2023-05-23 オークリッジ国立研究所(ORNL)
◆今回の研究は、核反応を理解するための独自のガスジェットターゲットシステムを使用し、地球と宇宙で同じ物理学を持つ核反応を解明することを目指しています。これにより、人間や惑星などの元素の宇宙的な生成プロセスが明らかになります。
＜関連情報＞
- https://www.ornl.gov/news/element-creation-lab-deepens-understanding-neutron-stars
- https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.130.212701
加速器型中性子星における水素とヘリウムの混合燃焼の34Ar(α,p)37K反応断面積を制約する最初の直接測定結果 First Direct Measurement Constraining the 34Ar(α,p)37K Reaction Cross Section for Mixed Hydrogen and Helium Burning in Accreting Neutron Stars
J. Browne et al. (JENSA Collaboration)
Physical Review Letters Published 22 May 2023
DOI:https://doi.org/10.1103/PhysRevLett.130.212701
ABSTRACT
The rate of the final step in the astrophysical αp process, the 34Ar(α,p)37K reaction, suffers from large uncertainties due to a lack of experimental data, despite having a considerable impact on the observable light curves of x-ray bursts and the composition of the ashes of hydrogen and helium burning on accreting neutron stars. We present the first direct measurement constraining the 34Ar(α,p)37K reaction cross section, using the Jet Experiments in Nuclear Structure and Astrophysics gas jet target. The combined cross section for the 34Ar,Cl(α,p)37K,Ar reaction is found to agree well with Hauser-Feshbach predictions. The 34Ar(α,2p)36Ar cross section, which can be exclusively attributed to the 34Ar beam component, also agrees to within the typical uncertainties quoted for statistical models. This indicates the applicability of the statistical model for predicting astrophysical (α,p) reaction rates in this part of the αp process, in contrast to earlier findings from indirect reaction studies indicating orders-of-magnitude discrepancies. This removes a significant uncertainty in models of hydrogen and helium burning on accreting neutron stars.
