Compact and multi-channel readout system for the long term radioactive waste monitoring.

Poma G.E., Cosentino L., Fanchini E., Finocchiaro P., Garosi P., Longhitano F., Lucchesi A., Ninci D., Simonetto M., Tintori C.
  Martedì 13/09   09:00 - 13:30   Aula L - Christa Mc Auliffe   VI - Fisica applicata, acceleratori e beni culturali   Presentazione
We developed gamma-ray counters (SciFi) and solid-state thermal neutron detectors (SiLiF) as a solution for radioactive waste monitoring. SciFi is a low-cost Geiger counter and consists of scintillating fiber coupled to two silicon photomultipliers (SiPM): thanks to its optimized single-photon sensitivity and left-right coincidence constraint, SciFi can be employed for long-term monitoring. SiLiF detector consists of polyethylene $103 {cm^{3}}$ hollow cube for neutrons thermalization, and double-sided silicon diode placed at its center, sandwiched between two $^{6}LiF$ converter layers: by means of $n+\,$ ^$6$Li\rightarrow \, ^$3$H(2.73 $MeV$)+\, ^$4$He(2.05 ${MeV})$ reaction, we can count the $^{3}H$ and alpha contributions and reconstruct their energy spectra. In order to obtain a compact optimized data acquisition system, a 64-channel digitizer coupled with power supply, and new CAEN Front-End board with dedicated software have been employed for neutron and gamma detection, respectively. By using $\gamma /{n}$ sources, several tests have been carried out in laboratory environments by means of activity known point-like sources and radwaste drums with undefined compositions and activity distributions. Preliminary results will be presented.