Measurements of the change of neutronic performance of a hydrogen moderator at Manuel Lujan Neutron Scattering Center due to conversion from ortho- to para-hydrogen state

M. Ooi; T. Ino; G. Muhrer; E. J. Pitcher; G. J. Russell; P. D. Ferguson; E. B. Iverson; D. Freeman; Y. Kiyanagi

doi:10.1016/j.nima.2006.06.073

Measurements of the change of neutronic performance of a hydrogen moderator at Manuel Lujan Neutron Scattering Center due to conversion from ortho- to para-hydrogen state

M. Ooi, T. Ino, G. Muhrer, E. J. Pitcher, G. J. Russell, P. D. Ferguson, E. B. Iverson, D. Freeman, Y. Kiyanagi

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15 Scopus citations

Abstract

The ortho/para-hydrogen ratio is a key parameter for the neutronic performance of a liquid hydrogen moderator. In order to get a better understanding of the influence that the ortho/para-hydrogen ratio has on the performance of such a moderator, we measured the neutronic performance of the partially coupled liquid-hydrogen moderator at the LANSCE Manuel Lujan Jr. Neutron Scattering Center, Los Alamos, USA, as a function of time after condensation. This was done by measuring the energy spectra and pulse shapes (neutron emission time distributions) of this moderator. It was found that the neutronic characteristic of the moderator changes with the elapsed time after condensation, and that the changes were so significant that for any scattering experiment made on such a moderator, the effect should be carefully evaluated.

Original language	English
Pages (from-to)	699-705
Number of pages	7
Journal	Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Volume	566
Issue number	2
DOIs	https://doi.org/10.1016/j.nima.2006.06.073
State	Published - Oct 15 2006

Funding

This work was supported by the Program of Collaborative Research and Development by KEK. We would like to thank the SPEAR instrument scientists for their assistance.

Funders	Funder number
High Energy Accelerator Research Organization

Keywords

Emission time distribution
Energy spectrum
Hydrogen moderator
Ortho-para conversion
Pulsed neutron source

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10.1016/j.nima.2006.06.073

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Ooi, M., Ino, T., Muhrer, G., Pitcher, E. J., Russell, G. J., Ferguson, P. D., Iverson, E. B., Freeman, D., & Kiyanagi, Y. (2006). Measurements of the change of neutronic performance of a hydrogen moderator at Manuel Lujan Neutron Scattering Center due to conversion from ortho- to para-hydrogen state. Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 566(2), 699-705. https://doi.org/10.1016/j.nima.2006.06.073

Ooi, M. ; Ino, T. ; Muhrer, G. et al. / Measurements of the change of neutronic performance of a hydrogen moderator at Manuel Lujan Neutron Scattering Center due to conversion from ortho- to para-hydrogen state. In: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 2006 ; Vol. 566, No. 2. pp. 699-705.

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Ooi, M, Ino, T, Muhrer, G, Pitcher, EJ, Russell, GJ, Ferguson, PD , Iverson, EB, Freeman, D & Kiyanagi, Y 2006, 'Measurements of the change of neutronic performance of a hydrogen moderator at Manuel Lujan Neutron Scattering Center due to conversion from ortho- to para-hydrogen state', Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, vol. 566, no. 2, pp. 699-705. https://doi.org/10.1016/j.nima.2006.06.073

Measurements of the change of neutronic performance of a hydrogen moderator at Manuel Lujan Neutron Scattering Center due to conversion from ortho- to para-hydrogen state. / Ooi, M.; Ino, T.; Muhrer, G. et al.
In: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 566, No. 2, 15.10.2006, p. 699-705.

Research output: Contribution to journal › Article › peer-review

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Ooi M, Ino T, Muhrer G, Pitcher EJ, Russell GJ, Ferguson PD et al. Measurements of the change of neutronic performance of a hydrogen moderator at Manuel Lujan Neutron Scattering Center due to conversion from ortho- to para-hydrogen state. Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 2006 Oct 15;566(2):699-705. doi: 10.1016/j.nima.2006.06.073

Measurements of the change of neutronic performance of a hydrogen moderator at Manuel Lujan Neutron Scattering Center due to conversion from ortho- to para-hydrogen state

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