Optimal design of a CsI(Tl) crystal in a SiPM based compact radiation sensor

The Gamma and Neutron Sensor System for Rapid Dose Rate Mapping in the CLEANDEM Project

The decommissioning of nuclear installations, as well as the possible necessary accident remediations, requires the physical presence of human operators in potentially radiologically hostile environments. The number of active nuclear reactors worldwide is greater than 400, and most of them are 40 to 50 years old, thus implying that soon they will have to be dismantled. In the framework of the H2020 CLEANDEM project, a small robotic vehicle is being developed that is equipped with a series of different sensors for areas that are significantly contaminated by radiation. In this work, we describe the MiniRadMeter system, a compact low-cost sensor capable of being used to perform quick gamma and neutron radiation field mapping of environments prior to the possible start of human operations. The miniature gamma sensor is a 1 cm³ scintillator counter with moderate spectroscopic features read out by means of a 6 × 6 mm² SiPM, whereas neutrons are detected by means of a silicon diode coupled to a layer of ⁶LiF and placed inside a 6 × 6 × 6 cm³ polyethylene box. The front-end and data acquisition electronics were developed based on a Raspberry Pi4 microcomputer. In this paper, the system performance and the preliminary test results are described.

A TECHNOLOGY OVERVIEW OF ACTIVE IONIZING RADIATION DOSEMETERS FOR PHOTON FIELDS

Radiation protection and radiation dosimetry strongly rely on measurements performed by dosimetry instrumentation. Two categories of dosimetry instrumentation prevail: personal dosemeters and survey meters. Passive dosemeters were for many years the base of personal and area dosimetry (environmental, including workplace). Survey meters have been long-established between area meters due to their dose rate measurement capability, but just over a decade ago, debates over possibility that electronic personal dosemeters (EPDs) could replace passive personal dosemeters as legal monitoring devices have started. These debates have now branched into the use of EPDs, but also survey meters in various exposure scenarios, where some concerns have been reported. These concerns were mostly related to the response in pulsed X-ray fields and poor energy response. This article summarizes recent literature related to electronic dosemeters for strongly penetrating photon radiation and covers technologies used in contemporary EPDs and survey meters, their performance and future perspectives.