A semiconductor detector coupled with a neutron converter is a good candidate for neutron detection, especially for its compactness and reliability if compared with other devices, such as ³He tubes, even though its intrinsic efficiency is rather lower. In this paper we show a neutron detector design consisting of a 3 cm × 3 cm silicon pad detector coupled with one or two external ⁶LiF layers, enriched in ⁶Li at 95%, placed in contact with the Si active surfaces. This prototype, first characterized and tested at INFN Laboratori Nazionali del Sud and then at JRC Ispra, was successfully shown to detect thermal neutrons with the expected efficiency and an outstanding gamma rejection capability.

A prototype array of modular sensors for online monitoring of radioactive waste was developed at INFN-LNS. We implemented a new kind of gamma mini-sensor, based on Silicon PhotoMultipliers and scintillating fibers, that behaves like a cheap scintillating Geiger-Muller counter. It can be placed in shape of a fine grid around each single waste drum in a repository. After simulating the counting response of thin scintillating fibers to gamma radiation, we verified our simulation results with measurements using radioactive sources. Front-end electronics and an FPGA-based counting system were developed to handle the field data, also implementing data transmission, a graphical user interface and a data storage system. A test of four sensors in a real radwaste storage site was performed with promising results.

The current scenario of radioactive waste management requires innovative and automated solutions to ensure its effectiveness and safety. In response to this need, the Proximity Imaging System for Sort and Segregate Operations (PI3SO) project was proposed. It is a gamma radiation proximity scanner system for radioactive waste with the primary goal of speeding up some aspects of the waste management cycle while reducing direct human operations. The system will provide proximity imaging for hot-spot finding and spectral analysis for radiological characterization, enabling semiautomatic recognition, sorting and separation of radioactive waste. The core of the proposed scanning system consists of an array of 128 CsI(Tl) scintillators, 1 cm3 size, coupled with silicon photomultipliers (SiPMs), installed on a motorized bridge sliding along a suitable table in order to scan the materials under investigation.

The Silicon Photomultiplier (SiPM) has become a solid playground for many applications requiring compact and well performing photon detectors. In particular, this is true when the detection of few photons with good time resolution is required. In this paper, we show how the SiPM features can be exploited to set up a compact neutron detector. By coupling two SiPMs to an inorganic scintillator strip, one can discriminate between gamma-rays and neutrons and, at the same time, determine the impact position with millimeter accuracy.

The current scenario of radioactive waste management requires innovative and automated solutions to ensure effectiveness and safety. In response to this need, the PI3SO (Proximity Imaging System for Sort and Segregate Operations) project was proposed. It is a gamma radiation proximity scanner system for radioactive waste with the primary goal of speeding up some aspects of the waste management cycle while reducing direct human operations. The system will provide proximity imaging for hot spot finding and spectral analysis for radiological characterization, enabling semiautomatic recognition, sorting and separation of radioactive waste. The core of the proposed scanning system consists of an array of 128 CsI(Tl) scintillators, 1 cm3 size, coupled with silicon photomultipliers (SiPM), installed on a motorized bridge sliding along a suitable table in order to scan the materials under investigation.

Monitoring radioactive waste (radwaste) is a critical aspect of nuclear waste management, ensuring environmental safety and compliance with regulatory standards. A few initiatives, funded by EURATOM within Horizon 2020, focused on long-term repository surveillance, thus enhancing measurement precision, and ensuring traceability of stored radioactive materials. Among the advanced technologies explored for this purpose, scintillating fibers have emerged as promising tools to monitor gamma radiation due to their sensitivity, flexibility, and real-time data acquisition capabilities. Promising as well was the development of solid state ³He-free neutron sensors. These gamma and neutron sensors we developed can monitor both types of highly penetrating radiation from radwaste drums.