Subjects: Nuclear Science and Technology >> Radiation Physics and Technology submitted time 2024-05-01
Hua Leiming
Lu Fei
Su Jun
Shen Yangping
Jin Shilun
Yang Guochun
Li Zhihong
Guo Bing
Liu Longxiang
Cao Xiguang
Abstract： The 𝛽-Oslo experimental method provides an important investigative tool for examining the properties of radioactive nuclides in highly excited states and exploring the nucleosynthesis process for elements ranging from iron to uranium. This paper introduces a novel data processing technique designed to eliminate the impact of 𝛽-decay electrons on the detection of nuclear 𝛾 de-excitation within 𝛽-Oslo experiments, accurately unfolding the observed 𝛾-ray spectra. Utilizing a comprehensive detector response function matrix for 𝛾 rays and decay electrons, this method combines column-pivotal elimination and iterative step-by-step inverse solution approaches to determine the true incident 𝛾 spectrum. The reliability and validity of the proposed method have been substantiated through extensive simulations and inverse calculations.
Subjects: Nuclear Science and Technology >> Radiation Physics and Technology submitted time 2024-04-10
LIN Shen
SONG Luyang
SU Jun
CHEN Xin
SHEN Zhilin
ZHANG Hao
SHENG Yaode
ZHANG Liyong
HE Jianjun
CHEN Size
SHEN Yangping
JIN Shilun
LU Fei
XIAO Dan
ZHANG Yong
NAN Wei
JIANG Yuchen
ZHANG Yuqiang
ZHANG Yang
TIAN Junwen
Abstract： In thermonuclear reactions of nuclear astrophysical interest, some can produce short-lived products that emit positrons. The positrons emitted by these products will annihilate with electrons in the target and then produce a pair of 511 keV γ-rays, which can be used to determine the reaction yield and calculate the cross-section as well as the astrophysical S-factor. Recently, it has been found that the spatial coincidence measurements can be performed basing on the opposite direction of the 511 keV-511 keV γ-ray pair, which can reduce the natural background and enables the in situ measurement of the reaction yield using activity method. In this paper, based on the recently developed large modular BGO detector array LAMBDA-II, this method has been investigated and validated in the ground laboratory, which provides good basis for further application of this method in the nuclear astrophysical investigations in the future.
Peer Review Status:
Awaiting Review
Subjects: Physics >> Nuclear Physics submitted time 2024-01-09
J. Hu
Z.Y. Han
Y.J. Li
Z.H. Li
G. Lian
Y.P. Shen
S.Q. Yan
S. Zeng
B. Guo
W.P. Liu
Z. Bai
B.L. Jia
S.L. Jin
J.B. Ma
P. Ma
S.B. Ma
S.W. Xu
Y.Y. Yang
N.T. Zhang
X.D. Tang
Abstract： In Orgueil meteorites, an exceptionally high 22Ne/20Ne abundance ratio or even nearly pure 22Ne is ob#2;served, which is the so-called Ne extraordinary problem. Fossil material of extinct 22Na is believed to be the origin of extraordinary 22Ne, these 22Na nuclides were trapped in grains and incorporated into meteorites in stellar explo#2;sive event. Supernovae and neon-rich novae are the primary events, which are responsible for the production of 22Na through the explosive hydrogen burning process. 22Na(p, γ)23Mg and 19Ne(α, p) 22Na are two crucial reactions in the so-called NeNa-MgAl cycle and the rapid-proton process, which lead to the fast nucleosynthesis up to A=100 nuclide region and the outburst of novae and X-ray bursters. Since many proton resonance levels in odd-A compound nucleus 23Mg may be involved at nova temperature, existing measurements can only provide partial effective information on the 22Na(p, γ)23Mg reaction. Large uncertainties still exist in the astrophysical reaction rates of the two reactions at present. Thick target inverse kinematics method is a very effective way to scan the 23Mg proton resonance levels re#2;lated to the 22Na(p, γ)23Mg reaction via the excitation function of 22Na(p, p) elastic scattering, which could be obtained over a large energy range in one-shot measurement with low-intensity radioactive 22Na beam. In the present work, 22Na+p resonance scattering via thick target inverse kinematics was studied at RIBLL1 radioactive beam line in the HIRFL national laboratory at Lanzhou. A high-purity 22Na beam with an intensity of about 2 × 105 pps was produced via the 1H(22Ne,22Na)n reaction with an alcohol-cooled hydrogen gas target. Time-of-Flight by two plastic scintillator detectors and two parallel-plate avalanche counters were used to monitor the 22Na secondary beam before reaching the (CH2 )n target. The timing information is useful for beam particle identification and the position information is essen#2;tial for 22Na(p,p) elastic scattering kinematics reconstruction. Light recoil particles from 22Na+p reaction system were detected by two sets of double-sided silicon strip detector telescopes centered at 𝜃lab = 0° and 14°, respectively, while the heavy recoil particles were stopped in the (CH2 )n thick target. Two-body kinematics reconstruction of 22Na(p,p) elastic scattering is performed on the event-by-event basis, and an excitation function of 22Na(p,p) is obtained in the energy range of 𝐸c.m. = 1.5 to 4 MeV. Obvious proton resonance structure is observed in the 23Mg compound nucleus, which will be further analyzed with R-matrix nuclear theoretical model.
Subjects: Physics >> Nuclear Physics submitted time 2023-09-04 Cooperative journals: 《核技术》
Abstract： The first radioactive ion beam line, GIRAFFE, has been built at the CIAE HI-13 tandem accelerator in China. A total of eleven types of radioactive ion beam, including 6He, 7Be, and 8Li, have been generated. Several significant reactions in nuclear astrophysics have been indirectly measured via transfer reactions, and research on nuclear structure, relevant to nuclear astrophysics, has been performed using charge exchange reactions and thick-target experimental methods. A series of single nucleon or α cluster transfer reactions have been measured using a Q3D magnetic spectrometer, and the astrophysical S-factors and reaction rates for essential reactions have been obtained. The obtained results serve as a crucial experimental foundation for research involving element abundance and celestial body models.
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