中子组织当量液的研制及其与水在模体实验中对^(24)Na感生量的比较

Development of the Liquid Tissue-equivalent Material Used for Neutron Experiments and Comparison of ^(24)Na Activated to Water in the Phantom Irradiated by Neutrons.

目的 研制可用于中子实验的液体组织当量材料 ,并检验其在拟人模体中子照射实验中测量2 4Na活度浓度的适用性。方法 根据ICRP 2 3号出版物对人体软组织H、N、O、C四个元素的比例和密度要求 ,以及其他对实验的适用性要求 ,对 180 0 0余种化学物进行筛选、分析、计算和试验。结果 研制了由下列材料和比例 ( % )组成的软组织替代物 :水∶乙醇∶柠檬酸一水∶N -甲基乙酰苯胺∶甘氨酸∶尿素 =5 0 .3∶2 7.5∶8.5 2∶5 .68∶6.4∶1.6。在该组织替代物中 ,四个元素的重量比 ( % )为H∶N∶O∶C =10 .6∶2 .5∶63 .2∶2 3 .7,密度为 1.0 0 6～ 1.0 0 8g/cm3 ( 2 0℃ )。实验表明 ,当组织当量液被水替代时受2 52 Cf中子照射后模体内2 4Na的活度浓度及长方体内活化的2 4Na的分布都有较大差异。结论 大量实际使用表明 :该软组织替代物可方便地适用于人体模中子实验 。

Objective To develop a liquid tissue substitute used for neutron experiments and test its applicability for measurement of specific activities of 24Na in anthropomorphic phantom irradiated by neutrons. Methods In accordance with the ratios of H,N,O and C and the density for soft tissue by ICRP Publication 23 and with other requirements suitable for experiments, more than 18,000 raw chemical substances were screened, analyzed, calculated and tested to prepare the liquid tissue-equivalent substitute. Results The liquid tissue-equivalent substitute has been developed, which made from water,Ethanol, Citric acid monohydrate, N-Methylacetanilide, Glycine and Urea, and their ratios (%) were 50.3∶27.5∶8.52∶5.68∶6.4∶1.6. The weight ratios of H,N,O and C in the substitute equal to 10.6∶2.5∶63.2∶23.7,and its density 1.006 ～1.008g/cm 3(20℃). Experimental results showed that the differences for the specific activities of 24Na in the phantom and for the distribution of activated 24Na in the cuboid after neutron irradiation were very obvious when the tissue substitute replaced by water. Conclusion The liquid tissue-equivalent material can conveniently be applied to neutron experiments and can't be replaced by water, which were proved by a lot of our practical applications.