Experimental Evidence of a Variant Neutron Spectrum from the T(t,2n)α Reaction at Center-of-Mass Energies in the Range of 16-50 keV

M Gatu Johnson; C J Forrest; D B Sayre; A Bacher; J-L Bourgade; C R Brune; J A Caggiano; D T Casey; J A Frenje; V Yu Glebov; G M Hale; R Hatarik; H W Herrmann; R Janezic; Y H Kim; J P Knauer; O Landoas; D P McNabb; M W Paris; R D Petrasso; J E Pino; S Quaglioni; B Rosse; J Sanchez; T C Sangster; H Sio; W Shmayda; C Stoeckl; I Thompson; A B Zylstra

doi:10.1103/PhysRevLett.121.042501

Experimental Evidence of a Variant Neutron Spectrum from the T(t,2n)α Reaction at Center-of-Mass Energies in the Range of 16-50 keV

Phys Rev Lett. 2018 Jul 27;121(4):042501. doi: 10.1103/PhysRevLett.121.042501.

Authors

M Gatu Johnson¹, C J Forrest², D B Sayre³, A Bacher⁴, J-L Bourgade⁵, C R Brune⁶, J A Caggiano³, D T Casey³, J A Frenje¹, V Yu Glebov², G M Hale⁷, R Hatarik³, H W Herrmann⁷, R Janezic², Y H Kim⁷, J P Knauer², O Landoas⁵, D P McNabb³, M W Paris⁷, R D Petrasso¹, J E Pino³, S Quaglioni³, B Rosse⁵, J Sanchez³, T C Sangster², H Sio¹, W Shmayda², C Stoeckl², I Thompson³, A B Zylstra⁷

Affiliations

¹ Massachusetts Institute of Technology Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA.
² Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA.
³ Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
⁴ Indiana University, Bloomington, Indiana 47405, USA.
⁵ CEA, DAM, DIF, F-91297 Arpajon, France.
⁶ Ohio University, Athens, Ohio 45701, USA.
⁷ Los Alamos National Laboratory, Los Alamos, New Mexico 87544, USA.

PMID: 30095940
DOI: 10.1103/PhysRevLett.121.042501

Abstract

Full calculations of six-nucleon reactions with a three-body final state have been elusive and a long-standing issue. We present neutron spectra from the T(t,2n)α (TT) reaction measured in inertial confinement fusion experiments at the OMEGA laser facility at ion temperatures from 4 to 18 keV, corresponding to center-of-mass energies (E_{c.m.}) from 16 to 50 keV. A clear difference in the shape of the TT-neutron spectrum is observed between the two E_{c.m.}, with the ^{5}He ground state resonant peak at 8.6 MeV being significantly stronger at the higher than at the lower energy. The data provide the first conclusive evidence of a variant TT-neutron spectrum in this E_{c.m.} range. In contrast to earlier available data, this indicates a reaction mechanism that must involve resonances and/or higher angular momenta than L=0. This finding provides an important experimental constraint on theoretical efforts that explore this and complementary six-nucleon systems, such as the solar ^{3}He(^{3}He,2p)α reaction.