Investigation of ortho <-> para hydrogen conversion by collisions with neutrons

doi:10.1080/00223131.2017.1412363

	Investigation of ortho <-> para hydrogen conversion by collisions with neutrons
	Shen F(沈飞); Wang SL(王松林); Hu ZL(胡志良); 周斌(东); Liang TJ(梁天骄); Mei, LW; Liu, C; Shen, F; Wang, SL; Hu, ZL
刊名	JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY
	2018
卷号	55 期号:5 页码:478-483
关键词	MCNP neutron source liquid hydrogen para-ortho hydrogen conversion thermal neutron scattering cryogenic moderator cross section
ISSN号	0022-3131
DOI	10.1080/00223131.2017.1412363
文献子类	Article
英文摘要	Liquid hydrogen (LH) is constituted by para hydrogen (pH) and ortho hydrogen (oH) molecules. We analyzed the neutron scattering cross sections for pHoH, pHpH, oHpH, and oHoH reactions in LH. Results show that incident neutron energy lower than 14.7meV is not sufficient to achieve pHoH conversion. As energy increases, the cross section of pHoH reaction increases sharply. If incident neutron energy is larger than 30 meV, branching fraction of pH molecules being converted into oH molecules upon inelastic scattering with the neutrons approaches 100%. As for the opposite process, branching fraction of oHpH conversion is 10%-20% when incident neutron energy is lower than 30 meV. This conversion fraction oscillates with increasing incident neutron energy, eventually stabilizing at 30%. Based on the cross sections of the four reaction channels, we calculated the corresponding conversion rates based on a reactor cold neutron source model. There is 0.12% pH molecules of LH moderator would be converted to oH for one month operation . If neutron flux increased by 2 orders of magnitude, more than 10% pH would be transformed into oH, which means relative conversion rate of pHoH induced by neutron inelastic scattering is not negligible.
电子版国际标准刊号	1881-1248
WOS关键词	HOMONUCLEAR DIATOMIC LIQUIDS ; SCATTERING ; ROTATION
WOS研究方向	Nuclear Science & Technology
语种	英语
WOS记录号	WOS:000428678300002
内容类型	期刊论文
源URL	[http://ir.ihep.ac.cn/handle/311005/285789]
专题	高能物理研究所_东莞分部高能物理研究所_实验物理中心中国科学院高能物理研究所_中国散裂中子源
通讯作者	Mei LW(梅龙伟)
作者单位	中国科学院高能物理研究所
推荐引用方式 GB/T 7714	Shen F,Wang SL,Hu ZL,et al. Investigation of ortho <-> para hydrogen conversion by collisions with neutrons[J]. JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY,2018,55(5):478-483.
APA	沈飞.,王松林.,胡志良.,周斌.,梁天骄.,...&梅龙伟.(2018).Investigation of ortho <-> para hydrogen conversion by collisions with neutrons.JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY,55(5),478-483.
MLA	沈飞,et al."Investigation of ortho <-> para hydrogen conversion by collisions with neutrons".JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY 55.5(2018):478-483.