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

J Ashenfelter; A B Balantekin; H R Band; C D Bass; D E Bergeron; D Berish; N S Bowden; J P Brodsky; C D Bryan; J J Cherwinka; T Classen; A J Conant; A A Cox; D Davee; D Dean; G Deichert; M V Diwan; M J Dolinski; A Erickson; M Febbraro; B T Foust; J K Gaison; A Galindo-Uribarri; C E Gilbert; K E Gilje; B T Hackett; S Hans; A B Hansell; K M Heeger; J Insler; D E Jaffe; X Ji; D C Jones; O Kyzylova; C E Lane; T J Langford; J LaRosa; B R Littlejohn; X Lu; D A Martinez Caicedo; J T Matta; R D McKeown; M P Mendenhall; J M Minock; P E Mueller; H P Mumm; J Napolitano; R Neilson; J A Nikkel; D Norcini; S Nour; D A Pushin; X Qian; E Romero-Romero; R Rosero; D Sarenac; P T Surukuchi; A B Telles; M A Tyra; R L Varner; B Viren; C White; J Wilhelmi; T Wise; M Yeh; Y-R Yen; A Zhang; C Zhang; X Zhang; PROSPECT Collaboration  <a href="#n3">3</a>

doi:10.1103/PhysRevLett.122.251801

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

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

Authors

J Ashenfelter¹, A B Balantekin², H R Band¹, C D Bass³, D E Bergeron⁴, D Berish⁵, N S Bowden⁶, J P Brodsky⁶, C D Bryan⁷, J J Cherwinka⁸, T Classen⁶, A J Conant⁹, A A Cox¹⁰, D Davee¹¹, D Dean¹², G Deichert⁷, M V Diwan¹³, M J Dolinski¹⁴, A Erickson⁹, M Febbraro¹², B T Foust¹, J K Gaison¹, A Galindo-Uribarri^{12

15}, C E Gilbert^{12

15}, K E Gilje¹⁶, B T Hackett^{12

15}, S Hans¹³, A B Hansell⁵, K M Heeger¹, J Insler¹⁴, D E Jaffe¹³, X Ji¹³, D C Jones⁵, O Kyzylova¹⁴, C E Lane¹⁴, T J Langford¹, J LaRosa⁴, B R Littlejohn¹⁶, X Lu^{12

15}, D A Martinez Caicedo¹⁶, J T Matta¹², R D McKeown¹¹, M P Mendenhall⁶, J M Minock¹⁴, P E Mueller¹², H P Mumm⁴, J Napolitano⁵, R Neilson¹⁴, J A Nikkel¹, D Norcini¹, S Nour⁴, D A Pushin¹⁰, X Qian¹³, E Romero-Romero^{12

15}, R Rosero¹³, D Sarenac¹⁰, P T Surukuchi¹⁶, A B Telles¹, M A Tyra⁴, R L Varner¹², B Viren¹³, C White¹⁶, J Wilhelmi⁵, T Wise¹, M Yeh¹³, Y-R Yen¹⁴, A Zhang¹³, C Zhang¹³, X Zhang¹⁶; PROSPECT Collaboration <a href="#n3">3</a>

Affiliations

¹ Wright Laboratory, Department of Physics, Yale University, New Haven, Connecticut 06520, USA.
² Department of Physics, University of Wisconsin, Madison, Madison, Wisconsin 53706, USA.
³ Department of Physics, Le Moyne College, Syracuse, New York 13214, USA.
⁴ National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA.
⁵ Department of Physics, Temple University, Philadelphia, Pennsylvania 19122, USA.
⁶ Nuclear and Chemical Sciences Division, Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
⁷ High Flux Isotope Reactor, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
⁸ Physical Sciences Laboratory, University of Wisconsin, Madison, Madison, Wisconsin 53706, USA.
⁹ George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
¹⁰ Institute for Quantum Computing and Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
¹¹ Department of Physics, College of William and Mary, Williamsburg, Virginia 23187, USA.
¹² Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
¹³ Brookhaven National Laboratory, Upton, New York 11973, USA.
¹⁴ Department of Physics, Drexel University, Philadelphia, Pennsylvania 19104, USA.
¹⁵ Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37916, USA.
¹⁶ Department of Physics, Illinois Institute of Technology, Chicago, Illinois 60616, USA.

PMID: 31347897
DOI: 10.1103/PhysRevLett.122.251801

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.