1088/1748-0221/13/07/P07016 (DOI)000439306700002 ()2-s2.0-85051529374 (Scopus ID)
Available from: 2018-08-13 Created: 2018-08-13 Last updated: 2018-10-01Bibliographically approved
Mauri, G., Messi, F., Kanaki, K., Hall-Wilton, R., Karnickis, E., Khaplanov, A. & Piscitelli, F. (2018). Fast neutron sensitivity of neutron detectors based on Boron-10 converter layers. Journal of Instrumentation, 13(3), Article ID P03004.
Open this publication in new window or tab >>Fast neutron sensitivity of neutron detectors based on Boron-10 converter layers
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2018 (English)In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 13, no 3, article id P03004Article in journal (Refereed) Published
Abstract [en]

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.

Keywords
Gaseous detectors, Neutron detectors (cold, thermal, fast neutrons), Wire chambers (MWPC, Thin-gap chambers, drift chambers, drift tubes, proportional chambers etc)
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:miun:diva-33396 (URN)10.1088/1748-0221/13/03/P03004 (DOI)000427007300004 ()2-s2.0-85044992503 (Scopus ID)
Available from: 2018-04-03 Created: 2018-04-03 Last updated: 2018-07-19Bibliographically approved
Galgoczi, G., Kanaki, K., Piscitelli, F., Kittelmann, T., Varga, D. & Hall-Wilton, R. (2018). Investigation of neutron scattering in the Multi-Blade detector with Geant4 simulations. Journal of Instrumentation, 13, Article ID P12031.
Open this publication in new window or tab >>Investigation of neutron scattering in the Multi-Blade detector with Geant4 simulations
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2018 (English)In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 13, article id P12031Article in journal (Refereed) Published
Abstract [en]

The European Spallation Source (ESS) is the world's next generation spallation-based neutron source. The research conducted at ESS will yield in the discovery and development of new materials including the fields of manufacturing, pharmaceuticals, aerospace, engines, plastics, energy, telecommunications, transportation, information technology and biotechnology. The spallation source will deliver an unprecedented neutron flux. In particular, the reflectometers selected for construction, ESTIA and FREIA, have to fulfill challenging requirements. Local incident peak rate can reach 10(5) Hz/mm(2). For new science to be addressed, the spatial resolution is aimed to be less than 1 mm with a desired scattering of 10(-4) (peak-to-tail ratio). The latter requirement is approximately two orders of magnitude better than the current state-of-the-art detectors. The main aim of this work is to quantify the cumulative contribution of various detector components to the scattering of neutrons and to prove that the respective effect is within the requirements set for the Multi-Blade detector by the ESS reflectometers. To this end, different sets of geometry and beam parameters are investigated, with primary focus on the cathode coating and the detector window thickness.

Keywords
Detector modelling and simulations I (interaction of radiation with matter, interaction of photons with matter, interaction of hadrons with matter, etc), Neutron detectors (cold, thermal, fast neutrons), Gaseous detectors
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:miun:diva-35403 (URN)10.1088/1748-0221/13/12/P12031 (DOI)000453890700004 ()2-s2.0-85059907499 (Scopus ID)
Available from: 2019-01-08 Created: 2019-01-08 Last updated: 2019-08-06Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0003-3221-2086

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