Ca2SiO4를 모체로 한 열형광체에도 활성제로 La를 0.1 wt.%, 0.3 wt.%, 0.5 wt.%, 1.0 wt.%의 농도로 첨가하여 1000℃의 질소 분위기의 전기로에서 90분 동안 소결한 후 입자의 크기를 100 ㎛로 일정하게 선별한 후 측정에 사용하 였다. 저에너지 X-선을 조사한 후 측정한 경우 0.1 wt.%에서 상대적으로 열형광 강도가 크게 나타났다. peak shape 법으로 구한 활성화 에너지는 0.434 ～ 0.516 eV이며, 주파수 인자는 0.5 ～ 0.56으로 2차 발광이었다. 자외선을 조사 한 후 측정한 경우 0.3 wt.%에서 상대적인 열형광 강도가 크게 나타났고, 활성화 에너지는 0.415 ～ 0.477 eV이며, 주파수 인자는 0.5 ～ 0.53 으로 2차 발광이었다. 저에너지 방사선에 대한 방사선량과 열형광 강도는 선형적임을 나타 내어 열형광선량계로서 좋은 특성을 나타내고 있다. 본 연구에서 제작한 CaB4O7, Ca2SiO4 열형광체는 저에너지 영역의 방사선에 대하여 우수한 열형광 특성을 가짐을 알 수 있었고, 향후 선량계의 제작에 좋은 물질이 될 것으로 생각한다.

The Ca2SiO4 phosphors doped by La with 0.1 wt%, 0.3 wt%, 0.5 wt%, and 1.0 wt% concentration were prepared by sintering at 1000℃ for 90 minutes in N2 atmosphere. The phosphors were ground in powdered form and were grouped in 100 ㎛ size, then the samples had been exposed to low energy X-ray and UV light. The TL glow curves were measured by heating the phosphors at 10℃/s rate. There was no significantly meaningful correlation between the TL intensity and the doping level. The intensities of the TL peak measured from X-ray irradiated samples doped with 0.1 wt% were relatively strong. The activation energy and the frequency factor were 0.434 ~ 0.516 eV and 0.5 ~ 0.56, respectively. The intensities of the TL peak measured from UV irradiated samples doped with 0.3 wt% were relatively strong. The activation energy and frequency factor were 0.415 ~ 0.477 eV and 0.5 ~ 0.53, respectively. The TL process were found to be the 2nd order for both X-ray and UV irradiation. The TL intensity was increased linearly with the increase of the radiation dose. In summary, the Ca2SiO4 phosphors developed in this study showed good TL characteristics at low energy X-ray and UV light. We believe they will be used as TLDs in near future for personal and environmental radiation detection dosimetry

• 김청미(경남대학교 정보통신학과) | Choungmi Kim
• 서미경(마산대학 방사선과) | Mikyong Seo Corresponding Author