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BPS型TE-TE球形空腔电离室在15MeV中子场测量的修正因子
CORRECTION FACTORS OF THE BPS TE-TE SPHERICAL CAVITY IONZATION CHAMBER IN 15 MeV NEUTRON FIELD
【摘要】 我所研制了BPS型TE-TE球形空腔电离室。本工作测量了这些电离室的基本性能。饱和特性的测量结果表明,在60Co光子场中QB/QV与V-2之间,关系是线性的,相关系数极接近于1,由此得出了饱和修正因子。对于15MeV中子和60Co光子确定了自由空气比释动能的壁厚修正因子,各自为(0.6±0.9)·10-2mm-1和(0.49±0.35)·10-2mm-1当射线入射角度范围在0-120°范围时,室响应相对变化对于60Coγ射线不大于0. 5%,而对于15 MeV中子大约为1%。还研究测定了自由空气照射电离室在光子场与中子场中柄散射的影响,测量和计算了用TE气体和空气分别作为工作气体时电离室读数之比值,结果相符。
【Abstract】 The model BPS TE-TE spherical cavity ionization chambers havebeen constructed in Institute of Biophysics,,Academia Sinica. The basic performencesof the chambers have been measured. The results of measurement of the saturationcharacteristics show that the relation between Qs/Qv and V-2 is linear in 60Co pho-ton field and between Is/Iv and V-1 is linear in D +T neutron photon mixed field.The correlation coefficients is extremely close to 1. The saturation correction factorswere obtained. The wall thickness correction factors for determination of free-in-air are (0. 60±0. 88 ) ×10-2 mm-1 and (0. 49± 0. 35 )× 10-2 mm-1 for 15 MeV neutrons and 60Cophotons respectively. The relative change of the response with angle of irradiation isnot larger than 0.5 per cent when incident degrees of the radiation is in the rangeof 0~120°for the 60Co gamma rays but is about one per cent for the 15 MeV neu-trons. The influences of stem scatter and radiation sensitivity of stem were studiedin photon and neutron fields for irradiation free-in-air. The ratios of readings withTE gas and air were measured for TE-gas and calculated with the ratios of CH4,CO2, N2 given by Williams. The values measured and calculated are coincident. Theeffect of TE gas flow rate on the readings of the chamber was observed.
- 【文献出处】 辐射研究与辐射工艺学报 ,Journal of Radiation Research and Radiation Processing , 编辑部邮箱 ,1986年02期
- 【被引频次】1
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