The Experts below are selected from a list of 288 Experts worldwide ranked by ideXlab platform
L Obst - One of the best experts on this subject based on the ideXlab platform.
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first demonstration of multi mev proton acceleration from a Cryogenic Hydrogen ribbon target
Plasma Physics and Controlled Fusion, 2018Co-Authors: S D Kraft, L Obst, Josefine Metzkesng, H P Schlenvoigt, K Zeil, Sylvain Michaux, D Chatain, J P Perin, S N ChenAbstract:We show efficient laser driven proton acceleration up to 14 MeV from a 62 μm thick Cryogenic Hydrogen ribbon. Pulses of the short pulse laser ELFIE at LULI with a pulse length of ≈350 fs at an energy of 8 J per pulse are directed onto the target. The results are compared to proton spectra from metal and plastic foils with different thicknesses and show a similarly good performance both in maximum energy as well as in proton number. Thus, this target type is a promising candidate for experiments with high repetition rate laser systems.
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high repetition rate multi mev proton source from Cryogenic Hydrogen jets
Applied Physics Letters, 2017Co-Authors: M Gauthier, M J Macdonald, Chandra Curry, S Gode, Florianemanuel Brack, J Metzkes, L ObstAbstract:We report on a high repetition rate proton source produced by high-intensity laser irradiation of a continuously flowing, Cryogenic Hydrogen jet. The proton energy spectra are recorded at 1 Hz for Draco laser powers of 6, 20, 40, and 100 TW. The source delivers ∼1013 protons/MeV/sr/min. We find that the average proton number over one minute, at energies sufficiently far from the cut-off energy, is robust to laser-target overlap and nearly constant. This work is therefore a first step towards pulsed laser-driven proton sources for time-resolved radiation damage studies and applications which require quasi-continuous doses at MeV energies.
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Efficient laser-driven proton acceleration from cylindrical and planar Cryogenic Hydrogen jets
Scientific Reports, 2017Co-Authors: L Obst, S Gode, Florianemanuel Brack, Martin Rehwald, João Branco, Stefan Bock, Michael Bussmann, Thomas E. Cowan, Chandra B. Curry, Frederico FiuzaAbstract:We report on recent experimental results deploying a continuous Cryogenic Hydrogen jet as a debris-free, renewable laser-driven source of pure proton beams generated at the 150 TW ultrashort pulse laser Draco. Efficient proton acceleration reaching cut-off energies of up to 20 MeV with particle numbers exceeding 10^9 particles per MeV per steradian is demonstrated, showing for the first time that the acceleration performance is comparable to solid foil targets with thicknesses in the micrometer range. Two different target geometries are presented and their proton beam deliverance characterized: cylindrical (∅ 5 μm) and planar (20 μm × 2 μm). In both cases typical Target Normal Sheath Acceleration emission patterns with exponential proton energy spectra are detected. Significantly higher proton numbers in laser-forward direction are observed when deploying the planar jet as compared to the cylindrical jet case. This is confirmed by two-dimensional Particle-in-Cell (2D3V PIC) simulations, which demonstrate that the planar jet proves favorable as its geometry leads to more optimized acceleration conditions.
K. Ohtsu - One of the best experts on this subject based on the ideXlab platform.
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Operational Experiences of J-PARC Cryogenic Hydrogen system for a spallation neutron source
IOP Conference Series: Materials Science and Engineering, 2015Co-Authors: Hideki Tatsumoto, K. Ohtsu, Y. Kawakami, K Aoyagi, H MutoAbstract:The Japan Proton Accelerator Research Complex (J-PARC) Cryogenic Hydrogen system was completed in April 2008. The proton beam power was gradually increased to 500 kW. A trial 600-kW proton beam operation was successfully completed in April 2015. We achieved long-lasting operation for more than three months. However, thus far, we encountered several problems such as unstable operation of the helium refrigerator because of some impurities, failure of a welded bellows of an accumulator, and Hydrogen pump issues. Furthermore, the Great East Japan Earthquake was experienced during the Cryogenic Hydrogen system operation in March 2011. In this study, we describe the operation characteristics and our experiences with the J-PARC Cryogenic Hydrogen system.
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Pressure and temperature fluctuation simulation of J-PARC Cryogenic Hydrogen system
IOP Conference Series: Materials Science and Engineering, 2015Co-Authors: Hideki Tatsumoto, K. Ohtsu, Y. KawakamiAbstract:The J-PARC Cryogenic Hydrogen system provides supercritical Cryogenic Hydrogen to the moderators at a pressure of 1.5 MPa and temperature of 18 K and removes 3.8 kW of nuclear heat from the 1 MW proton beam operation. We prepared a heater for thermal compensation and an accumulator, with a bellows structure for volume control, to mitigate the pressure fluctuation caused by switching the proton beam on and off. In this study, a 1-D simulation code named DiSC-SH2 was developed to understand the propagation of pressure and temperature propagations through the Hydrogen loop due to on and off switching of the proton beam. We confirmed that the simulated dynamic behaviors in the Hydrogen loop for 300-kW and 500-kW proton beam operations agree well with the experimental data under the same conditions.
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operational characteristics of the j parc Cryogenic Hydrogen system for a spallation neutron source
ADVANCES IN CRYOGENIC ENGINEERING: Transactions of the Cryogenic Engineering Conference - CEC, 2014Co-Authors: H Tatsumoto, K. Ohtsu, Y. Kawakami, Makoto TeshigawaraAbstract:The J-PARC Cryogenic Hydrogen system provides supercritical Hydrogen with the para-Hydrogen concentration of more than 99 % and the temperature of less than 20 K to three moderators so as to provide cold pulsed neutron beams of a higher neutronic performance. Furthermore, the temperature fluctuation of the feed Hydrogen stream is required to be within ± 0.25 K. A stable 300-kW proton beam operation has been carried out since November 2012. The para-Hydrogen concentrations were measured during the cool-down process. It is confirmed that para-Hydrogen always exists in the equilibrium concentration because of the installation of an ortho-para Hydrogen convertor. Propagation characteristics of temperature fluctuation were measured by temporarily changing the heater power under off-beam condition to clarify the effects of a heater control for thermal compensation on the feed temperature fluctuation. The experimental data gave an allowable temperature fluctuation of ± 1.05 K. It is clarified through a 286-kW and a 524-kW proton beam operations that the heater control would be applicable for the 1-MW proton beam operation by extrapolating from the experimental data.
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Dynamic behavior of the Cryogenic Hydrogen system using only a heater control
2012Co-Authors: Hideki Tatsumoto, K. Ohtsu, Y. Kawakami, H Sakurayama, Masatoshi FutakawaAbstract:The J-PARC Cryogenic Hydrogen system provides supercritical Hydrogen to three moderators and absorbs a nuclear heating of 3.75 kW for a 1-MW proton beam operation. A pressure control system, which consists of a heater for the thermal compensation and a Cryogenic accumulator with a bellows acting as a volume controller, is prepared to mitigate a pressure fluctuation caused by the sudden heat load of kW-order. Stable operation with a 120-kW proton beam power, where the heat load is 450 W, has been conducted since November 2009. However, a major problem with Cryogenic accumulator occurred during a short maintenance period in February 2010. In order to resume the 120-kW proton beam operation as soon as possible, an operational approach without using the Cryogenic accumulator was studied and the Hydrogen loop was partially altered. It was confirmed through an on-beam commissioning that only the approach could successfully mitigate the pressure fluctuation below the allowable value of 0.1 MPa, although it was e...
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design of a high power heater for the Cryogenic Hydrogen system at j parc
Cryogenics, 2011Co-Authors: H Tatsumoto, K. Ohtsu, Fujio Maekawa, T Kato, Masatoshi FutakawaAbstract:Abstract The Cryogenic Hydrogen system, which provides the supercritical Hydrogen with the pressure of 1.5 MPa and the temperature of around 20 K, adopts to moderate and convert high-energy neutrons into cold neutrons for neutron scattering experiments in the J-PARC. Large pressure fluctuation caused by the intense pulsed-proton-beam injection and trip should be mitigated by both an active heater control and a passive accumulator control. A compact high power heater should be required to compensate the heat load corresponding to the nuclear heating while the proton beam stopping. In this study, the high power heater used in the Cryogenic Hydrogen was designed and a numerical analysis was performed. Then the results confirmed that the heater could apply kW-order heat powers to supercritical Hydrogen without any disturbance.
Masatoshi Futakawa - One of the best experts on this subject based on the ideXlab platform.
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Dynamic behavior of the Cryogenic Hydrogen system using only a heater control
2012Co-Authors: Hideki Tatsumoto, K. Ohtsu, Y. Kawakami, H Sakurayama, Masatoshi FutakawaAbstract:The J-PARC Cryogenic Hydrogen system provides supercritical Hydrogen to three moderators and absorbs a nuclear heating of 3.75 kW for a 1-MW proton beam operation. A pressure control system, which consists of a heater for the thermal compensation and a Cryogenic accumulator with a bellows acting as a volume controller, is prepared to mitigate a pressure fluctuation caused by the sudden heat load of kW-order. Stable operation with a 120-kW proton beam power, where the heat load is 450 W, has been conducted since November 2009. However, a major problem with Cryogenic accumulator occurred during a short maintenance period in February 2010. In order to resume the 120-kW proton beam operation as soon as possible, an operational approach without using the Cryogenic accumulator was studied and the Hydrogen loop was partially altered. It was confirmed through an on-beam commissioning that only the approach could successfully mitigate the pressure fluctuation below the allowable value of 0.1 MPa, although it was e...
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design of a high power heater for the Cryogenic Hydrogen system at j parc
Cryogenics, 2011Co-Authors: H Tatsumoto, K. Ohtsu, Fujio Maekawa, T Kato, Masatoshi FutakawaAbstract:Abstract The Cryogenic Hydrogen system, which provides the supercritical Hydrogen with the pressure of 1.5 MPa and the temperature of around 20 K, adopts to moderate and convert high-energy neutrons into cold neutrons for neutron scattering experiments in the J-PARC. Large pressure fluctuation caused by the intense pulsed-proton-beam injection and trip should be mitigated by both an active heater control and a passive accumulator control. A compact high power heater should be required to compensate the heat load corresponding to the nuclear heating while the proton beam stopping. In this study, the high power heater used in the Cryogenic Hydrogen was designed and a numerical analysis was performed. Then the results confirmed that the heater could apply kW-order heat powers to supercritical Hydrogen without any disturbance.
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development of the Cryogenic Hydrogen system for a spallation neutrton source in j parc
TRANSACTIONS OF THE CRYOGENIC ENGINEERING CONFERENCE—CEC: Advances in Cryogenic Engineering, 2010Co-Authors: H Tatsumoto, K. Ohtsu, Y. Kawakami, T Kato, T Uehara, H Sakurayama, Masatoshi FutakawaAbstract:An intense spallation neutron source (JSNS) driven by a proton beam of 1‐MW has been constructed as one of the main experimental facilities in J‐PARC. Supercritical Hydrogen at around 20 K and 1.5 MPa was selected as a moderator material in JSNS. Three kinds of Hydrogen moderators (coupled, decoupled, and poisoned) were installed to provide pulsed neutron beam of higher neutronic performance. The total nuclear heating in the moderators was estimated to be 3.75 kW for a proton beam power of 1 MW. The Cryogenic Hydrogen system, where the Hydrogen circulation system is cooled by a helium refrigerator system with the refrigerator capacity of 6.45 kW at 15.6 K, provides the supercritical Hydrogen for the moderators and absorbs nuclear heating in the moderators. The off‐beam commissioning has confirmed that the Cryogenic Hydrogen system can be cooled down to 18 K within 19 hours. The supercritical Hydrogen with a mass flow rate of 190 g/s can be circulated in the rated condition. It was verified that the cryoge...
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DEVELOPMENT OF THE Cryogenic Hydrogen SYSTEM FOR A SPALLATION NEUTRTON SOURCE IN J‐PARC
2010Co-Authors: Hideki Tatsumoto, K. Ohtsu, Y. Kawakami, T Kato, T Uehara, H Sakurayama, Masatoshi FutakawaAbstract:An intense spallation neutron source (JSNS) driven by a proton beam of 1‐MW has been constructed as one of the main experimental facilities in J‐PARC. Supercritical Hydrogen at around 20 K and 1.5 MPa was selected as a moderator material in JSNS. Three kinds of Hydrogen moderators (coupled, decoupled, and poisoned) were installed to provide pulsed neutron beam of higher neutronic performance. The total nuclear heating in the moderators was estimated to be 3.75 kW for a proton beam power of 1 MW. The Cryogenic Hydrogen system, where the Hydrogen circulation system is cooled by a helium refrigerator system with the refrigerator capacity of 6.45 kW at 15.6 K, provides the supercritical Hydrogen for the moderators and absorbs nuclear heating in the moderators. The off‐beam commissioning has confirmed that the Cryogenic Hydrogen system can be cooled down to 18 K within 19 hours. The supercritical Hydrogen with a mass flow rate of 190 g/s can be circulated in the rated condition. It was verified that the cryoge...
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Development of a simulation code for a cool-down process of the Cryogenic Hydrogen system
2010Co-Authors: Hideki Tatsumoto, K. Ohtsu, T Kato, Masatoshi FutakawaAbstract:Supercritical Hydrogen with a pressure of 1.5 MPa and a temperature of 20 K has been selected as a moderator material in an intense spallation neutron source (JSNS), which is one of main experimental facilities in J‐PARC. The Cryogenic Hydrogen system, in which a Hydrogen circulation system is cooled by a helium refrigerator with the refrigeration power of 6.45 kW at 15.5 K, has been designed to provide the supercritical Hydrogen to the moderator and to remove the nuclear heating generated there. In this study, we have developed a simulation code that predicts temperature behaviors in the Hydrogen circulation system during its cool‐down process. Cool‐down process analyses have been performed, and an operational method for the cool‐down process has been studied. The analytical results indicate that the Hydrogen circulation system would be able to be cooled down to 18 K within 19 hours.
T Kato - One of the best experts on this subject based on the ideXlab platform.
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design of a high power heater for the Cryogenic Hydrogen system at j parc
Cryogenics, 2011Co-Authors: H Tatsumoto, K. Ohtsu, Fujio Maekawa, T Kato, Masatoshi FutakawaAbstract:Abstract The Cryogenic Hydrogen system, which provides the supercritical Hydrogen with the pressure of 1.5 MPa and the temperature of around 20 K, adopts to moderate and convert high-energy neutrons into cold neutrons for neutron scattering experiments in the J-PARC. Large pressure fluctuation caused by the intense pulsed-proton-beam injection and trip should be mitigated by both an active heater control and a passive accumulator control. A compact high power heater should be required to compensate the heat load corresponding to the nuclear heating while the proton beam stopping. In this study, the high power heater used in the Cryogenic Hydrogen was designed and a numerical analysis was performed. Then the results confirmed that the heater could apply kW-order heat powers to supercritical Hydrogen without any disturbance.
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development of the Cryogenic Hydrogen system for a spallation neutrton source in j parc
TRANSACTIONS OF THE CRYOGENIC ENGINEERING CONFERENCE—CEC: Advances in Cryogenic Engineering, 2010Co-Authors: H Tatsumoto, K. Ohtsu, Y. Kawakami, T Kato, T Uehara, H Sakurayama, Masatoshi FutakawaAbstract:An intense spallation neutron source (JSNS) driven by a proton beam of 1‐MW has been constructed as one of the main experimental facilities in J‐PARC. Supercritical Hydrogen at around 20 K and 1.5 MPa was selected as a moderator material in JSNS. Three kinds of Hydrogen moderators (coupled, decoupled, and poisoned) were installed to provide pulsed neutron beam of higher neutronic performance. The total nuclear heating in the moderators was estimated to be 3.75 kW for a proton beam power of 1 MW. The Cryogenic Hydrogen system, where the Hydrogen circulation system is cooled by a helium refrigerator system with the refrigerator capacity of 6.45 kW at 15.6 K, provides the supercritical Hydrogen for the moderators and absorbs nuclear heating in the moderators. The off‐beam commissioning has confirmed that the Cryogenic Hydrogen system can be cooled down to 18 K within 19 hours. The supercritical Hydrogen with a mass flow rate of 190 g/s can be circulated in the rated condition. It was verified that the cryoge...
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DEVELOPMENT OF THE Cryogenic Hydrogen SYSTEM FOR A SPALLATION NEUTRTON SOURCE IN J‐PARC
2010Co-Authors: Hideki Tatsumoto, K. Ohtsu, Y. Kawakami, T Kato, T Uehara, H Sakurayama, Masatoshi FutakawaAbstract:An intense spallation neutron source (JSNS) driven by a proton beam of 1‐MW has been constructed as one of the main experimental facilities in J‐PARC. Supercritical Hydrogen at around 20 K and 1.5 MPa was selected as a moderator material in JSNS. Three kinds of Hydrogen moderators (coupled, decoupled, and poisoned) were installed to provide pulsed neutron beam of higher neutronic performance. The total nuclear heating in the moderators was estimated to be 3.75 kW for a proton beam power of 1 MW. The Cryogenic Hydrogen system, where the Hydrogen circulation system is cooled by a helium refrigerator system with the refrigerator capacity of 6.45 kW at 15.6 K, provides the supercritical Hydrogen for the moderators and absorbs nuclear heating in the moderators. The off‐beam commissioning has confirmed that the Cryogenic Hydrogen system can be cooled down to 18 K within 19 hours. The supercritical Hydrogen with a mass flow rate of 190 g/s can be circulated in the rated condition. It was verified that the cryoge...
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Development of a simulation code for a cool-down process of the Cryogenic Hydrogen system
2010Co-Authors: Hideki Tatsumoto, K. Ohtsu, T Kato, Masatoshi FutakawaAbstract:Supercritical Hydrogen with a pressure of 1.5 MPa and a temperature of 20 K has been selected as a moderator material in an intense spallation neutron source (JSNS), which is one of main experimental facilities in J‐PARC. The Cryogenic Hydrogen system, in which a Hydrogen circulation system is cooled by a helium refrigerator with the refrigeration power of 6.45 kW at 15.5 K, has been designed to provide the supercritical Hydrogen to the moderator and to remove the nuclear heating generated there. In this study, we have developed a simulation code that predicts temperature behaviors in the Hydrogen circulation system during its cool‐down process. Cool‐down process analyses have been performed, and an operational method for the cool‐down process has been studied. The analytical results indicate that the Hydrogen circulation system would be able to be cooled down to 18 K within 19 hours.
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pressure fluctuation behavior in the Cryogenic Hydrogen system caused by a 100 kw proton beam injection
TRANSACTIONS OF THE CRYOGENIC ENGINEERING CONFERENCE—CEC: Advances in Cryogenic Engineering, 2010Co-Authors: H Tatsumoto, K. Ohtsu, Y. Kawakami, S Hasegawa, T Kato, T Uehara, H Sakurayama, Masatoshi FutakawaAbstract:Supercritical Hydrogen (1.5 MPa and around 20 K) has been selected as a moderator material for the intense spallation neutron source (JSNS) in J‐PARC. The Cryogenic Hydrogen system provides the supercritical Hydrogen for the moderators and removes the nuclear heating at the moderators, which is estimated to be 3.8 kW for a proton beam power of 1 MW. The pressure control system was designed to mitigate pressure fluctuation caused by suddenly turning a proton beam on and off, which is composed of a heater as an active controller for thermal compensation and an accumulator as a passive volume controller. A 109 kW proton beam was injected to the JSNS in December 2007. The pressure fluctuation behaviors were studied for the 109 kW proton beam operation. As soon as the proton beam was injected, the accumulator spontaneously started to constrict. The heater control succeeded in maintaining a constant heat load applied to the Cryogenic Hydrogen system. The pressure control system successfully reduced the pressure...
Hideki Tatsumoto - One of the best experts on this subject based on the ideXlab platform.
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Operational Experiences of J-PARC Cryogenic Hydrogen system for a spallation neutron source
IOP Conference Series: Materials Science and Engineering, 2015Co-Authors: Hideki Tatsumoto, K. Ohtsu, Y. Kawakami, K Aoyagi, H MutoAbstract:The Japan Proton Accelerator Research Complex (J-PARC) Cryogenic Hydrogen system was completed in April 2008. The proton beam power was gradually increased to 500 kW. A trial 600-kW proton beam operation was successfully completed in April 2015. We achieved long-lasting operation for more than three months. However, thus far, we encountered several problems such as unstable operation of the helium refrigerator because of some impurities, failure of a welded bellows of an accumulator, and Hydrogen pump issues. Furthermore, the Great East Japan Earthquake was experienced during the Cryogenic Hydrogen system operation in March 2011. In this study, we describe the operation characteristics and our experiences with the J-PARC Cryogenic Hydrogen system.
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Pressure and temperature fluctuation simulation of J-PARC Cryogenic Hydrogen system
IOP Conference Series: Materials Science and Engineering, 2015Co-Authors: Hideki Tatsumoto, K. Ohtsu, Y. KawakamiAbstract:The J-PARC Cryogenic Hydrogen system provides supercritical Cryogenic Hydrogen to the moderators at a pressure of 1.5 MPa and temperature of 18 K and removes 3.8 kW of nuclear heat from the 1 MW proton beam operation. We prepared a heater for thermal compensation and an accumulator, with a bellows structure for volume control, to mitigate the pressure fluctuation caused by switching the proton beam on and off. In this study, a 1-D simulation code named DiSC-SH2 was developed to understand the propagation of pressure and temperature propagations through the Hydrogen loop due to on and off switching of the proton beam. We confirmed that the simulated dynamic behaviors in the Hydrogen loop for 300-kW and 500-kW proton beam operations agree well with the experimental data under the same conditions.
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Dynamic behavior of the Cryogenic Hydrogen system using only a heater control
2012Co-Authors: Hideki Tatsumoto, K. Ohtsu, Y. Kawakami, H Sakurayama, Masatoshi FutakawaAbstract:The J-PARC Cryogenic Hydrogen system provides supercritical Hydrogen to three moderators and absorbs a nuclear heating of 3.75 kW for a 1-MW proton beam operation. A pressure control system, which consists of a heater for the thermal compensation and a Cryogenic accumulator with a bellows acting as a volume controller, is prepared to mitigate a pressure fluctuation caused by the sudden heat load of kW-order. Stable operation with a 120-kW proton beam power, where the heat load is 450 W, has been conducted since November 2009. However, a major problem with Cryogenic accumulator occurred during a short maintenance period in February 2010. In order to resume the 120-kW proton beam operation as soon as possible, an operational approach without using the Cryogenic accumulator was studied and the Hydrogen loop was partially altered. It was confirmed through an on-beam commissioning that only the approach could successfully mitigate the pressure fluctuation below the allowable value of 0.1 MPa, although it was e...
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DEVELOPMENT OF THE Cryogenic Hydrogen SYSTEM FOR A SPALLATION NEUTRTON SOURCE IN J‐PARC
2010Co-Authors: Hideki Tatsumoto, K. Ohtsu, Y. Kawakami, T Kato, T Uehara, H Sakurayama, Masatoshi FutakawaAbstract:An intense spallation neutron source (JSNS) driven by a proton beam of 1‐MW has been constructed as one of the main experimental facilities in J‐PARC. Supercritical Hydrogen at around 20 K and 1.5 MPa was selected as a moderator material in JSNS. Three kinds of Hydrogen moderators (coupled, decoupled, and poisoned) were installed to provide pulsed neutron beam of higher neutronic performance. The total nuclear heating in the moderators was estimated to be 3.75 kW for a proton beam power of 1 MW. The Cryogenic Hydrogen system, where the Hydrogen circulation system is cooled by a helium refrigerator system with the refrigerator capacity of 6.45 kW at 15.6 K, provides the supercritical Hydrogen for the moderators and absorbs nuclear heating in the moderators. The off‐beam commissioning has confirmed that the Cryogenic Hydrogen system can be cooled down to 18 K within 19 hours. The supercritical Hydrogen with a mass flow rate of 190 g/s can be circulated in the rated condition. It was verified that the cryoge...
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Development of a simulation code for a cool-down process of the Cryogenic Hydrogen system
2010Co-Authors: Hideki Tatsumoto, K. Ohtsu, T Kato, Masatoshi FutakawaAbstract:Supercritical Hydrogen with a pressure of 1.5 MPa and a temperature of 20 K has been selected as a moderator material in an intense spallation neutron source (JSNS), which is one of main experimental facilities in J‐PARC. The Cryogenic Hydrogen system, in which a Hydrogen circulation system is cooled by a helium refrigerator with the refrigeration power of 6.45 kW at 15.5 K, has been designed to provide the supercritical Hydrogen to the moderator and to remove the nuclear heating generated there. In this study, we have developed a simulation code that predicts temperature behaviors in the Hydrogen circulation system during its cool‐down process. Cool‐down process analyses have been performed, and an operational method for the cool‐down process has been studied. The analytical results indicate that the Hydrogen circulation system would be able to be cooled down to 18 K within 19 hours.