| 1. |
|
|
| 2. |
- Anastasopoulos, M., et al.
(författare)
-
Multi-Grid detector for neutron spectroscopy : Results obtained on time-of-flight spectrometer CNCS
- 2017
-
Ingår i: Journal of Instrumentation. - : IOP PUBLISHING LTD. - 1748-0221. ; 12:4
-
Tidskriftsartikel (refereegranskat)abstract
- The Multi-Grid detector technology has evolved from the proof-of-principle and characterisation stages. Here we report on the performance of the Multi-Grid detector, the MG.CNCS prototype, which has been installed and tested at the Cold Neutron Chopper Spectrometer, CNCS at SNS. This has allowed a side-by-side comparison to the performance of 3He detectors on an operational instrument. The demonstrator has an active area of 0.2 m2. It is specifically tailored to the specifications of CNCS. The detector was installed in June 2016 and has operated since then, collecting neutron scattering data in parallel to the He-3 detectors of CNCS. In this paper, we present a comprehensive analysis of this data, in particular on instrument energy resolution, rate capability, background and relative efficiency. Stability, gamma-ray and fast neutron sensitivity have also been investigated. The effect of scattering in the detector components has been measured and provides input to comparison for Monte Carlo simulations. All data is presented in comparison to that measured by the 3He detectors simultaneously, showing that all features recorded by one detector are also recorded by the other. The energy resolution matches closely. We find that the Multi-Grid is able to match the data collected by 3He, and see an indication of a considerable advantage in the count rate capability. Based on these results, we are confident that the Multi-Grid detector will be capable of producing high quality scientific data on chopper spectrometers utilising the unprecedented neutron flux of the ESS.
|
|
| 3. |
- Messi, F., et al.
(författare)
-
The neutron-tagging facility at Lund University
- 2020
-
Ingår i: Modern Neutron Detection : Proceedings of a Technical Meeting - Proceedings of a Technical Meeting. - 1011-4289. - 9789201265203 - 9789201266200 ; :1935, s. 287-297
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)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.
|
|
| 4. |
- Piscitelli, F., et al.
(författare)
-
The Multi-Blade Boron-10-based neutron detector for high intensity neutron reflectometry at ESS
- 2017
-
Ingår i: Journal of Instrumentation. - : IOP PUBLISHING LTD. - 1748-0221. ; 12:3
-
Tidskriftsartikel (refereegranskat)abstract
- The Multi-Blade is a Boron-10-based gaseous detector introduced to face the challenge arising in neutron reflectometry at pulsed neutron sources. Neutron reflectometers are the most challenging instruments in terms of instantaneous counting rate and spatial resolution. This detector has been designed to cope with the requirements set for the reflectometers at the upcoming European Spallation Source (ESS) in Sweden. Based on previous results obtained at the Institut Laue-Langevin (ILL) in France, an improved demonstrator has been built at ESS and tested at the Budapest Neutron Centre (BNC) in Hungary and at the Source Testing Facility (STF) at the Lund University in Sweden. A detailed description of the detector and the results of the tests are discussed in this manuscript.
|
|
| 5. |
- Birch, Jens, et al.
(författare)
-
In-beam test of the Boron-10 Multi-Grid neutron detector at the IN6 time-of-flight spectrometer at the ILL
- 2014
-
Ingår i: INTERNATIONAL WORKSHOP ON NEUTRON OPTICS AND DETECTORS (NOPandD 2013). - : IOP Publishing: Conference Series / Institute of Physics (IoP).
-
Konferensbidrag (refereegranskat)abstract
- A neutron detector concept based on solid layers of boron carbide enriched in 1 B has been in development for the last few years as an alternative for He-3 by collaboration between the ILL, ESS and Linkoping University. This Multi-Grid detector uses layers of aluminum substrates coated with (B4C)-B-10 on both sides that are traversed by the incoming neutrons. Detection is achieved using a gas counter readout principle. By segmenting the substrate and using multiple anode wires, the detector is made inherently position sensitive. This development is aimed primarily at neutron scattering instruments with large detector areas, such as time-of-flight chopper spectrometers. The most recent prototype has been built to be interchangeable with the He-3 detectors of IN6 at ILL. The 1 B detector has an active area of 32 x 48 cm(2). It was installed at the IN6 instrument and operated for several weeks, collecting data in parallel with the regularly scheduled experiments, thus providing the first side-by-side comparison with the conventional He-3 detectors. Results include an efficiency comparison, assessment of the in-detector scattering contribution, sensitivity to gamma-rays and the signal-to-noise ratio in time-of-flight spectra. The good expected performance has been confirmed with the exception of an unexpected background count rate. This has been identified as natural alpha activity in aluminum. New convertor substrates are under study to eliminate this source of background.
|
|
| 6. |
- Birch, J, et al.
(författare)
-
Investigation of background in large-area neutron detectors due to alpha emission from impurities in aluminium
- 2015
-
Ingår i: Journal of Instrumentation. - : IOP PUBLISHING LTD. - 1748-0221. ; 10
-
Tidskriftsartikel (refereegranskat)abstract
- Thermal neutron detector based on films of (B4C)-B-10 have been developed as an alternative to He-3 detectors. In particular, The Multi-Grid detector concept is considered for future large area detectors for ESS and ILL instruments. An excellent signal-to-background ratio is essential to attain expected scientific results. Aluminium is the most natural material for the mechanical structure of of the Multi-Grid detector and other similar concepts due to its mechanical and neutronic properties. Due to natural concentration of alpha emitters, however, the background from alpha particles misidentified as neutrons can be unacceptably high. We present our experience operating a detector prototype affected by this issue. Monte Carlo simulations have been used to confirm the background as alpha particles. The issues have been addressed in the more recent implementations of the Multi-Grid detector by the use of purified aluminium as well as Ni-plating of standard aluminium. The result is the reduction in background by two orders of magnitude. A new large-area prototype has been built incorporating these modifications.
|
|
| 7. |
- Birch, J., et al.
(författare)
-
Multi-Grid boron-10 detector for time-of-flight spectrometers in neutron scattering science
- 2015
-
Ingår i: 2015 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2015. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781467398626
-
Konferensbidrag (refereegranskat)abstract
- The Multi-Grid (MG) detector has been introduced at ILL and developed by a collaboration between ILL, ESS and Linkoping University. This detector design addresses the severely decreased availability of He3, in particular for neutron scattering instruments with large-area detectors, such as time-of-flight neutron spectrometers at ESS and other facilities. The MG detector is based on thin converter films of boron-10 carbide arranged in layers orthogonal to the incoming neutrons. The design of the detector provides position resolution, efficiency competitive with He3 and a strong gamma rejection capability. This paper presents the MG large-area (2.4m2) demonstrator and the progress made in order to meet the needs of production of B4C-coated layers, mechanical parts and assembly on a scale similar to that of the final detectors for ESS. A particular effort was made to produce aluminium detector parts with a low alpha background, successfully reducing the background rate to acceptable levels. Following the IN5 demonstrator, a compact prototype has been designed in order to finalise the electronic readout to be used at the ESS instruments equipped with the MG.
|
|
| 8. |
- Christensen, M. J., et al.
(författare)
-
Software-based data acquisition and processing for neutron detectors at European Spallation Source-early experience from four detector designs
- 2018
-
Ingår i: Journal of Instrumentation. - 1748-0221. ; 13:11
-
Tidskriftsartikel (refereegranskat)abstract
- European Spallation Source (ESS) will deliver neutrons at high flux for use in diverse neutron scattering techniques. The neutron source facility and the scientific instruments will be located in Lund, and the Data Management and Software Centre (DMSC), in Copenhagen. A number of detector prototypes are being developed at ESS together with its European in-kind partners, for example: SoNDe, Multi-Grid, Multi-Blade and Gd-GEM. These are all position sensitive detectors but use different techniques for the detection of neutrons. Except for digitization of electronics readout, all neutron data is anticipated to be processed in software. This provides maximum flexibility and adaptability and allows deep inspection of the raw data for commissioning which will reduce the risk of starting up new detector technologies. But it also requires development of high performance software processing pipelines and optimized and scalable processing algorithms. This report provides a description of the ESS system architecture for the neutron data path. Special focus is on the interface between the detectors and DMSC which is based on UDP over Ethernet links. The report also describes the software architecture for detector data processing and the tools we have developed, which have proven very useful for efficient early experimentation, and can be run on a single laptop. Processing requirements for the SoNDe, Multi-Grid, Multi-Blade and Ge-GEM detectors are presented and compared to event processing rates archived so far.
|
|
| 9. |
|
|
| 10. |
|
|
| 11. |
- Khaplanov, Anton, et al.
(författare)
-
Investigation of gamma-ray sensitivity of neutron detectors based on thin converter films
- 2013
-
Ingår i: Journal of Instrumentation. - 1748-0221. ; 8
-
Tidskriftsartikel (refereegranskat)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.
|
|
| 12. |
- Mauri, G., et al.
(författare)
-
Neutron reflectometry with the Multi-Blade B-10-based detector
- 2018
-
Ingår i: Proceedings of the Royal Society. Mathematical, Physical and Engineering Sciences. - : The Royal Society. - 1364-5021 .- 1471-2946. ; 474:2216
-
Tidskriftsartikel (refereegranskat)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.
|
|
| 13. |
- Mauri, G., et al.
(författare)
-
The Multi-Blade Boron-10-based neutron detector performance using a focusing reflectometer
- 2020
-
Ingår i: Journal of Instrumentation. - : IOP PUBLISHING LTD. - 1748-0221. ; 15:3
-
Tidskriftsartikel (refereegranskat)abstract
- The Multi-Blade is a Boron-10-based neutron detector designed for neutron reflectometers and developed for the two instruments (Estia and FREIA) planned for the European Spallation Source in Sweden. A demonstrator has been installed at the AMOR reflectometer at the Paul Scherrer Institut (PSI - Switzerland). AMOR exploits the Selene guide concept and can be considered a scaled-down demonstrator of Estia. The results of these tests are discussed. It will be shown how the characteristics of the Multi-Blade detector are features that allow the focusing reflectometry operation mode. Additionally the performance of the Multi-Blade, in terms of rate capability, exceeds current state-of-the-art technology. The improvements with respect to the previous prototypes are also highlighted; from background considerations to the linear and angular uniformity response of the detector.
|
|
| 14. |
- Messi, F., et al.
(författare)
-
Gamma- and Fast Neutron- Sensitivity of 10B- Based Neutron Detectors at ESS
- 2017
-
Ingår i: 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2017 - Conference Proceedings. - 9781538622827
-
Konferensbidrag (refereegranskat)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.
|
|
| 15. |
- Piscitelli, F., et al.
(författare)
-
Characterization of the Multi-Blade 10B-based detector at the CRISP reflectometer at ISIS for neutron reflectometry at ESS
- 2018
-
Ingår i: Journal of Instrumentation. - : IOP PUBLISHING LTD. - 1748-0221. ; 13:5
-
Tidskriftsartikel (refereegranskat)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.
|
|
| 16. |
- Piscitelli, F., et al.
(författare)
-
Study of a high spatial resolution B-10-based thermal neutron detector for application in neutron reflectometry: the Multi-Blade prototype
- 2014
-
Ingår i: Journal of Instrumentation. - 1748-0221. ; 9
-
Tidskriftsartikel (refereegranskat)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.
|
|
| 17. |
|
|
| 18. |
- Andersen, Ken, et al.
(författare)
-
B-10 multi-grid proportional gas counters for large area thermal neutron detectors
- 2013
-
Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0167-5087 .- 0168-9002 .- 1872-9576. ; 720, s. 116-121
-
Tidskriftsartikel (refereegranskat)abstract
- He-3 was a popular material in neutrons detectors until its availability dropped drastically in 2008. The development of techniques based on alternative convertors is now of high priority for neutron research institutes. Thin films of B-10 or (B4C)-B-10 have been used in gas proportional counters to detect neutrons, but until now, only for small or medium sensitive area. We present here the multi-grid design, introduced at the ILL and developed in collaboration with ESS for LAN (large area neutron) detectors. Typically thirty (B4C)-B-10 films of 1 mu m thickness are used to convert neutrons into ionizing particles which are subsequently detected in a proportional gas counter. The principle and the fabrication of the multi-grid are described and some preliminary results obtained with a prototype of 200 cm x 8 cm are reported; a detection efficiency of 48% has been measured at 2.5 angstrom with a monochromatic neutron beam line, showing the good potential of this new technique. (C) 2013 Elsevier B.V. All rights reserved.
|
|
| 19. |
- Birch, Jens, et al.
(författare)
-
(B4C)-B-10 Multi-Grid as an Alternative to He-3 for Large Area Neutron Detectors
- 2013
-
Ingår i: IEEE Transactions on Nuclear Science. - 0018-9499 .- 1558-1578. ; 60:2, s. 871-878
-
Tidskriftsartikel (refereegranskat)abstract
- Despite its present shortage, He-3 continues to be the most common neutron converter for detectors in neutron scattering science. However, it is obvious that the development of large area neutron detectors based on alternative neutron converters is rapidly becoming a matter of urgency. In the technique presented here, grids each comprising 28 (B4C)-B-10 layers ( each 1 mu m thick) are used to convert neutrons into ionizing particles which are subsequently detected in proportional gas counters. The total active area of the prototype is 8 cm x 200 cm. To instrument this detector 4.6 m(2) of B-10-enriched boron carbide were coated onto aluminium blades using a DC magnetron sputtering machine. Characterization of the prototype showed neutron efficiency to be epsilon(n) = 46.8% for 2.5 angstrom neutrons, which is in line with expectations from MC simulation. This result demonstrates the potential of this technique as alternative to He-3-based position sensitive detectors.
|
|
| 20. |
- Galgoczi, G., et al.
(författare)
-
Investigation of neutron scattering in the Multi-Blade detector with Geant4 simulations
- 2018
-
Ingår i: Journal of Instrumentation. - 1748-0221. ; 13
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
|
|
| 21. |
- Kanaki, K., et al.
(författare)
-
An alternative small angle neutron scattering detector
- 2013
-
Ingår i: IEEE Nuclear Science Symposium Conference Record. - : IEEE conference proceedings. - 9781479905348 ; , s. Art. no. 6829478-
-
Konferensbidrag (refereegranskat)abstract
- An alternative detector design for Small Angle Neutron Scattering (SANS) applications is currently under development at the European Spallation Source (ESS). Given the unavailability and high price of 3He, this detector design utilizes gaseous detectors with 10B as neutron converter and is ideally suited for a SANS instrument at the ESS. The novel aspects of the geometry, exploiting the properties of the converting material, in combination with the performance of the detector are addressed by means of analytical calculations, as well as detailed Monte Carlo simulations using a customized version of Geant4. Last but not least, the progress on the conceptual prototype design is presented. © 2013 IEEE.
|
|
| 22. |
- Khaplanov, A., et al.
(författare)
-
Neutron beam monitors for the European spallation source
- 2015
-
Ingår i: 2015 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2015. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781467398626
-
Konferensbidrag (refereegranskat)abstract
- The European Spallation Source (ESS), currently under construction in Lund, Sweden, will house a suite of 16 user instruments for neutron scattering experiments. The spallation source of the ESS will emit relatively long, 2.8 ms, neutron pulses with an integrated flux that will greatly exceed that of current facilities. This leads to both large advancements in instrument performance as well as to increased length and complexity of the beam delivery systems. The instruments will each be equipped with neutron beam monitors used for data normalisation and analysis, as well as commissioning and diagnostics. In this paper we present the requirements for beam monitors for the ESS and the strategy to meet these in a standardised approach. A large range of specifications in efficiency, dynamic range, time and position resolution, compatible materials are needed. A new feature for neutron beam monitors for some locations, is the ability to measure time profile of each source pulse individually. In general, event mode readout will be used for monitors, similarly to other neutron detectors at the facility. A selection of detectors based on different technologies will be available. Monitors will be integrated with beam lines and choppers in a way that allows to freely choose the type of monitor based on final requirements of an instrument. For this end, space for a standardised module, housing a monitor will be provided in conjunction with chopper assemblies and elsewhere on each beam line.
|
|
| 23. |
- Kirstein, Oliver, et al.
(författare)
-
Neutron position sensitive detectors for the ESS
- 2014
-
Ingår i: Proceedings of Science. - : Proceedings of Science (PoS). ; Vertex2014, s. 029-029
-
Konferensbidrag (refereegranskat)abstract
- The European Spallation Source (ESS) in Lund, Sweden will become the world's leading neutron source for the study of materials. It will be a long pulse source, with an average beam power of 5 MW delivered to the target station. The ESS is in the construction phase, which started in 2013 with the completion of the Technical Design Report (TDR). The instruments are being selected from conceptual proposals submitted by groups from around Europe. These instruments present numerous challenges for detector technology in the absence of the availability of Helium-3, which is the default choice for detectors for instruments built until today and due to the extreme rates expected across the ESS instrument suite. Additionally a new generation of source requires a new generation of detector technologies to fully exploit the opportunities that this source provides. To meet this challenge at a green-field site, the detectors will be sourced from partners across Europe through numerous in-kind arrangements; a process that is somewhat novel for the neutron scattering community. This contribution presents briefly the current status of detectors for the ESS, and outlines the timeline to completion. For a conjectured instrument suite based upon instruments recommended for construction, a recently updated snapshot of the current expected detector requirements is presented. A strategy outline as to how these requirements might be tackled by novel detector developments is shown. In terms of future developments for the neutron community, synergies should be sought with other disciples, as recognized by various recent initiatives in Europe, in the context of the fundamentally multi-disciplinary nature of detectors. This strategy has at its basis the in-kind and collaborative partnerships necessary to be able to produce optimally performant detectors that allow the ESS instruments to be world-leading. This foresees and encourages a high level of collaboration and interdependence at its core, and rather than each group being all-rounders in every technology, the further development of centres of excellence across Europe for particular technologies and niches.
|
|
| 24. |
|
|
