The extensive heat release in the target is the primary limiting factor for a CANS neutron output. CANS DARIA has been chosen to operate using a 13 MeV proton beam providing up to 40 kW of power, which requires an effective target cooling solution. It was found that beryllium provides the best neutron yield while staying in solid state, which makes it the most effective option for the target material. With an optimal beryllium target thickness of 1.1 mm, the proton Bragg peak lies outside of the beryllium layer, but 9.21 MeV per incident proton are still dissipated inside the beryllium. Two cooling options are considered and analysed with PHITS calculations: multilayer targets and rotating targets. The use of proton beams with energies above 13 MeV on beryllium leads to tritium generation, which is not desirable. Any lower energy leads to a decreased neutron yield, but a simpler cooling solution. Therefore, an option to reduce the proton beam energy is also considered.
{"title":"Target cooling options for DARIA compact neutron source","authors":"A. R. Moroz, N. Kovalenko, S. Grigoriev","doi":"10.3233/jnr-220025","DOIUrl":"https://doi.org/10.3233/jnr-220025","url":null,"abstract":"The extensive heat release in the target is the primary limiting factor for a CANS neutron output. CANS DARIA has been chosen to operate using a 13 MeV proton beam providing up to 40 kW of power, which requires an effective target cooling solution. It was found that beryllium provides the best neutron yield while staying in solid state, which makes it the most effective option for the target material. With an optimal beryllium target thickness of 1.1 mm, the proton Bragg peak lies outside of the beryllium layer, but 9.21 MeV per incident proton are still dissipated inside the beryllium. Two cooling options are considered and analysed with PHITS calculations: multilayer targets and rotating targets. The use of proton beams with energies above 13 MeV on beryllium leads to tritium generation, which is not desirable. Any lower energy leads to a decreased neutron yield, but a simpler cooling solution. Therefore, an option to reduce the proton beam energy is also considered.","PeriodicalId":44708,"journal":{"name":"Journal of Neutron Research","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42306600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Taketani, Takaoki Takanashi, C. Iwamoto, Tomohiro Kobayashi, Masato Takamura
A sample-motion-synchronized neutron stroboscope is developed using the RIKEN accelerator-based compact neutron source (RANS). When a sample reaches a specified rotation phase, a phase timing signal is generated, triggering a proton pulse at the proton accelerator. A neutron pulse exposes the imaging detector through the sample. By controlling the delay time between the phase signal and the proton pulse timing, the neutron exposure timing is always synchronized with the specific sample rotation phase. A sample rotating at a speed of 1800 RPM is prepared, and clear still images of neutrons are taken.
{"title":"Sample-motion-synchronized neutron stroboscope at RANS","authors":"A. Taketani, Takaoki Takanashi, C. Iwamoto, Tomohiro Kobayashi, Masato Takamura","doi":"10.3233/jnr-220035","DOIUrl":"https://doi.org/10.3233/jnr-220035","url":null,"abstract":"A sample-motion-synchronized neutron stroboscope is developed using the RIKEN accelerator-based compact neutron source (RANS). When a sample reaches a specified rotation phase, a phase timing signal is generated, triggering a proton pulse at the proton accelerator. A neutron pulse exposes the imaging detector through the sample. By controlling the delay time between the phase signal and the proton pulse timing, the neutron exposure timing is always synchronized with the specific sample rotation phase. A sample rotating at a speed of 1800 RPM is prepared, and clear still images of neutrons are taken.","PeriodicalId":44708,"journal":{"name":"Journal of Neutron Research","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48135448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The ESS ERIC neutron source design includes a helium cooled tungsten spallation target and a liquid hydrogen moderator, enclosed in a vacuum vessel (the monolith vessel – spallation source vacuum chamber). The neutron source and moderator are shielded by stainless steel and casted iron to block neutron and gamma radiation emitted in directions outside of the neutron guide lines. After the ESS concept design was approved, discussions were raised if it was possible to introduce a UCN/VCN (Ultra Cold Neutron / Very Cold Neutron) source into the ESS design. Since the shielding concept of the monolith vessel is to 100% fill the monolith void, outside of the proton and neutron path, there are no cavities in the monolith vessel to easily introduce an UCN/VCN source. In addition, pipe routing supporting the UCN/VCN cooling media, will also challenge the possible UCN/VCN positions. However, some of the shielding blocks and monolith components are removable and could possibly be redesigned, enabling a UCN/VCN source feature. The article presents a feasibility study how to physically introduce a UCN/VCN source in the present ESS design, and focus on the geometrical possibilities. Four possible locations for the UCN/VCN source are identified and presented in the article. The locations are selected considered reasonable impact to the existing design. Pros and cons are discussed. All of the four presented locations are feasible but will, to some extent, require redesign of the monolith vessel shielding.
{"title":"The ESS Monolith Vessel design and possibilities to introduce a UCN/VCN source","authors":"U. Odén","doi":"10.3233/jnr-220014","DOIUrl":"https://doi.org/10.3233/jnr-220014","url":null,"abstract":"The ESS ERIC neutron source design includes a helium cooled tungsten spallation target and a liquid hydrogen moderator, enclosed in a vacuum vessel (the monolith vessel – spallation source vacuum chamber). The neutron source and moderator are shielded by stainless steel and casted iron to block neutron and gamma radiation emitted in directions outside of the neutron guide lines. After the ESS concept design was approved, discussions were raised if it was possible to introduce a UCN/VCN (Ultra Cold Neutron / Very Cold Neutron) source into the ESS design. Since the shielding concept of the monolith vessel is to 100% fill the monolith void, outside of the proton and neutron path, there are no cavities in the monolith vessel to easily introduce an UCN/VCN source. In addition, pipe routing supporting the UCN/VCN cooling media, will also challenge the possible UCN/VCN positions. However, some of the shielding blocks and monolith components are removable and could possibly be redesigned, enabling a UCN/VCN source feature. The article presents a feasibility study how to physically introduce a UCN/VCN source in the present ESS design, and focus on the geometrical possibilities. Four possible locations for the UCN/VCN source are identified and presented in the article. The locations are selected considered reasonable impact to the existing design. Pros and cons are discussed. All of the four presented locations are feasible but will, to some extent, require redesign of the monolith vessel shielding.","PeriodicalId":44708,"journal":{"name":"Journal of Neutron Research","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44199419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This article reviews the development of various sources for ultracold neutrons (UCNs) at the Petersburg Nuclear Physics Institute (PNPI). For 45 years, PNPI has proposed and manufactured cryogenic devices for neutron conversion to low energies. Based on beryllium, hydrogen and deuterium, they can be operated in the intense radiation fields near the core of a nuclear reactor. A more recently launched UCN source development utilizes superfluid helium (He-II) as conversion medium. Initially proposed and designed for PNPI’s old WWR-M reactor, the project has been reshaped to equip the institute’s PIK reactor with a modern UCN source of this type. The projected UCN density in the closed source chamber is 2.2 × 103 cm−3, which, as calculations of neutron transport show, will provide 200 cm−3 in the chambers of a neutron EDM spectrometer connected to the source by a UCN guide. Experiments at PNPI with a full-scale UCN source model have demonstrated that a heat load of 60 W can be removed from the He-II in the converter at a temperature of 1.37 K. This fact confirms the practical possibility to implement low-temperature converters under “in-pile” conditions with large heat inflows. The review concludes with a presentation of various proposed options for a He-II based UCN source at the European Spallation Source.
{"title":"Development of UCN sources at PNPI","authors":"A. Serebrov, Vitaliy Lyamkin","doi":"10.3233/jnr-220007","DOIUrl":"https://doi.org/10.3233/jnr-220007","url":null,"abstract":"This article reviews the development of various sources for ultracold neutrons (UCNs) at the Petersburg Nuclear Physics Institute (PNPI). For 45 years, PNPI has proposed and manufactured cryogenic devices for neutron conversion to low energies. Based on beryllium, hydrogen and deuterium, they can be operated in the intense radiation fields near the core of a nuclear reactor. A more recently launched UCN source development utilizes superfluid helium (He-II) as conversion medium. Initially proposed and designed for PNPI’s old WWR-M reactor, the project has been reshaped to equip the institute’s PIK reactor with a modern UCN source of this type. The projected UCN density in the closed source chamber is 2.2 × 103 cm−3, which, as calculations of neutron transport show, will provide 200 cm−3 in the chambers of a neutron EDM spectrometer connected to the source by a UCN guide. Experiments at PNPI with a full-scale UCN source model have demonstrated that a heat load of 60 W can be removed from the He-II in the converter at a temperature of 1.37 K. This fact confirms the practical possibility to implement low-temperature converters under “in-pile” conditions with large heat inflows. The review concludes with a presentation of various proposed options for a He-II based UCN source at the European Spallation Source.","PeriodicalId":44708,"journal":{"name":"Journal of Neutron Research","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44082456","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
B. Mom, L. Thulliez, Eric Dumonteil, M. Binois, Y. Richet, J. Schwindling, A. Drouart
Facilities providing bright thermal neutron beams are of primary importance for various research topics. At CEA-Saclay, a compact accelerator driven neutron source, SONATE, is investigated in taking advantage of the IPHI accelerator able to deliver a 3 MeV proton beam with an intensity up to 100 mA. To optimize the performances of such a neutron source, it is necessary to maximize the thermal neutron flux while minimizing the contribution of other particles. In this work, optimization has been performed using the Monte Carlo code TOUCANS, a neutron transport code based on Geant4 developed at CEA-Saclay. This latter has been coupled to PROMETHEE, a software allowing multi-objective optimization for many simulation software. In this work the Kriging metamodel based approach is used to optimize a neutron beamdump. To take into account the various constraints, noise on the detection system and radiation protection issues, several beamdump configurations are evaluated. The variation of beamdump parameters makes it possible to identify the set of optimal solutions, the Pareto front. It allows to focus on the set of best choices and to choose wisely the best configurations. After describing the validation of TOUCANS on experimental tests performed from 2016 to 2022, the capability of such an approach will be presented.
{"title":"Simulation and design of an IPHI-based neutron source, first steps toward SONATE","authors":"B. Mom, L. Thulliez, Eric Dumonteil, M. Binois, Y. Richet, J. Schwindling, A. Drouart","doi":"10.3233/jnr-220027","DOIUrl":"https://doi.org/10.3233/jnr-220027","url":null,"abstract":"Facilities providing bright thermal neutron beams are of primary importance for various research topics. At CEA-Saclay, a compact accelerator driven neutron source, SONATE, is investigated in taking advantage of the IPHI accelerator able to deliver a 3 MeV proton beam with an intensity up to 100 mA. To optimize the performances of such a neutron source, it is necessary to maximize the thermal neutron flux while minimizing the contribution of other particles. In this work, optimization has been performed using the Monte Carlo code TOUCANS, a neutron transport code based on Geant4 developed at CEA-Saclay. This latter has been coupled to PROMETHEE, a software allowing multi-objective optimization for many simulation software. In this work the Kriging metamodel based approach is used to optimize a neutron beamdump. To take into account the various constraints, noise on the detection system and radiation protection issues, several beamdump configurations are evaluated. The variation of beamdump parameters makes it possible to identify the set of optimal solutions, the Pareto front. It allows to focus on the set of best choices and to choose wisely the best configurations. After describing the validation of TOUCANS on experimental tests performed from 2016 to 2022, the capability of such an approach will be presented.","PeriodicalId":44708,"journal":{"name":"Journal of Neutron Research","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47679548","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yujiro Ikeda, M. Teshigawara, M. Yan, C. Iwamoto, Kunihiro Fujita, Yutaka Abe, Y. Wakabayashi, A. Taketani, Takaoki Takanashi, M. Harada, T. Hashiguchi, Yutaka Yamagata, Yoshio Matsuzaki, B. Ma, M. Takamura, M. Mizuta, Makoto Goto, S. Ikeda, Tomohiro Kobayashi, Y. Otake
The RANS (RIKEN Accelerator driven Neutron Source), one of compact accelerator neutron sources (CANS), tries to expand its performance by installing a cold neutron which may provide new opportunities in many applications. RANS is a low power CANS with a proton beam of 7 MeV and 100 µA at maximum. A moderator system was constructed based on results of optimization design study with mesitylene. Recently, we have done performance tests aiming at showing characteristics as cold neutron source. Cryogenic mesitylene moderator was installed on a plug with a new target moderator reflector configuration of RANS. Experiment using a gas electron multiplier (GEM) detector was carried out to measure neutron spectra of the cold moderator. This paper describes performance of the cold moderator in terms of 1) Cold neutron gain of optimization design with respect to a polyethylene moderator, 2) Temperature dependency of cold neutron spectrum flux regarding scattering kernel (SK), and 3) comparison between experiment and calculation. A note is given for comparison between calculations with different SKs available. Also, two-dimensional imaging of cold and thermal neutron spectrum flux on the viewed surface is shown with a pinhole slit configuration.
{"title":"Experimental validation of cold neutron source performance with mesitylene moderator installed at RANS","authors":"Yujiro Ikeda, M. Teshigawara, M. Yan, C. Iwamoto, Kunihiro Fujita, Yutaka Abe, Y. Wakabayashi, A. Taketani, Takaoki Takanashi, M. Harada, T. Hashiguchi, Yutaka Yamagata, Yoshio Matsuzaki, B. Ma, M. Takamura, M. Mizuta, Makoto Goto, S. Ikeda, Tomohiro Kobayashi, Y. Otake","doi":"10.3233/jnr-220034","DOIUrl":"https://doi.org/10.3233/jnr-220034","url":null,"abstract":"The RANS (RIKEN Accelerator driven Neutron Source), one of compact accelerator neutron sources (CANS), tries to expand its performance by installing a cold neutron which may provide new opportunities in many applications. RANS is a low power CANS with a proton beam of 7 MeV and 100 µA at maximum. A moderator system was constructed based on results of optimization design study with mesitylene. Recently, we have done performance tests aiming at showing characteristics as cold neutron source. Cryogenic mesitylene moderator was installed on a plug with a new target moderator reflector configuration of RANS. Experiment using a gas electron multiplier (GEM) detector was carried out to measure neutron spectra of the cold moderator. This paper describes performance of the cold moderator in terms of 1) Cold neutron gain of optimization design with respect to a polyethylene moderator, 2) Temperature dependency of cold neutron spectrum flux regarding scattering kernel (SK), and 3) comparison between experiment and calculation. A note is given for comparison between calculations with different SKs available. Also, two-dimensional imaging of cold and thermal neutron spectrum flux on the viewed surface is shown with a pinhole slit configuration.","PeriodicalId":44708,"journal":{"name":"Journal of Neutron Research","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41893679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Schwindling, B. Annighöfer, N. Chauvin, J. Meuriot, B. Mom, Frédéric Ott, N. Sellami, L. Thulliez
Following tests of low power bulk Beryllium targets in 2016–2020, a high power target was designed, built and tested at the High Intensity Proton Injector (IPHI) at CEA Paris–Saclay. The design of the target and the results of the tests will be described.
{"title":"Long term operation of a 30 kW Beryllium target at IPHI","authors":"J. Schwindling, B. Annighöfer, N. Chauvin, J. Meuriot, B. Mom, Frédéric Ott, N. Sellami, L. Thulliez","doi":"10.3233/jnr-220024","DOIUrl":"https://doi.org/10.3233/jnr-220024","url":null,"abstract":"Following tests of low power bulk Beryllium targets in 2016–2020, a high power target was designed, built and tested at the High Intensity Proton Injector (IPHI) at CEA Paris–Saclay. The design of the target and the results of the tests will be described.","PeriodicalId":44708,"journal":{"name":"Journal of Neutron Research","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48131215","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The European Spallation Source (ESS) in Lund, Sweden, is going to be the most powerful spallation neutron source in the world. As one subsystem of the Target Station, which was develop and built at Central Institute of Engineering, Electronics and Analytics – Engineering and Technology (ZEA-1) of Forschungszentrum Juelich, the cold Moderator slows down high energy neutrons from the spallation process. To gain maximum neutron flux intensities along with high system availability for condensed and soft matter research, an optimized liquid hydrogen Moderator circuit has been developed. Hydrogen with a pressure around 1 MPa, a temperature around 20 K, and a para-hydrogen fraction of at least 0.995 will be utilized to interact with neutrons in a unique cold Moderator vessel arrangement. Hydrogen conversion from ortho- to para-hydrogen will be controlled using a catalyst. Two turbo pumps are arranged in series and circulate the cryogen. A helium refrigerator, the Target Moderator Cryoplant (TMCP), continuously recools the hydrogen mass flow. The pressure stabilization is achieved by a pressure control buffer. The individual ESS Cryogenic Moderator System (CMS) components, the first and second generation of hydrogen Moderators (BF1 and BF2) and a first draft of a deuterium Moderator upgrade are described in detail.
{"title":"Cryogenic hydrogen Moderator infrastructure at ESS","authors":"Y. Bessler, G. Natour","doi":"10.3233/jnr-220033","DOIUrl":"https://doi.org/10.3233/jnr-220033","url":null,"abstract":"The European Spallation Source (ESS) in Lund, Sweden, is going to be the most powerful spallation neutron source in the world. As one subsystem of the Target Station, which was develop and built at Central Institute of Engineering, Electronics and Analytics – Engineering and Technology (ZEA-1) of Forschungszentrum Juelich, the cold Moderator slows down high energy neutrons from the spallation process. To gain maximum neutron flux intensities along with high system availability for condensed and soft matter research, an optimized liquid hydrogen Moderator circuit has been developed. Hydrogen with a pressure around 1 MPa, a temperature around 20 K, and a para-hydrogen fraction of at least 0.995 will be utilized to interact with neutrons in a unique cold Moderator vessel arrangement. Hydrogen conversion from ortho- to para-hydrogen will be controlled using a catalyst. Two turbo pumps are arranged in series and circulate the cryogen. A helium refrigerator, the Target Moderator Cryoplant (TMCP), continuously recools the hydrogen mass flow. The pressure stabilization is achieved by a pressure control buffer. The individual ESS Cryogenic Moderator System (CMS) components, the first and second generation of hydrogen Moderators (BF1 and BF2) and a first draft of a deuterium Moderator upgrade are described in detail.","PeriodicalId":44708,"journal":{"name":"Journal of Neutron Research","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43668799","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Frost, M. Elfman, K. Fissum, Markus Kristensson, P. Kristiansson, N. Mauritzson, J. Pallon, H. Perrey, G. Pédehontaa-Hiaa, A. Sjöland, K. Stenström
The Applied Nuclear Physics Group at Lund University is constructing a prototype CANS (Compact Accelerator-driven Neutron Source). The CANS is based around a 3 MV, single-ended, Pelletron accelerator, which is used to impinge a 2.8 MeV deuterium beam into a beryllium target. The anticipated neutron production will be on the order of 1010 n/s in 4π sr. A further upgrade to the ion source of the Pelletron is expected to increase neutron production to 1011 n/s. Neutron energies will be up to 9 MeV with peak emission at ∼5 MeV. Shielding and moderation will be provided by a large water tank surrounding the target, with three exit ports to allow neutrons of different energies to be directed to experiments. The design is supported by simulation results which predict fast-neutron fluxes of 9×104 to 5×106 n/cm2/s, and thermal-neutron fluxes of 1×104 to 5×104 n/cm2/s to be readily obtainable with a 10 µA deuteron beam.
{"title":"Development of a Pelletron-based compact neutron source","authors":"R. Frost, M. Elfman, K. Fissum, Markus Kristensson, P. Kristiansson, N. Mauritzson, J. Pallon, H. Perrey, G. Pédehontaa-Hiaa, A. Sjöland, K. Stenström","doi":"10.3233/jnr-220026","DOIUrl":"https://doi.org/10.3233/jnr-220026","url":null,"abstract":"The Applied Nuclear Physics Group at Lund University is constructing a prototype CANS (Compact Accelerator-driven Neutron Source). The CANS is based around a 3 MV, single-ended, Pelletron accelerator, which is used to impinge a 2.8 MeV deuterium beam into a beryllium target. The anticipated neutron production will be on the order of 1010 n/s in 4π sr. A further upgrade to the ion source of the Pelletron is expected to increase neutron production to 1011 n/s. Neutron energies will be up to 9 MeV with peak emission at ∼5 MeV. Shielding and moderation will be provided by a large water tank surrounding the target, with three exit ports to allow neutrons of different energies to be directed to experiments. The design is supported by simulation results which predict fast-neutron fluxes of 9×104 to 5×106 n/cm2/s, and thermal-neutron fluxes of 1×104 to 5×104 n/cm2/s to be readily obtainable with a 10 µA deuteron beam.","PeriodicalId":44708,"journal":{"name":"Journal of Neutron Research","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43119832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This note is based on a talk given at the “Workshop on Very Cold and Ultra Cold Neutron Sources for ESS”. It presents several arguments in favor of using very cold neutrons (VCN) for neutron – antineutron ( n − n ‾) searches. It also proposes a scheme for the implementation of a solid-deuterium VCN converter with a fluorinated detonation nanodiamond (F-DND) reflector that is optimized for an ( n − n ‾) experiment with VCN. An analysis of the feasibility of such a source, as well as its effect on the ( n − n ‾) experiment are beyond the scope of this short note. They will, however, be pursued in the near future in a collaborative manner.
{"title":"Why very cold neutrons could be useful for neutron antineutron oscillation searches","authors":"V. Nesvizhevsky","doi":"10.3233/jnr-220003","DOIUrl":"https://doi.org/10.3233/jnr-220003","url":null,"abstract":"This note is based on a talk given at the “Workshop on Very Cold and Ultra Cold Neutron Sources for ESS”. It presents several arguments in favor of using very cold neutrons (VCN) for neutron – antineutron ( n − n ‾) searches. It also proposes a scheme for the implementation of a solid-deuterium VCN converter with a fluorinated detonation nanodiamond (F-DND) reflector that is optimized for an ( n − n ‾) experiment with VCN. An analysis of the feasibility of such a source, as well as its effect on the ( n − n ‾) experiment are beyond the scope of this short note. They will, however, be pursued in the near future in a collaborative manner.","PeriodicalId":44708,"journal":{"name":"Journal of Neutron Research","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47569826","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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