分类： 物理学 >> 核物理学 提交时间： 2024-11-28
Xu, Dr. Zhao
Liu, Dr. Qi
Li, Prof. Wen-Yi
Feng, Ms. Guangyan
Lu, Mr. Yu
Ding, Ms. Ziyi
Li, Dr. Tao-Sheng
摘要： This study investigates the hyper-radiosensitivity (HRS) and induced radioresistance (IRR) effects in cells exposed to low-dose radiation, focusing on identifying critical dose thresholds and exploring underlying molecular mechanisms. By analyzing cell survival data using a normal distribution-based mathematical model, we determined two key dose thresholds: D0 , where repair mechanisms are activated, and D1 , where repair and damage rates equilibrate. Our findings reveal that ATM (ataxia-telangiectasia mutated) and p53 proteins play central roles in modulating these thresholds, with wild-type p53 cells demonstrating faster repair initiation and mutant p53 cells exhibiting broader response curves. The results show that cellular outcomes depend on both genetic background and radiation dose, with potential implications for optimizing radiotherapy protocols and developing radioprotective strategies. This work provides a quantitative framework for understanding HRS and IRR phenomena and contributes to advancing personalized approaches in radiation medicine.
分类： 物理学 >> 核物理学 提交时间： 2024-12-16
wang, Dr. haitao
Zhang, Prof. Yan
Liu, Mr. Chi
Xu, Mr. Jian-Qiang
Zhang, Dr. Li-Jiao
LIU, Prof. Zhi-feng
Zhang, Dr. Xiongjie
Chen, Dr. Rui
Liu, Dr. Qi
Wang, Dr. Ren-Bo
Zhou, Mr. Shumin
Tang, Prof. Bin
摘要： The domestically developed prompt fission neutron uranium logging(PFNUL) instrument for uranium exploration represents a significant advancement in China deep uranium mining efforts, though it comes with considerable challenges and complexity. This paper presents the development of a new prompt fission neutron uranium logging instrument(named UNL4) , integrates a domestic D-T neutron generator, two 3He proportional detectors, a lanthanum bromide (LaBr3) gamma-ray detector, and digital multi-channel pulse amplitude analyzer. The near 3He detector is shielded with 1mm of Cadmium (Cd) and 5mm of high-density polyethylene(HDPE), enabling efficient epithermal neutron detection, while the far 3He detector measures thermal neutron. The LaBr3 detector is employed for gamma-ray detection, primarily originating from uranium decay. High-speed ADC and FPGA technologies were used to achieve rapid acquisition and transmission of both dual neutron time spectra and gamma spectra.Moreover, this paper proposes a fast signal shaping method, which reduces the dead time effect in ^3He detectors on neutron time spectra. Experiments conducted in standard model boreholes with varying uranium content demonstrated a strong linear relationship between the epithermal-to-thermal neutron ratio (E/T) and uranium content, with a fitting coefficient of R2>0.999, confirming the instruments accuracy. The E/T value repeatability, both in short-term (3.16% RSD) and long-term (1.2% RSD) measurements, showed excellent stability. In addition, the instrument demonstrated good performance at neutron logging speeds of 0.3∽3 m/min (E/T values) and gamma logging speeds of 1∽10 m/min. By conducting measurements in two ore sections of the PU model with lithium contents of 87.1 ppm and 45.6 ppm, the RD is less than about 10% in both logging cases, meeting the requirements for engineering applications. This marks the first successful development of a neutron logging instrument for uranium exploration based on a domestic neutron generator, signifying an important contribution to uranium resource exploration.
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