分类： 物理学 >> 核物理学 提交时间： 2024-03-19
摘要： In recent years, the gap between the supply and demand of medical radioisotopes has increased, necessitating new methods for producing medical radioisotopes. Photonuclear reactions based on gamma sources have unique advantages in terms of producing high specific activity and innovative medical radioisotopes. However, the lack of experimental data on reaction cross sections for photonuclear reactions of medical radioisotopes of interest has severely limited the development and production of photonuclear transmutation medical radioisotopes. In this study, the entire process of the generation, decay, and measurement of medical radioisotopes was simulated using online gamma activation and offline gamma measurements combined with a shielding gammaray spectrometer. Based on a quasi-monochromatic gamma beam from the Shanghai Laser Electron Gamma Source (SLEGS), the feasibility of the measurement of production cross section for surveyed medical isotopes was simulated, and specific solutions for measuring medical radioisotopes with low production cross sections were provided. The feasibility of this method for high precision measurements of the reaction cross section of medical radioisotopes was demonstrated.
分类： 物理学 >> 核物理学 提交时间： 2023-06-20
摘要： The proton-proton momentum correlation function (Cpp) from di#11;erent rapidity regions are systematically investigated for the Au + Au collisions at di#11;erent impact parameters and di#11;erentenergies from 400A MeV to 1500A MeV in the framework of the isospin-dependent quantum molecular dynamics model (IQMD) complemented by the Lednick #19; y and Lyuboshitz analytical method.In particular, in-medium nucleon-nucleon cross section (NNCS) dependence of the correlation function is brought into focus, while the impact parameter and energy dependence of the momentumcorrelation function are also explored. The sizes of the emission source are extracted by #12;tting themomentum correlation functions using the Gaussian source method. We #12;nd that the in-mediumnucleon-nucleon cross section obviously in uence the proton-proton momentum correlation functionwhich is from the whole rapidity or projectile/target rapidity region at smaller impact parameters,but there is no e#11;ect on the mid-rapidity proton-proton momentum correlation function, whichindicates that the emission mechanism di#11;ers between projectile/target rapidity and mid-rapidityprotons.
分类： 物理学 >> 核物理学 提交时间： 2023-06-20
摘要： Two-nucleon momentum correlation functions are investigated for different single thermal sourcesat given initial temperature (T ) and density (). To this end, the evolutions of various singleexcited nuclei at T = 1 20 MeV and = 0.2 - 1.2 0 are simulated using the thermal isospindependent quantum molecular dynamics (T hIQMD) model. Momentum correlation functions ofidentical proton-pairs (Cpp(q)) or neutron-pairs (Cnn(q)) at small relative momenta are calculatedby Lednick y and Lyuboshitz analytical method. The results illustrate that Cpp(q) and Cnn(q) keepsensitivities to the source size (A) at lower T or higher , but almost not at higher T or lower . Andthe sensitivities become stronger for smaller source. Moreover, the T , and A dependencies of theGaussian source radii are also extracted by fitting the two-proton momentum correlation functions,and the results are consistent with the above conclusions.
分类： 物理学 >> 核物理学 提交时间： 2023-06-20
摘要： Momentum correlation functions of light (anti)nuclei formed by the coalescence mechanism of (anti)nucleons are calculated in several relativistic heavy-ion collision systems, namely B +B, O +O, Ca +Ca as well as Au +Au, at di#11;erent centralities at center of mass energy 39 GeV within the framework of A Multi-Phase Transport (AMPT) model complemented by the Lednick#19; y and Lyuboshitz analytical method. Momentum correlation functions for identical or nonidentical light (anti)nuclei are constructed in the above collision systems at so high collision energy. The results suggest that emission of light (anti)nuclei occurs from a source of smaller spacetime extent in more peripheral collisions. The e#11;ect of system-size on the momentum correlation functions of identical or nonidentical light (anti)nuclei is also explored in several central collisions. The results indicate that the emission source-size of light (anti)nuclei pairs deduced from their momentum correlation functions and system-size is self-consistent. Momentum correlation functions of nonidentical light nuclei pairs gated on velocity are applied to infer the average emission sequence of them. The results indicate that protons are emitted in average on a similar time scale with neutrons but earlier than deuterons or tritons in the small relative momentum region. In addition, larger interval of the average emission order among them is observed by large centrality and smaller system collisions.
点击量
通过
点击量
下载量
评论
