High precision measurement of the half-life of the 391.6 keV metastable level in 239Pu

被引：0

作者：

Barresi, A. ^{[1
,2
]}

Chiesa, D. ^{[1
,2
]}

Nastasi, M. ^{[1
,2
]}

Previtali, E. ^{[1
,2
,3
]}

Sisti, M. ^{[2
]}

机构：

[1] Univ Milano Bicocca, Dept Phys, I-20126 Milan, Italy

[2] Ist Nazl Fis Nucl, I-20126 Milan, Italy

[3] Ist Nazl Fis Nucl, Lab Nazl Gran Sasso, I-67100 Laquila, Italy

来源：

PHYSICAL REVIEW C | 2022年 / 105卷 / 03期

关键词：

SPECTRUM; NP-239;

D O I：

10.1103/PhysRevC.105.034346

中图分类号：

O57 [原子核物理学、高能物理学];

学科分类号：

070202 ;

摘要：

Materials selection for rare event physics requires high performance detectors and customized analyses. In this context a novel beta-gamma detection system, composed of a liquid scintillator in coincidence with a high-purity germanium (HPGe) detector, was developed with the main purpose of studying ultratrace contamination of uranium, thorium, and potassium in liquid samples. In the search for U-238 contaminations through neutron activation analysis, since the activation product Np-239 decays to a relatively long-lived isomeric state of Pu-239, it is possible to perform a time selection of these events, obtaining a strong background suppression. Investigating the time distribution of the coincidences between the beta(-) decay of Np-239 and the delayed events following the deexcitation of the Pu-239 isomeric level at 391.6 keV, a precision measurement of the half-life of this level was conducted. The resulting half-life of the 391.6 keV Pu-239 level is 190.2 +/- 0.2 ns, thus increasing the precision by about a factor of 20 over previous measurements.

引用

页数：5