VERDI - a Double (v, E) Fission-Fragment Spectrometer

The investigation of neutron-induced fission characteristics, like fragment mass- and energy-distributions, is usually based on the double-energy technique using twin Frisch-grid ionisation chambers (IC). The main feature of an IC is its insensitivity to radiation damage, which makes it most suitable for measurements in a strong neutron environment. Providing the existence of prompt neutron emission data, the pre-neutron fission fragment mass and energy distributions may be obtained in an iterative process. However, those input data do exist only for the main isotopes of uranium and plutonium with sufficient precision and extrapolation methods have to be applied when analysing neighbouring compound nuclear systems. With the construction of the double (v, E) spectrometer VERDI we aim at the measuring pre- and post-neutron masses directly and simultaneously, avoiding prompt neutron corrections. In order to achieve a mass resolving power A/Delta(A)>100 ultra-fast time pick-up detectors based on artificial diamond material are under investigation. From the simultaneous measurement of pre- and post-neutron fission-fragment data prompt neutron multiplicity may then be inferred as a function of fragment mass and total kinetic energy. In its final state VERDI is supposed to be coupled to particle detectors to measure delayed decay channels from fission fragments as for example beta-delayed neutron emission.

OBERSTEDT Stephan;  BORCEA Ruxandra;  GAMBONI Thierry;  GEERTS Wouter;  HAMBSCH Franz-Josef;  JAIME TORNIN R.;  OBERSTEDT Andreas;  VIDALI Marzio; 

2011-01-26

Institute of Isotopes, Hungarian Academy of Sciences

JRC62788

https://publications.jrc.ec.europa.eu/repository/handle/JRC62788,