利用PROSPECT在高通量同位素反应堆（HFIR）测量来自235U裂变的反中微子能谱。

Measurement of the Antineutrino Spectrum from ^{235}U Fission at HFIR with PROSPECT.

作者信息

Ashenfelter J, Balantekin A B, Band H R, Bass C D, Bergeron D E, Berish D, Bowden N S, Brodsky J P, Bryan C D, Cherwinka J J, Classen T, Conant A J, Cox A A, Davee D, Dean D, Deichert G, Diwan M V, Dolinski M J, Erickson A, Febbraro M, Foust B T, Gaison J K, Galindo-Uribarri A, Gilbert C E, Gilje K E, Hackett B T, Hans S, Hansell A B, Heeger K M, Insler J, Jaffe D E, Ji X, Jones D C, Kyzylova O, Lane C E, Langford T J, LaRosa J, Littlejohn B R, Lu X, Martinez Caicedo D A, Matta J T, McKeown R D, Mendenhall M P, Minock J M, Mueller P E, Mumm H P, Napolitano J, Neilson R, Nikkel J A, Norcini D, Nour S, Pushin D A, Qian X, Romero-Romero E, Rosero R, Sarenac D, Surukuchi P T, Telles A B, Tyra M A, Varner R L, Viren B, White C, Wilhelmi J, Wise T, Yeh M, Yen Y-R, Zhang A, Zhang C, Zhang X

机构信息

Wright Laboratory, Department of Physics, Yale University, New Haven, Connecticut 06520, USA.

Department of Physics, University of Wisconsin, Madison, Madison, Wisconsin 53706, USA.

出版信息

Phys Rev Lett. 2019 Jun 28;122(25):251801. doi: 10.1103/PhysRevLett.122.251801.

DOI:10.1103/PhysRevLett.122.251801

PMID:31347897

Abstract

This Letter reports the first measurement of the ^{235}U ν[over ¯]{e} energy spectrum by PROSPECT, the Precision Reactor Oscillation and Spectrum experiment, operating 7.9 m from the 85 MW{th} highly enriched uranium (HEU) High Flux Isotope Reactor. With a surface-based, segmented detector, PROSPECT has observed 31678±304(stat) ν[over ¯]{e}-induced inverse beta decays, the largest sample from HEU fission to date, 99% of which are attributed to ^{235}U. Despite broad agreement, comparison of the Huber ^{235}U model to the measured spectrum produces a χ^{2}/ndf=51.4/31, driven primarily by deviations in two localized energy regions. The measured ^{235}U spectrum shape is consistent with a deviation relative to prediction equal in size to that observed at low-enriched uranium power reactors in the ν[over ¯]{e} energy region of 5-7 MeV.

摘要

本信函报道了“精确反应堆振荡与能谱实验”（PROSPECT）对²³⁵U反中微子（ν̅ₑ）能谱的首次测量，该实验在距85兆瓦热功率高浓铀（HEU）高通量同位素反应堆7.9米处运行。利用基于表面的分段探测器，PROSPECT观测到31678±304（统计）次由ν̅ₑ引发的逆β衰变，这是迄今为止来自高浓铀裂变的最大样本，其中99%归因于²³⁵U。尽管总体相符，但将休伯²³⁵U模型与测量能谱进行比较时，得到的χ²/自由度 = 51.4/31，主要是由两个局部能量区域的偏差所致。测量得到的²³⁵U能谱形状与预测值相比存在偏差，其大小与在低浓铀动力反应堆5 - 7兆电子伏特的ν̅ₑ能量区域所观测到的偏差相当。