Subjects: Physics >> Nuclear Physics submitted time 2023-11-03
HE Yuan
WANG Meng
SUN Zhiyu
HU Zhengguo
XU Hushan
YAN Hexuan
XU Haowei
YIN Guoqing
WANG Pei
ZHANG Jiahui
Li Jinhai
HOU Dongsheng
ZHU Haofan
FAN Rui
XU Xinxing
ZHOU Xiaohong
LIU Zhong
LI Pengjie
WANG Kailong
LIU Jiajian
Abstract： Multinucleon transfer reactions involving heavy actinide projectile and target nuclei hold significant potential as a groundbreaking method to synthesize
neutron-rich superheavy nuclei. The construction of a Principled Spectrometer for Neutron-rich Superheavy Nucleus Research is highly desirable to establish the technical, methodological, and device foundation to explore the stability island in superheavy nuclei and to study the mechanism of multinucleon transfer reactions. The gas cell of the Principled Spectrometer requires a continuous supply of high-purity helium gas to stop the energetic radioactive reaction products and to extract the energy-reduced ions to the subsequent experimental setup. The paper focuses on a newly developed cryogenic purification system for the gas cell of the spectrometer. This cryogenic purification system is designed to provide recyclable and high-purity helium for the Principled Spectrometer. With a series of tests, the cryogenic purification system has been proven to be able to purify the 99% helium gas to 99.999% or higher, fulfilling the requirements of the gas cell when used in conjunction with the chemical purification system.
Subjects: Physics >> Nuclear Physics submitted time 2023-10-07
Abstract： The measurement of the muonic hydrogen atom Lamb shift is one of the most fundamental ways to obtain the proton charge radius experimentally. The theoretical calculation of the muonic hydrogen atom Lamb shift is necessary to extract the proton charge radius from the Lamb shift. In this work, we calculate the muonic hydrogen atom Lamb shift within the relativistic framework. The relativistic effect is described with the Breit-Pauli hamiltonian. The vacuum polarization effect is realized with the effective Uehling potential. With a high precision calculational method, Gaussian expansion method, we calculate the 2S1/2 and 2P1/2 levels of the muonic hydrogen atom. We find that the muonic hydrogen atom Lamb shift with considering the relativistic effect is about 0.09 meV larger than the one without considering the relativistic effect and the former one is closer to the experimental value.
Subjects: Physics >> Nuclear Physics submitted time 2023-09-11
Abstract： In this work, we presented the test results for a prototype of plastic scintillation detectors for time-of-flight measurement, aiming to provide preliminary research for the future development of time-of-flight detectors for HIAF-HFRS facility. Each timing detectors was composed of a fast scintillating plastic and four fast photomultiplier tubes coupled to its four sides. The time performance of the detectors was tested using pico-second pulsed laser, For two plastic scintillation detectors with different sizes, a pico-second pulsed laser was used to simulating the actual ion-beam situation by changing laser’s parameters including spot size, repetition rate, light intensity and hitting position. The data was processed utilizing CAEN-DT5742 digitizer and Mesytec-MCFD16+MTDC32 electronics. When the focused laser hit at the center of the plastic scintillators, the time-of-flight (ToF) resolution of two small-sized (7 cm×7 cm) plastic scintillation detectors could reach 8 ps, whereas the ToF resolution of the small and large (26 cm×10 cm) detectors could achieve 12 ps. After varying the parameters of the laser, the corresponding ToF resolutions were found to be in the range of 10–16 ps and 19–46 ps, respectively. The ToF resolutions from the test meets the timing-resolution requirement of the HFRS beamline, thereby establishing a solid foundation for further optimizing the time-of-flight detectors.
Subjects: Biology >> Radiobiology submitted time 2023-08-08
Abstract： Purpose: To investigate the mechanism by which mitochondrial ribosomal protein MRPS28 affects carbon ion irradiation-induced apoptosis in A549 cells.
Methods: siRNA was used to knock down MRPS28 and establish a stable MRPS28-knockdown A549 cell line; Cells were irradiated with carbon ion and X-ray; CCK-8 assay was performed to assess cell proliferation; Clonogenic survival assay measured cell survival rate; Flow cytometry detected apoptosis, reactive oxygen species (ROS), and mitochondrial membrane potential; qRT-PCR examined relevant genes; Western Blot analyzed apoptosis-related proteins.
Results: Exposure of non-small cell lung cancer A549 cells to carbon ion irradiation led to decreased MRPS28 expression; Compared to the control group, MRPS28 knockdown reduced A549 cell proliferation and clonogenic survival, increased ROS levels, decreased mitochondrial membrane potential, and induced apoptosis through the p53-mediated mitochondrial apoptotic pathway; MRPS28 knockdown combined with carbon ion irradiation significantly reduced A549 cell proliferation and survival, promoting apoptosis after irradiation.
Limitation: MRPS28 down-regulation increased the sensitivity of A549 cells to carbon ion irradiation, but the specific mechanism requires further investigation.
Conclusion: This study preliminarily demonstrates that MRPS28 down-regulation is involved in carbon ion irradiation-induced apoptosis in A549 cells and enhances A549 cell sensitivity to carbon ion.
Subjects: Nuclear Science and Technology >> Particle Accelerator submitted time 2023-07-25
Abstract： Based on KONUS dynamics, the beam dynamic design of a compact IH-DTL with built-in permanent magnet quadrupole lens was completed. The DTL is comprised by 37 acceleration gaps and two sets of permanent magnet quadrupole lenses, which can accelerate C6+ ion beam of 20 emA from 0.5 MeV/u to 4 MeV/u. To control the transverse and longitudinal emittance growth of the low-energy heavy ion beams, the gap voltage, injection phase, magnet parameters, and energy and phase settings of the 0-degree reference particles have been optimized so that the transverse normalized RMS acceptance of the IH-DTL reaches 0.37π mm·mrad, and the transmission efficiency is above 95%.
Subjects: Physics >> Nuclear Physics submitted time 2023-07-12
Abstract： The possible cluster structure of the proton drip-line nucleus $^{9}$C is of great significance for understanding the exotic structure of nuclei and nucleon interactions. Additionally, $^{9}$C plays a crucial role in nuclear astrophysics research. Thus great attention has been attracted by $^{9}$C. Researchers have conducted extensive experimental explorations on $^{9}$C, including studies of decay properties, energy level structure, magnetic dipole moments, nuclear astrophysics $S$ factor, and reaction cross sections. Numerous achievements have been made, but the knowledge on $^{9}$C is still insufficient. With the construction and operation of new generations of high-intensity heavy-ion accelerator facilities, combined with new experimental methods and higher efficiency detection equipment, it is expected to obtain more precise data and deepen our understanding of the exotic structure and reaction mechanisms of $^{9}$C.
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