Pommé S, Stroh H, Van Ammel R
European Commission, Joint Research Centre (JRC), Directorate for Nuclear Safety and Security, Retieseweg 111, B-2440, Geel, Belgium.
European Commission, Joint Research Centre (JRC), Directorate for Nuclear Safety and Security, Retieseweg 111, B-2440, Geel, Belgium.
Appl Radiat Isot. 2019 Jun;148:27-34. doi: 10.1016/j.apradiso.2019.01.008. Epub 2019 Jan 29.
The half-life of Fe has been measured accurately by following the decay curve of three sources with a large pressurised proportional counter. An argon(90%)-methane(10%) mixture was used as counter gas, at atmospheric pressure (∼1 × 10 Pa) and at enhanced pressures of 5 × 10 Pa and 8 × 10 Pa (for 1 source), respectively. The first measurements were performed in 2001, but the experiment was executed more systematically between 2005 and 2018, covering a period of about 5 half-lives. The residuals from an exponential decay curve were of the order of 0.1% to 0.2% at 1 × 10 Pa, and 0.03% at 5 × 10 Pa and 8 × 10 Pa. The gain of stability with increased gas pressure was due to asymptotically reaching the maximum counting efficiency, resulting in lower sensitivity to pressure variations. The deduced half-life value of T(Fe) = 1006.70 (15) d or 2.7563 (4) a is more accurate than other data in literature, which are mutually discrepant. It is consistent with previous measurements at JRC with an X-ray defined solid angle counter.
通过使用大型加压正比计数器跟踪三个源的衰变曲线，精确测量了铁的半衰期。分别在大气压（约1×10帕）以及5×10帕和8×10帕（针对1个源）的增强压力下，使用氩气（90%）-甲烷（10%）混合气体作为计数气体。首次测量于2001年进行，但该实验在2005年至2018年期间进行得更为系统，涵盖了约5个半衰期的时间段。在1×10帕时，指数衰变曲线的残差约为0.1%至0.2%，在5×10帕和8×10帕时为0.03%。随着气压增加稳定性提高是由于渐近达到最大计数效率，从而降低了对压力变化的敏感度。推导出的铁的半衰期值T(Fe)=1006.70(15)天或2.7563(4)年，比文献中相互矛盾的其他数据更为精确。它与之前在联合研究中心使用X射线定义立体角计数器进行的测量结果一致。
