Energy per ion pair measurements in pure helium and helium mixtures.
Energy per ion pair measurements in pure helium and helium mixtures.
复制标题
纯氦和氦混合物中每个离子对的能量测量。
DOI：
10.2307/3574351
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发表时间：
1976
影响因子：
3.4
通讯作者：
C. Doust
中科院分区：
文献类型：
--
作者：
S. Harris;C. Doust
在许多已发表的反W（产生氦离子对的平均能量）的测量结果之间存在着不一致。由于其他气体的结果相对一致，差异的原因通常归因于需要使用超纯氦以避免潘宁电离。这是由与污染物原子碰撞导致的高激发亚稳态的去激发引起的。对于在纯氦中完全停止的/sup 241/Am α粒子，反W的新实验值为43.5 ± 0.3eV/离子对。特别注意了纯氦的建立和维持。目前的结果与修正分子离子形成的理论预测吻合得很好。气体混合物的研究表明，氦的非亚稳态激发态是部分负责潘宁电离效应，以前归因于亚稳态单独。
Discrepancies exist between the many published measurements of anti W, the average energy to produce an ion pair for helium. Since results for other gases have been relatively consistent, the cause of the discrepancies usually has been attributed to the need to use ultrapure helium in order to avoid Penning ionization. This arises from the deexcitation of highly excited metastable states by collisions with contaminant atoms. A new experimental value of anti W has been established as 43.5 +- 0.3 eV per ion pair for /sup 241/Am alpha particles completely stopped in purified helium. Particular attention has been paid to the establishment and maintenance of pure helium. The present result agrees well with theoretical predictions corrected for molecular ion formation. Gas mixture studies have been made which indicate that nonmetastable excited states of helium are responsible in part for the Penning ionization effect, previously attributed to metastable states alone.