Construction of a Portable Mini Luminescence-Measurement System Equipped with a Miniature X-Ray Generator

For the purpose of both luminescence dosimetry and dating, a new portable mini automated luminescence-measuring system has been developed. The main parts of the new system consist of the stimulation unit, an irradiation unit and the photon detector. The size of the main measuring box is approximately 300x300x300 mm. In particular, to keep the electric power as low as possible, a miniature X-ray (Oxford, Eclipse II reflection target) generator and a metal-packaged photomultiplier tube (PMT) (Hamamatsu photonics, H7421-40) were adopted here. 16 blue LEDs were employed for the stimulation of quartz OSL. The same LED holder can be used for pulsed-OSL (P-OSL) measurements. The weight of the main part of this system was about 15 kg.

In order to check the usefulness of the new system, red thermoluminescence (RTL) glow curves were measured to estimate the signal-to-noise ratio (S/N ratio) using a volcanic quartz sample. These results show that the new system improves the S/N ratio in comparison with an existing handmade system. The estimated RTL equivalent (or paleo) dose using quartz extracted from an archaeological roof tile of Shin-Yakushiji temple by means of the SAR protocol was in good agreement with previous measurements. This proves that the new system is suitable for practical use for RTL-measurements either for dosimetry or for dating with a high S/N ratio.