Theory of Bremsstrahlung and Pair Production. II. Integral Cross Section for Pair Production
Theory of Bremsstrahlung and Pair Production. II. Integral Cross Section for Pair Production
复制标题
DOI：
10.1103/physrev.93.788
复制
发表时间：
1954-02
期刊：
影响因子：
--
通讯作者：
H. Davies;H. Bethe;L. Maximon
中科院分区：
文献类型：
--
作者：
H. Davies;H. Bethe;L. Maximon
对Bethe和Maximon在前文中得到的高能韧致辐射和对产生的微分截面进行了全角度积分，给出了全Z的积分截面公式。对于小Z，对Born近似的修正与Z2成正比，并给出了比例常数。对较重元素的修正比Z2定律显示的要小一些。结果表明，修正只与核的大反冲动量有关，而屏蔽只对小反冲动量是重要的，因此，同样的修正也适用于完全、不完全或没有屏蔽的情况。在88 MeV和280 MeV，这些新的预言与对产生截面的观测结果符合得很好，在17.6 MeV也不是不合理的。
The differential cross section for bremsstrahlung and pair production at high energies obtained in the preceding paper by Bethe and Maximon has been integrated over all angles, and formulas are given for the integral cross section for all Z. For small Z, the correction to the Born approximation is proportional to Z 2, and the constant of proportionality is given. The correction for heavier elements is somewhat less than the Z 2 law would indicate. It is shown that the correction is associated only with large recoil momenta of the nucleus whereas screening is important only for small recoil momenta; and, therefore, the same correction is valid in the case of complete, incomplete, or no screening. Agreement of these new predictions with observations of pair-production cross section at 88 and 280 Mev is excellent and not unreasonable at 17.6 Mev.