Angular correlations in the prompt neutron emission of spontaneous fission of 252Cf

Neutron angular distributions in spontaneous fission of 252Cf are investigated. The CORA experiment, performed at IPHC Strasbourg, aims at elucidating neutron emission mechanisms in the fission process. The experimental setup is composed of the angle-sensitive twin ionisation chamber CODIS for the detection of fission fragments and the DEMON neutron detector assembly. The development of a simulation toolkit based on GEANT4 and MENATE_R is described, adapted as a strategy to investigate the influence of experimental conditions on the observed properties of neutrons emitted. Besides the kinematic neutron anisotropy in the laboratory system due to neutron evaporation from moving fragments, two additional effects are discussed which may have an influence on the angular distributions of neutrons: scission neutrons and dynamic neutron emission anisotropy in the CM system of fragments due to the spin carried by fragments. A new analysis method is presented to disentangle the dynamic anisotropy from the other effects in an independent way. For the dynamic anisotropy only an upper limit could be found. Results for the angular correlation (n,n) between two evaporated neutrons and the correlation (n,LF) between an evaporated neutron and the Light Fragment direction of flight are reported.

CHIETERA A.;  STUTTGE L.;  GOENNENWEIN F.;  KOPATCH Y.;  MUTTERER M.;  GAGARSKI A.;  GUSEVA I.;  CHERNYSHEVA E;  HAMBSCH Franz-Josef;  HANAPPE F.;  MEZENTSEVAH Z.;  TELEZHNIKOVCH S.; 

2018-09-11

SPRINGER

JRC107874

1434-6001,   

https://publications.jrc.ec.europa.eu/repository/handle/JRC107874,   

10.1140/epja/i2018-12529-y,