Systematic studies on a decay half-lives of neptunium isotopes
You-Tian Zou, Xiao Pan, Hong-Ming Liu, Xi-Jun Wu, Biao He, Xiao‐Hua Li
Abstract
Abstract In the present work, we systematically study the α decay half-lives of neptunium ( Z = 93) isotopes within a one-parameter model (OPM). The calculated results are in reasonable agreement with the experimental data. Noticeably, the recently measured α decay half-life value of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mn>380</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>110</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>260</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> ns for 222 Np [ Phys. Rev. Lett. 125 , 032 502 (2020)] has been fairly reproduced by the OPM as 780 ns within a factor of ≈2. In addition, we extend this model to predict α decay half-lives of neptunium isotopes whose α decay is energetically allowed or observed but not yet quantified in NUBASE2016. Meanwhile, it is found that the half-life between the neutron number N = 126 and N = 128 in Np drop sharply, this result shows that the N = 126 shell closure is still very robust at Z = 93. At last, α particle preformation probability <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mi>P</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>α</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>extd</mml:mi> </mml:mrow> </mml:msubsup> </mml:math> are extracted in two cases with α transition orbital angular momentum l = 0 and l = 1, we find a amazing phenomenon that the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mi>P</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>α</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>extd</mml:mi> </mml:mrow> </mml:msubsup> </mml:math> are basically the same for α transition with the same orbital angular momentum l .