| 11. |
- Khaplanov, Anton, et al.
(author)
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Investigation of gamma-ray sensitivity of neutron detectors based on thin converter films
- 2013
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In: Journal of Instrumentation. - 1748-0221. ; 8
-
Journal article (peer-reviewed)abstract
- Currently, many detector technologies for thermal neutron detection are in development in order to lower the demand for the rare He-3 gas. Gas detectors with solid thin film neutron converters readout by gas proportional counter method have been proposed as an appropriate choice for applications where large area coverage is necessary. In this paper, we investigate the probability for gamma-rays to generate a false count in a neutron measurement. Simulated results are compared to measurement with B-10 thin film prototypes and a He-3 detector. It is demonstrated that equal gamma-ray rejection to that of He-3 tubes is achieved with the new technology. The arguments and results presented here are also applicable to gas detectors with converters other than solid B-10 layers, such as Li-6 layers and (BF3)-B-10 gas.
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| 12. |
- Mauri, G., et al.
(author)
-
Neutron reflectometry with the Multi-Blade B-10-based detector
- 2018
-
In: Proceedings of the Royal Society. Mathematical, Physical and Engineering Sciences. - : The Royal Society. - 1364-5021 .- 1471-2946. ; 474:2216
-
Journal article (peer-reviewed)abstract
- The Multi-Blade is a boron-10-based gaseous detector developed for neutron reflectometry instruments at the European Spallation Source in Sweden. The main challenges for neutron reflectometry detectors are the instantaneous counting rate and spatial resolution. The Multi-Blade has been tested on the CRISP reflectometer at the ISIS Neutron and Muon Source in the UK. A campaign of scientific measurements has been performed to study the Multi-Blade response in real instrumental conditions. The results of these tests are discussed in this paper.
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| 13. |
- Messi, F., et al.
(author)
-
Gamma- and Fast Neutron- Sensitivity of 10B- Based Neutron Detectors at ESS
- 2017
-
In: 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2017 - Conference Proceedings. - 9781538622827
-
Conference paper (peer-reviewed)abstract
- The European Spallation Source (ESS), presently under construction in Lund, Sweden, is designed to be the world's brightest neutron source. When it will be in operation, ESS will deliver an instantaneous neutron flux on detectors that will be without precedent. A down side of the high brightness will be the increase of background, especially from gamma-rays and fast-neutrons.Considering that scattering cross-sections of many samples tend to be relatively low and that the gamma- and fast-neutronbackgrounds tend to be considerable high at spallation facilities [Che +14], the signal-to-noise ratio of a measurement needs to be maximised. The sensitivity of a thermal-neutron detector to gamma-rays and to fast-neutrons is a very important characteristic, as it defines the best achievable signal-to-noise ratio for the measurement. It is therefore crucial to measure the gamma- and fast-neutron- sensitivities of all detectors that will be installed on the instruments at ESS.
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| 14. |
- Messi, F., et al.
(author)
-
The neutron-tagging facility at Lund University
- 2020
-
In: Modern Neutron Detection : Proceedings of a Technical Meeting - Proceedings of a Technical Meeting. - 1011-4289. - 9789201265203 - 9789201266200 ; :1935, s. 287-297
-
Conference paper (other academic/artistic)abstract
- Over the last decades, the field of thermal neutron detection has overwhelmingly employed He-3-based technologies. The He-3 crisis together with the forthcoming establishment of the European Spallation Source have necessitated the development of new technologies for neutron detection. Today, several promising He-3-free candidates are under detailed study and need to be validated. This validation process is in general long and expensive. The study of detector prototypes using neutron-emitting radioactive sources is a cost-effective solution, especially for preliminary investigations. That said, neutron-emitting sources have the general disadvantage of broad, structured, emitted-neutron energy ranges. Further, the emitted neutrons often compete with unwanted backgrounds of gamma-rays, alpha-particles, and fission-fragments. By blending experimental infrastructure such as shielding to provide particle beams with neutron-detection techniques such as tagging, disadvantages may be converted into advantages. In particular, a technique known as tagging involves exploiting the mixed-field generally associated with a neutron-emitting source to determine neutron time-of-flight and thus energy on an event-by-event basis. This allows for the definition of low-cost, precision neutron beams. The Source-Testing Facility, located at Lund University in Sweden and operated by the SONNIG Group of the Division of Nuclear Physics, was developed for just such low-cost studies. Precision tagged-neutron beams derived from radioactive sources are available around-the-clock for advanced detector diagnostic studies. Neutron measurements performed at the Source Testing Facility are thus cost-effective and have a very low barrier for entry. In this paper, we present an overview of the project.
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| 15. |
- Piscitelli, F., et al.
(author)
-
Characterization of the Multi-Blade 10B-based detector at the CRISP reflectometer at ISIS for neutron reflectometry at ESS
- 2018
-
In: Journal of Instrumentation. - : IOP PUBLISHING LTD. - 1748-0221. ; 13:5
-
Journal article (peer-reviewed)abstract
- 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.
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| 16. |
- Piscitelli, Francesco, et al.
(author)
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Neutron reflectometry on highly absorbing films and its application to (B4C)-B-10-based neutron detectors
- 2016
-
In: Royal Society of London. Proceedings A. Mathematical, Physical and Engineering Sciences. - : The Royal Society. - 1364-5021 .- 1471-2946. ; 472:2185
-
Journal article (peer-reviewed)abstract
- Neutron reflectometry is a powerful tool used for studies of surfaces and interfaces. The absorption in the typical studied materials is neglected and this technique is limited only to the reflectivity measurement. For strongly absorbing nuclei, the absorption can be directly measured by using the neutron-induced fluorescence technique which exploits the prompt particle emission of absorbing isotopes. This technique is emerging from soft matter and biology where highly absorbing nuclei, in very small quantities, are used as a label for buried layers. Nowadays, the importance of absorbing layers is rapidly increasing, partially because of their application in neutron detection; a field that has become more active also due to the He-3-shortage. We extend the neutron-induced fluorescence technique to the study of layers of highly absorbing materials, in particular (B4C)-B-10. The theory of neutron reflectometry is a commonly studied topic; however, when a strong absorption is present the subtle relationship between the reflection and the absorption of neutrons is not widely known. The theory for a general stack of absorbing layers has been developed and compared to measurements. We also report on the requirements that a (B4C)-B-10 layer must fulfil in order to be employed as a converter in neutron detection.
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| 17. |
- Piscitelli, F., et al.
(author)
-
Study of a high spatial resolution B-10-based thermal neutron detector for application in neutron reflectometry: the Multi-Blade prototype
- 2014
-
In: Journal of Instrumentation. - 1748-0221. ; 9
-
Journal article (peer-reviewed)abstract
- Although for large area detectors it is crucial to find an alternative to detect thermal neutrons because of the He-3 shortage, this is not the case for small area detectors. Neutron scattering science is still growing its instruments' power and the neutron flux a detector must tolerate is increasing. For small area detectors the main effort is to expand the detectors' performances. At Institut Laue-Langevin (ILL) we developed the Multi-Blade detector which wants to increase the spatial resolution of He-3-based detectors for high flux applications. We developed a high spatial resolution prototype suitable for neutron reflectometry instruments. It exploits solid B-10-films employed in a proportional gas chamber. Two prototypes have been constructed at ILL and the results obtained on our monochromatic test beam line are presented here.
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| 18. |
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| 19. |
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