在-196℃装有液氮罐里由~(60)Coγ射线辐照作物种子,由 TLD 监测,测出液氮对γ射线的减弱常数,然后由减弱常数计算出作物种子的吸收剂量,同时通过液氮线性减系数计算,验证由 TLD 监测所得到的结果,两者相差不超过5%。文中还对 CaSO_4:Dy 和 LiF 两种 TLD 在极低温度下与常温下的热释发光响应进行了比较。 The crop seeds were irradiated with ~ (60) Coγ-rays in a liquid nitrogen tank at -196 ℃ and monitored by TLD to measure the attenuation constant of γ-rays by liquid nitrogen. Then, the absorbed dose of crop seeds was calculated from the attenuation constant, The liquid nitrogen reduction factor is calculated to verify the results obtained from TLD monitoring with a difference of less than 5%. In the paper, the thermoluminescence response of CaSO_4: Dy and LiF at very low temperature was also compared.