An ionization chamber with fast timing properties was built at CERN for measuring fission crosssections of minor actinides at the n_TOF neutron beam. The design of this new chamber and of the front-end electronics was optimized to match the innovative features of the n_TOF facility, in particular the high instantaneous neutron flux and low background. For the most radioactive isotopes, a special version of the chamber, designed according to the ISO2919 standards, was built in order to comply with the radioprotection requirements at CERN. The detector and front-end electronics are here described, together with the simulated and measured response to fission fragments and a-particles. The performances of the chamber during the first measurement campaign at n_TOF are presented, focusing in particular on the fast time response, the good background rejection capability, low-background and high detection efficiency.

CALVIANI M.;  CENNINI P.;  KARADIMOS D.;  KETLEROV V.;  KONOVALOV V.;  FURMAN W.;  GOVERDOWSKI A.;  VLACHOUDIS V.;  ZANINI L.;  THE N_Tof Collaboration; 

2009-07-27

ELSEVIER SCIENCE BV

JRC47583

0168-9002,   

http://dx.doi.org/10.1016/j.nima.2008.06.006,    https://publications.jrc.ec.europa.eu/repository/handle/JRC47583,   

10.1016/j.nima.2008.06.006,