Thermoluminescence fading studies: Implications for long-duration space measurements in Low Earth Orbit

TL;DR

This study investigates the stability of LiF-based thermoluminescence detectors over 1.5 years under space-like conditions, finding minimal fading and no radiation type influence, supporting their use in long-duration space measurements.

Contribution

It provides comprehensive long-term fading data for LiF TLDs under space-relevant conditions, demonstrating their stability for extended space missions.

Findings

TLD response remains stable within 10% over 1.5 years.

No significant difference between gamma-ray and neutron irradiation effects.

Fading is not a major concern for properly annealed LiF TLDs in long-term space applications.

Abstract

Within a 1.5 year comprehensive fading experiment several batches of LiF:Mg,Ti and LiF:Mg,Cu,P thermoluminescence detectors (TLDs) were studied. The TLDs originated from two manufacturers and were processed by three laboratories using different annealing and readout conditions. The TLDs were irradiated with two radiation modalities (gamma-rays and thermal neutrons) and were stored at two temperatures (-17.4C and +18.5C). The goal of the experiment was to verify the stability of TLDs in the context of their application in long-term measurements in space. The results revealed that the response of all TLDs is stable within 10% for the studied temperature range. No influence of the radiation type was found. These results indicate that for the properly oven-annealed LiF TLDs, fading is not a significant problem, even for measuring periods longer than a year.