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本文报道了用准直细束照射圆柱形及球形电离室的实验,室壁材料为石蜡、石墨与黄铜,实验结果可以直接用于球形室的反平方律改正。证明了对球形室的改正系数不可能包含距离的奇次项。实验结果表明只考虑与入射方向无关的、正比于被照射面积并且角分布服从余弦律的次级电子成分是不符合实际情况的。提出了一个把次级电子近似地分成两个成分的计算方法,它在射线射入角等于射出角时与实验结果符合的很好,但与已有的前后壁贡献比的实验结果相比还存在着矛盾。所增加的成分虽然也是由室壁产生的,但其反平方律改正,却具有体积积分的形式,因此可以利用已有的反平方律改正的计算结果。这两种成分之比与室壁材料对次级电子的散射能力有关,所以不同材料的反平方律改正系数也将不同。对反平方律改正也作了一般性的讨论。文中还讨论了收集极的作用。
In this paper, we report the experiments of cylindrical and spherical ionization chambers with collimated beamlets. The material of the wall is paraffin, graphite and brass. The experimental results can be directly used to correct the square of the spherical chamber. It is proved that the correction factor for the spherical chamber can not contain the odd term of the distance. Experimental results show that it is unrealistic to consider only the secondary electron components which are independent of the incident direction and proportional to the irradiated area and whose angular distribution obeys the cosine law. A calculation method of approximately subdividing the secondary electrons into two components is proposed, which is in good agreement with the experimental results when the angle of incidence of the radiation is equal to the angle of incidence. However, compared with the experimental results of the contribution ratio There is a contradiction. Although the added components are also produced by the wall of the chamber, the square law of the square is corrected, but it has the form of volume integral. Therefore, the existing square-law-corrected calculation can be used. The ratio of the two components is related to the scattering ability of the wall material to the secondary electrons, so the correction factors for the anti-square law of the different materials will also be different. A general discussion of the anti-square-law correction was also made. The paper also discusses the role of collectors.