# Measurement of gamma-ray dose rate distribution at the Kindai university reactor using the thermoluminescent properties of BeO ceramic plates

## TL;DR

Researchers measured gamma-ray doses at a low-power university reactor using BeO ceramic dosimeters, which are less affected by neutrons.

## Contribution

The study demonstrates the use of low-Na BeO ceramic TLDs as a neutron-insensitive alternative for gamma-ray dosimetry in mixed radiation fields.

## Key findings

- BeO ceramic TLDs showed height-dependent gamma-ray dose rate trends consistent with prior ionization chamber measurements.
- Gamma-ray dose rates measured with BeO TLDs were 10–30% higher than those from ionization chambers.
- The gamma-ray dose rate at the reactor center was approximately 24 cGy h−1.

## Abstract

The gamma-ray dose rate distribution at the Kindai University Reactor (UTR-KINKI) was measured using the thermoluminescent (TL) properties of beryllium oxide (BeO) ceramic plates. The reactor, operating at an extremely low thermal power of 1 W, is widely used for nuclear research, including radiation biology and detector development. In neutron-gamma mixed fields, determining the gamma-ray dose rate accurately is technically challenging due to the neutron sensitivity of conventional dosimeters. In this study, low-Na BeO ceramic thermoluminescence dosimeters (TLDs) were employed to selectively measure gamma-ray dose rates in the irradiation hole of UTR-KINKI, without the need for neutron correction. A comparative assessment was conducted using Na-doped BeO powder TLDs, and thermal neutron flux measurements were performed using a Li-glass scintillator. The results demonstrated that the height-dependent trend of the gamma-ray dose rate distribution was consistent with previous measurements obtained via paired ionization chambers. However, the absolute values of the gamma-ray dose rates measured with the BeO ceramic TLDs were approximately 10–30% higher than those determined by the paired ionization chamber. This discrepancy is likely due to neutron sensitivity considerations in previous studies. The gamma-ray dose rate at the reactor center was evaluated as approximately 24 cGy h−1. This study highlights the applicability of BeO ceramic TLDs for gamma-ray dosimetry in mixed radiation fields, offering a neutron-insensitive alternative for precise dose measurements in reactor environments.