Studies of the fast ion confinement in the Large Helical Device by using neutron measurement and integrated codes

The neutral beam (NB) fast ion confinement in the Large Helical Device (LHD) is studied for several full field ( $B_{t}\sim 2.75~\text{T}$ ) magnetic configurations by a combination of neutron measurement and simulations. To investigate the NB fast ion confinement, we have performed a series of short-pulse NB injection experiments. The experiment results are analysed by the integrated code TASK3D-a. From this investigation, the effective particle diffusion coefficients of the tangential and perpendicular NBs are approximately $D^{\text{eff}}\sim 0.1~\text{m}^{2}~\text{s}^{-1}$ and $D^{\text{eff}}\sim 1~\text{m}^{2}~\text{s}^{-1}$ in the standard configuration. It is clarified that the NB fast ion confinement improves when the plasmas are shifted inward. Moreover, it is also found that the simulation, which considers the deuteron dilution effect due to the presence of impurity ions, can describe a neutron emission rate consistent with the measurement.

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Fast Ion Confinement Study by Neutron Emission Rate Measurement after Short Pulse NB Injection in the Large Helical Device

Plasma and Fusion Research ◽

10.1585/pfr.13.3402024 ◽

2018 ◽

Vol 13 (0) ◽

pp. 3402024-3402024 ◽

Cited By ~ 3

Author(s):

Takeo NISHITANI ◽

Kunihiro OGAWA ◽

Neng PU ◽

Hiroki KAWASE ◽

Sadayoshi MURAKAMI ◽

...

Keyword(s):

Emission Rate ◽

Neutron Emission ◽

Short Pulse ◽

Rate Measurement ◽

Fast Ion

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Fast Ion and Neutron Emission in CO2 Laser Irradiation of Solid Deuterium Targets

Laser Interaction and Related Plasma Phenomena ◽

10.1007/978-1-4684-8798-5_4 ◽

1977 ◽

pp. 657-675

Author(s):

J. L. Bocher ◽

J. P. Elie ◽

J. Martineau ◽

M. Rabeau ◽

C. Patou

Keyword(s):

Laser Irradiation ◽

Co2 Laser ◽

Neutron Emission ◽

Solid Deuterium ◽

Fast Ion

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Characterization of the New Vertical Neutron Camera Designed for the Low Neutron Emission Rate Plasma in Large Helical Device

Plasma and Fusion Research ◽

10.1585/pfr.16.1402039 ◽

2021 ◽

Vol 16 (0) ◽

pp. 1402039-1402039

Author(s):

Siriyaporn SANGAROON ◽

Kunihiro OGAWA ◽

Mitsutaka ISOBE ◽

Yutaka FUJIWARA ◽

Hiroyuki YAMAGUCHI ◽

...

Keyword(s):

Emission Rate ◽

Neutron Emission

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ABSOLUTE STANDARDIZATION OF RADIOACTIVE NEUTRON SOURCES: II. THE USE OF THE F19(α, n)Na22 REACTION

Canadian Journal of Physics ◽

10.1139/p59-062 ◽

1959 ◽

Vol 37 (5) ◽

pp. 550-556 ◽

Cited By ~ 7

Author(s):

K. W. Geiger

Keyword(s):

Nuclear Reactions ◽

Emission Rate ◽

Neutron Emission ◽

National Research Council ◽

Neutron Output ◽

Neutron Sources ◽

Neutron Thermalization ◽

Γ Rays ◽

Absolute Standardization ◽

Good Agreement

Fluorine has only one stable isotope, F19. If neutrons are produced by the F19(α, n)Na22 reaction the neutron output can be calculated from the yield of the resulting radioactive Na22. The growth of Na22 (half-life, 2.58 years) has been measured in a neutron source consisting originally of 1.6 curies Po210 mixed with CaF2 powder. Since Na22 is a positron emitter, discrimination against γ-rays from Po210 and from nuclear reactions could be achieved by detecting the two positron annihilation quanta in coincidence. The Na22 growth has been followed over 20 months and is in agreement with the theoretical growth curve. Comparison with a calibrated Na22 source yielded a neutron emission rate of (10.70 ± 0.25) × 104 sec−1. This resulted in a neutron emission rate of (3.16 ± 0.10) × 106 sec−1 for the Ra-α-Be source of the National Research Council, in good agreement with (3.22 ± 0.05) × 106 sec−1 obtained by a neutron thermalization method.

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Pre-saddle and pre-scission neutron emission rates in heavy-ion induced fission of 16O +208Pb and 16O +209Bi systems

International Journal of Modern Physics E ◽

10.1142/s0218301319500137 ◽

2019 ◽

Vol 28 (03) ◽

pp. 1950013

Author(s):

Saeed Soheyli ◽

Morteza Khalil Khalili ◽

Ghazaaleh Ashrafi

Keyword(s):

Emission Rate ◽

Neutron Emission ◽

Nonlinear Behavior ◽

Heavy Ion ◽

Neutron Multiplicity ◽

Emission Rates ◽

Reaction Systems ◽

Initial Excitation ◽

Induced Fission ◽

First Time

Whereas there is a slight information on the pre-saddle neutron emission rate and neutron multiplicity, as well as it is impossible to separate the pre-saddle and saddle to scission neutron contributions experimentally, the theoretical studies of pre-saddle neutron emission rate and neutron multiplicity are of great importance. In the present work, the calculations of pre-saddle neutron multiplicity are performed using the analysis of fission fragment angular anisotropy data for [Formula: see text] and [Formula: see text] reaction systems. The obtained results show that the pre-saddle neutron multiplicity decreases by increasing the initial excitation energy and it has found to be characterized by a nonlinear behavior. Through the analysis of pre-saddle neutron multiplicity and pre-saddle transition time by means of the neutron clock method, the pre-saddle neutron emission rate is calculated for the first time. The findings of this study show that the pre-scission neutron emission rate is lower than the pre-saddle neutron emission rate.

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