Absolute calibration of the JT-60U neutron monitors using a 252Cf neutron sourcea)

Nishitani, T.; Takeuchi, Hiroshi; Kondoh, T.; Itoh, Takaò; Kuriyama, M.; Ikeda, Yoshitaka; Iguchi, Tetsuo; Barnes, Cris W.

doi:10.1063/1.1143439

Cited by 82 publications

(58 citation statements)

References 10 publications

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“…International Thermonuclear Experimental Reactor (ITER) requires a measurement for the neutron source strength of 10 7 dynamic range, a temporal resolution of 1 ms, and an accuracy of 10%. In present large tokamaks such as JET, 1 TFTR, 2 or JT-60U, 3 the temporal measurement of neutron flux has been carried out using 235 U or 238 U fission chambers installed outside the vacuum vessel. ITER has thick components such as a blanket and vacuum vessel in addition to diagnostics equipment and heating systems.…”

Section: Introductionmentioning

confidence: 99%

First measurement of time-resolved neutron yield on JT-60U using a microfission chamber

Hayashi

Nishitani

Ishikawa

2004

Review of Scientific Instruments

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Microfission chambers, which are pencil sized ionization chamber containing fissile material inside, will be installed in the vacuum vessel as neutron monitors for International Thermonuclear Experimental Reactor (ITER). We have performed first measurements of the detector installed between the vacuum vessel and toroidal coils on JT-60U. The technical validity as a neutron monitor, such as magnetic field effect and electromagnetic noises from the plasma and heating devices, has been investigated. The detector had an excellent linearity with a 235 U fission chamber as a neutron monitor on JT-60U with the standard deviation of 3% except for some noise signals. The electromagnetic noises were caused by neutral beam injection (NBI) breakdowns, probably due to long wiring between the detector and the preamplifier. In case of plasma disruption, improper signals have not been observed. The magnetic field effect also has not been observed up to 2 T. In JT-60U, we confirmed availability of the micro fission chamber as a neutron monitor over three decades of neutron source strength up to 1.3ϫ 10 16 neutrons/ s with 1 ms temporal resolution. The biggest weakness in the detector was its noise sensitivity to NBI breakdowns. Therefore, by suppressing the electromagnetic noise, microfission chambers can be available as neutron monitors for ITER.

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Section: Introductionmentioning

confidence: 99%

First measurement of time-resolved neutron yield on JT-60U using a microfission chamber

Hayashi

Nishitani

Ishikawa

2004

Review of Scientific Instruments

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“…This chamber is the same as that employed in JT-60U deuterium operation. 15 Expected counting rate of the NFM system with this chamber is in a range of 10 8 -10 9 counts/s. Actually, more precise evaluations on neutron transport and expected neutron counting rate in the full three-dimensional configuration have been carried out by using the MCNP code.…”

Section: A Detector and Its Arrangement On Lhdmentioning

confidence: 99%

Wide dynamic range neutron flux monitor having fast time response for the Large Helical Device

Isobe

Ogawa

Miyake

et al. 2014

Review of Scientific Instruments

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A fast time response, wide dynamic range neutron flux monitor has been developed toward the LHD deuterium operation by using leading-edge signal processing technologies providing maximum counting rate up to ∼5 × 109 counts/s. Because a maximum total neutron emission rate over 1 × 1016 n/s is predicted in neutral beam-heated LHD plasmas, fast response and wide dynamic range capabilities of the system are essential. Preliminary tests have demonstrated successful performance as a wide dynamic range monitor along the design.

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“…where R p is the major radius, a p is the minor radius, Z p is the vertical shift of the plasma center, is the ellipticity 11) . In addition, we considered the plasma triangularity in the expressions.…”

Section: Calculationmentioning

confidence: 99%

Neutronic Analysis of Fusion Tokamak Devices by PHITS

Sukegawa

Takiyoshi

Amano

et al. 2011

Progress in Nuclear Science and Technology

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A complete 3D neutronic analysis by PHITS (Particle and Heavy Ion Transport code System) has been performed for fusion tokamaku devices such as JT-60U device and JT-60 Superconducting tokamak device (JT-60 Super Advanced). The mono-energetic neutrons (E n =2.45 MeV) of the DD fusion devices are used for the neutron source in the analysis. The visual neutron flux distribution for the estimation of the port streaming and the dose rate around the fusion tokamak devices has been calculated by the PHITS. The PHITS analysis makes it clear that the effect of the port streaming of superconducting fusion tokamak device with the cryostat is crucial and the calculated neutron spectrum results by PHITS agree with the MCNP-4C2 results.

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Absolute calibration of the JT-60U neutron monitors using a 252Cf neutron sourcea)

Cited by 82 publications

References 10 publications

First measurement of time-resolved neutron yield on JT-60U using a microfission chamber

First measurement of time-resolved neutron yield on JT-60U using a microfission chamber

Wide dynamic range neutron flux monitor having fast time response for the Large Helical Device

Neutronic Analysis of Fusion Tokamak Devices by PHITS

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