Decay Characteristics of Some Short-Lived Nuclides of Low Atomic Number

Abstract

The short-lived activities in Cl-34, K38, Ca-39, Li-8, He-6, and O-15 formed by high energy bremmstrahlung irradiation have been examined, and some improved values for the half-lives of these nuclides are reported. A detailed description of the apparatus and procedure is included, together with a discussion of the weighted least mean square analysis used.

Precision Measurement of theHe6Half-Life and the Weak Axial Current in Nuclei

“…Our result is in good agreement with two of the previous five values [17,37] with precisions of less than 1% but deviates from the three others by up to 8:6 [38][39][40]. Because the possibility of diffusion out of the target was not directly addressed we speculate that this may be the cause of the discrepancy.…”

“…[17,37] and used in compilations ever since. The inset shows the five values with uncertainties below 1% [17,[37][38][39][40] with the dashed red band depicting the value for the 6 He half-life obtained in this Letter. the inset in Fig.…”

“…1 (color online). Compilation of the measured 6 He halflives found in literature [17,[37][38][39][40][41][42]. The dashed blue band shows the half-life adopted in Ref.…”

Precision measurement of the6He half-life and the weak axial current in nuclei

“…[29,33] and used in compilations ever since. The inset shows the five values with uncertainties below 1% [23,29,[31][32][33] with the dashed red band depicting the value for the 6 He half-life obtained in this paper.…”

Branching of transitions in some mirror nuclei

“…Until recently, the direct observation of the decay of mirror nuclei had been done mainly with scintillation counters, which are more easily applied to spectrum analysis for short-lived decays than other methods because they can sample the entire energy range of the spectrum in a short period of time. The most recent investigations of mirror nuclei using scintillation spectrometer analysis of the positron spectra were those of various individuals at the synchrotron laboratory of Iowa State University (6,7,8,9)• Subsequent to the time of these investigations, considerable effort has been spent at the same laboratory to further refine the scintillation technique, the refinements exposing new difficulties im possible to correct up to the time of this report.…”