出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：Electron screening strongly changes nuclear reaction cross sections at energies below 1000 times
the screening energy Ue. It has been found that Ue can be one order of magnitude larger than
predicted by theory [1] if the target atoms are hosted in a metallic environment. As a consequence,
a change of lifetimes of low-energy b and a emitters may also be considered if they are situated
in a metal. In addition, a temperature dependence of the screening effect has been proposed [2],
dramatically changing some half-lifes if the metal is cooled [3, 5]. We checked these claims
experimentally by measuring the decay rate of 22Na in a piece of aluminum activated by a 70
MeV proton beam. We observed the 22Na activity both at room temperature and when cooled
down to nearly LN2 temperatures. As a result, a 10% increase as proposed by [3] can be clearly
excluded. Furthermore, a 1/pT temperature dependence of Ue as it was proposed by [3, 5] when
the Debye-Hückel model is applied is unlikely.
