Suche nach dem Isomer74mAs

An activity with the decay propertiesT _1/2=(8.0±0.3)sec andE _γ=(283±5)keV has been produced bySchardt andGoodman by proton irradiation of thin layers of evaporated⁷³Ge and⁷⁴Ge on thick gold backings. This activity was interpreted as the new isomer^74mAs. In the present experiment a search for^74mAs was carried out using the reactions⁷⁵As(n, 2n),⁷¹Ga(α, n) and⁷⁴Ge(d, 2n).^74mAs could not be detected. Upper limits for the reaction cross sections were determined. It is discussed that the reported properties of^74mAs resemble the known properties of^197mAu.     

Suche nach Zwei-Elektronen-Emission beim Zerfall von113mIn

An electromagnetic transition between two nuclear states may proceed through simultaneous ejection of two atomic electrons. This process was searched for in the decay of^113mIn by means of two lithium-drifted silicon detectors and a two-dimensional pulse height analysis. No evidence for double electron ejection was found. From back-ground analysis, however, upper intensity limits relative to normal singleK-conversion were derived for different modes of the double decay. The intensity of doubleK-electron ejection with electron energies between 68 and 267 keV was determined to be less than 2.0 · 10^?5. This limit was compared with theoretical estimates. In addition, the following limits were obtained: 1.8 · 10^?4 for simultaneous emission of aK- and aL-electron, the energies ranging from 79 to 280 keV, and 2.9 · 10^?5 for simultaneous emission of twoL-electrons with energies between 91 and 292 keV.