Differential Study of ²⁵²Cf(sf) Neutron Emission

Abstract

The double-differential probability N(E, θ) of ²⁵²Cf(sf) neutron emission (E - ls neutron energy,

θ - ls angle of neutron emission with reference to light-fragment direction) was measured by the use of two parallel plate avalanche counters (one position-sensitive) for fragment detection (time of flight, direction) as well as two NE213 scintillators for neutron detection (time-of-flight, scintillator response).

The angular resolution amounts to 3°. The N(E,θ) data cover the full angle range from 0 to 180° by steps of 1.5°. Preliminary results are compared with calculations performed in the framework of the complex cascade evaporation model, i.e. evaporation from fully accelerated fragments is considered as alone emission mechanism. A N(E,8) valley appearing at θ→0° and close to E_f (fragment kinetic energy per nucleon) is explained as a kinematic effect which was reproduced in the calculations.

Specifically measured distributions are much more anisotropic than previous data at high energy.