In the event of a nuclear emergency，it is crucial to quickly assess the radiation levels within the nuclear power plant site. To address the issue of the rapid changes in the radiation field after a nuclear accident and the potential failure of the fixed monitoring network，this study has developed a low-power gamma radiation detection module based on LoRa. The system employs a dual-probe detector with scintillation and semiconductor sensors. Through both hardware and software low-power designs，it achieves wide-range，low-power long-term continuous monitoring. Utilizing the self-organizing network technology of the LoRa module，it supports rapid multi-point deployment and long-distance wireless transmission. Test results indicate that the module operates stably in complex environments，with low power consumption and reliable data. It meets the needs for rapid response in nuclear emergencies and wide-area radiation monitoring，and has good prospects for engineering applications.
Personal dose monitoring and environmental radiation monitoring are commonly conducted in places such as nuclear power plant reactor operations and nuclear medical facilities，often using thermoluminescent dosimeters (TLD). However，conventional devices like TLDs suffer from limitations in terms of real-time capability and readout convenience. To address the requirements of environmental and personal dose monitoring，this study carries out simulation research and experimental testing on a novel type of direct ion storage (DIS) dosimeter. A comprehensive simulation model is established through Monte Carlo simulations and technology computer-aided design (TCAD) for semiconductor process and device simulation. Combined with existing dosimeters，dosimetric characteristic tests are performed in radiation fields. As a result，a general simulation model for the DIS detector is developed，the overall structural parameters are designed，and a quantitative relationship between radiation dose and drain current is established. Based on the simulation results，compensation optimization of the existing dosimeter is performed using 1.6 mm PMMA or 1 mm aluminum，improving the energy response within the test range from ±30% to within ±20%. This study provides theoretical and technical support for further development of DIS dosimeters and serves as a reference for the research and application of novel DIS detectors.
During the detection of releasers from nuclear fuel plants，the isotope 85Kr presents a challenge due to its exceptionally low γ branching ratio of approximately 0.434% and the complex bremsstrahlung mechanism that follows β radiation，where the branching ratio exceeds 99.5%. This complexity complicates the precise inversion of 85Kr activity within a sealed container. To investigate the interference effects under realistic working conditions，a cylindrical three-dimensional model was developed. Dynamic analyses were performed to assess the effects of varying container wall thickness (0.5-1.5 mm)，container material (aluminum，brass，stainless steel)，85Kr source gas pressure (1.0-5.0 atm)，and container inner diameter (1.9-5.9 cm). The dose rate response function and bremsstrahlung radiation leakage ratio were compared across these variables. The results indicate that: (1) The wall thickness of the container is significantly negatively correlated with the proportion of bremsstrahlung leakage，leading to nonlinear distortion of the dose rate response function in the near-field area. This finding suggests that wall thickness tolerance is a primary source of systematic error; (2) Low-Z materials，such as aluminum，due to small photoelectric cross-sections and low mass thicknesses,exhibit poor self-absorption of low-energy photons，resulting in a markedly higher proportion of bremsstrahlung leakage compared to high-Z materials，such as brass; (3) The gas pressure of the radioactive source demonstrates a significant positive correlation with the proportion of bremsstrahlung radiation leakage. However，under the same detection distance，the dose-rate response function remains largely unchanged; (4) The inner diameter of the container reveals a significant nonlinear relationship with the proportion of bremsstrahlung leakage. Nevertheless，containers with a larger inner diameter substantially reduce the effective detection efficiency per unit activity. This research establishes a correction model for geometric parameters and pressure variations within the container during the 85Kr activity inversion process，thereby providing a theoretical foundation for enhancing the accuracy of the 85Kr online monitoring system and the precision of the inversion system，which holds considerable reference value for engineering applications.
To achieve the absolute measurement of 239Pu activity,a method combining inductively coupled plasma mass spectrometry(ICP-MS)with liquid scintillation counting(LSC)was proposed.The total α activity of the sample was measured using the triple-to-double coincidence ratio(TDCR)mode of a liquid scintillation counter,and the atomic ratio of 239Pu to 240Pu was determined by ICP-MS.The activity of 239Pu was then calculated using the decay constants.The nitric acid concentration for sample dilution was optimized to be 0.6-0.8 mol·L-1 to suppress quenching and adsorption.The pulse level index(PLI)was set to 14.A plutonium solution was measured,and the repeatability of the total α specific activity measurement was 0.49%,remaining stable over a seven-day observation period.The specific activity of 239Pu was 184.47 Bq/g,accounting for 93.11%of the total α activity.The relative expanded uncertainty of the measurement was 1.4%(k=2),with major contributions from the sample weighing,coincidence resolving time,and isotopic ratio measurement.This method does not require standard solutions for efficiency calibration and is essentially an absolute measurement.The applicability of this method to simple plutonium solutions has been validated,providing metrological technical support for nuclear material accounting and nuclear safeguards.
To address the requirement for accurate activity measurement of the medical α-emitting radionuclide 223Ra in radiopharmaceutical development and clinical application，this study established a triple-to-double coincidence ratio (TDCR) Cherenkov counting method for measuring 223Ra activity. In this work，a TDCR liquid scintillation counter was used to calibrate the activity of 223Ra. The Cherenkov spectra of 223Ra and the TDCR efficiency correction curve was obtained. The Cherenkov spectra，detection efficiencies，and the effects of color quenching between 223Ra and 224Ra were compared. The results showed that Cherenkov light originating from the daughter nuclides 211Pb and 207Tl can be used for accurate activity determination of 223Ra，with a maximum detection efficiency of up to 60% and a minimum detectable activity of 0.2 Bq. A good correlation was observed between TDCR values and the detection efficiency of 223Ra，enabling efficiency correction in activity measurements. The TDCR Cherenkov counting method exhibited similar detection efficiencies for 223Ra and 224Ra，whereas color quenching affected 223Ra more significantly. This study demonstrated that TDCR Cherenkov counting offers a sensitive，accurate，and rapid approach for determining the activity of 223Ra，supporting radiopharmaceutical development and clinical applications.
To address the problems of low efficiency，poor consistency，and high radiation exposure risk associated with manual，sequential calibration measurements in the quality control of carbon-14 radioactive sources used in ambient particulate matter monitors，an automated activity measurement system was developed. The device integrates an automatic sample loading tray，a high-precision activity measurement unit，a sorting actuator based on stepper motors and suction tips，and intelligent control software. By using a dedicated algorithm，it enables rapid activity calculation and automatic pass/fail judgment，and physically sorts out nonconforming products. The system can process up to 100 radioactive sources in a single batch，achieving a gauge repeatability and reproducibility (R&R) value of 13.1%，a number of distinct categories (NDC) of 16，and a sorting accuracy exceeding 99.0%. Compared with manual operation，the efficiency is improved by 49.2%，while human intervention and radiation exposure risks are significantly reduced. The system realizes fully automated，high-throughput activity measurement of carbon-14 sources，greatly enhancing inspection efficiency and consistency，and providing reliable technical support for ensuring the accuracy of environmental monitoring data at the source.
Due to the tight supply of industrial cobalt sources and concerns about the safety risks of high-activity radioactive sources，the application of gamma irradiation technology is restricted，making it difficult to meet the growing demand for irradiation processing. Although the application of electron accelerators for irradiation processing has developed rapidly in recent years，it is limited by its energy and has a weak penetration ability，thus cannot be widely used. X-ray have obvious advantages over gamma rays and electron beams can serve as an important supplement. China’s irradiation processing industry is booming，and the application of gamma and electron beam devices is mature. Although X-ray irradiation technology has been applied in China，there are still significant gaps in key technologies and promotion of domestic X-ray irradiation devices.This article expounds the basic principles and key technologies of X-ray irradiation，and compares it with gamma and electron beam irradiation technologies，comprehensively analyzing the characteristics and advantages of X-ray irradiation technology. By summarizing research achievements in X-ray irradiation technology，it is evident that as the technology advances，equipment costs and operating expenses have decreased，making it a new focal point and starting point for international irradiation processing technology development. Our country should strengthen the research on key technologies of X-ray irradiation devices，and strive to achieve the complete domestic production of X-ray irradiation devices as soon as possible. China should strengthen research on key technologies for high-energy X-ray irradiation facilities，achieve full domestic production of these systems as soon as possible，keep pace with technological development trends，and thereby elevate the overall level of China’s irradiation processing technology.
The synthesis of superheavy elements has long been one of the forefront topics in the field of nuclear physics. Utilizing actinide rare nuclides as target materials and inducing nuclear reactions with heavy-ion beams represent a key approach for synthesizing superheavy elements. However，the stable supply of actinide rare nuclide targets has become a critical bottleneck restricting further advancements in superheavy element synthesis. The Tsinghua High Flux Reactor (THFR)，characterized by its high neutron flux and strong irradiation capability，can provide essential support for the production of actinide rare nuclide targets，thereby facilitating the experimental discovery of superheavy elements. This paper first reviews recent progress in superheavy element synthesis and then explores potential pathways for applying THFR to cutting-edge nuclear physics research，with a focus on analyzing the feasibility of using THFR to supply target materials for superheavy nuclei synthesis. Through theoretical calculations，key parameters such as yield and purity of the primary actinide rare nuclide targets that can be produced by THFR are presented. The findings offer valuable references for preparation of targets on superheavy nuclei synthesis based on ultra-high flux reactor.
The increasing demand for high-flux neutron detection，driven by next-generation neutron sources，necessitates alternatives to conventional 3He proportional counters，which are limited by space charge effects. This paper presents the development and experimental validation of a thermal neutron detector based on Gas Electron Multiplier (GEM) technology. Key detector parameters were systematically optimized using Monte Carlo simulations (Geant4，Garfield++，SRIM). An Ar/CO2 mixture with Ar>90% was selected as the working gas，an approximately 1 μm thick 6LiF coating was employed as the neutron conversion coating，and the electric field settings were optimized to EDrift≈150 V/cm，VGEM≈400 V，and EInduction>1.0 kV/cm. A prototype detector featuring a two-dimensional readout structure with an active area of 44 mm×44 mm was fabricated based on these optimized parameters. Preliminary performance tests conducted in a thermal neutron field demonstrated that the detector achieves measurement uniformity comparable to that of a 3He proportional counter，while providing millimeter-level geometric resolution in a single measurement. The counting rates in the “X” and “Y” directions are in good agreement with the theoretical values，laying a solid foundation for subsequent measurement applications under high-flux neutron beams.
Extreme rainfall events occur frequently under the background of global climate changes. As an important contributor to extreme rainfall，typhoons exert significant impacts on regional environment and social economy. Xishuangbanna，located in the southernmost tropical region of Yunnan province，serves as the terminal affected area of westward-moving typhoons. Investigating precipitation δ2H and δ18O in this region can provide a scientific basis for deciphering the water vapor transport pathway and controlling mechanism of typhoons in tropical China. In this study，rainfall samples were collected before，during，and after multiple typhoon events in Xishuangbanna from 2021 to 2024. Combined with the HYSPLIT backward trajectory model and meteorological data，the temporal variations and dominant controlling factors of δ2H and δ18O in precipitation were analyzed. The results show that the δ2H and δ18O in typhoon-related rainfall exhibited a distinct three-stage variation pattern with a unique delayed depletion feature，which usually occured 1-3 days after the typhoon. The depletion magnitude of δ2H and δ18O in rainfall was mainly controlled by typhoon intensity and the distance between the typhoon low-pressure center and the study region. The correlations between precipitation isotopes and local meteorological factors were more weak with the increasing typhoon intensity，and the influences of local meteorological factors were completely masked during the super typhoons. This study filled the research gap of δ2H and δ18O in typhoon-related rainfall in Xishuangbanna，and provided implications for understanding the disturbance of typhoons on inland water cycle processes and optimizing regional water resource management.
Reactor irradiation of enriched 146Nd targets represents an important route for the production of 147Pm，where the major challenge lies in the efficient separation of trace 147Pm from a bulk Nd matrix. To establish a feasible separation process of 147Pm/Nd，the adsorption and separation behaviors of Nd and 147Pm on AG 50W×8 strong-acid cation-exchange resin were systematically investigated. Samarium was employed as a chemical surrogate for 147Pm during the optimization of process parameters.Batch adsorption results demonstrated that，in dilute hydrochloric acid media (0.0001-0.1 mol/L HCl)，Nd and 147Pm reached adsorption equilibrium within 10 min. The adsorption kinetics followed a pseudo-second-order model，and the adsorption isotherms were well described by the Langmuir model. The maximum adsorption capacities of the resin for Nd(Ⅲ) and Sm(Ⅲ) were determined to be 236.9 mg/g和210.9 mg/g，respectively，from which the adsorption capacity of 147Pm can be reasonably inferred to lie between those of Nd and Sm. Based on the batch adsorption results，systematic column separation studies were carried out using Sm as a surrogate for 147Pm. The optimal chromatographic conditions were determined to be 0.4 mol/L α-hydroxyisobutyric acid (α-HIBA) as the eluent at pH 4.1，a flow rate of 1.0 BV/h，and a temperature of 75 ℃. Under these conditions，separation experiments using 147Pm as a tracer demonstrated that 147Pm was preferentially eluted prior to Nd，achieving a resolution of 1.21 and a recovery yield exceeding 88.1%.This study establishes a cation-exchange chromatographic process coupled with complexing elution for the separation of 147Pm from Nd，providing a practical experimental basis for the purification of 147Pm from irradiated 146Nd targets.
To address the heavy reliance on imported medical cyclotrons in China，the China Institute of Atomic Energy has independently developed a 10 MeV ultra-compact cyclotron，aiming at achieving localized and low-cost production of medical radioisotopes. The device incorporates key technologies including shallow-valley magnets，an integrated high-frequency and vacuum system，single-pass axial shimming，and an internal Penning ion source. It has a compact footprint of less than 1.4 m3 and a total weight under 7.5 tons，and is designed for high integration and intelligent operation and maintenance. Under working conditions of 10 MeV proton energy with 80 μA beam current，the cyclotron maintained stable operation for 2 h，yielding 18F with an activity of over 3 Ci. This output is sufficient for approximately 15 patient doses，fulfilling the clinical demand. The results demonstrate that this accelerator is reliable，user-friendly，and suitable for in-hospital production of short-lived medical radioisotopes such as 18F and 68Ga.
The past decade(2016-2025)marks a strategic transition period for China's isotope technology to transform from reliance on imports to independent innovation.To systematically analyze the breakthroughs and existing challenges in this field,this paper examines seven key areas over the past decade:national policy planning,production facility construction,research and development of core technologies,market entry of isotope products,radioactive source applications,radiopharmaceuticals,industrial park layout,and R&D platform construction.It integrates policy documents,technical reports,and industrial data,conducts a comprehensive review and summary,and analyzes existing issues and shortcomings.Suggestions for subsequent development have been proposed in response to the identified issue.
To expand the coverage of data points used for fitting the relative efficiency curve in plutonium Isotopic Composition analysis via gamma spectrometry，and to enhance the accuracy of the relative efficiency curve fitting，the block coordinate descent method is employed to normalize the relative detection efficiencies at different energy points of distinct nuclides. Outlier data points are removed based on the 3σ criterion，and the remaining points are used to fit the relative detection efficiency curve. The energy spectra of plutonium samples with three different abundances were analyzed using the approximation method，the interpolation method，the block coordinate descent method，and the two energy regions defined in FRAM. The results show that the maximum deviation of the 239Pu content obtained by the block coordinate descent method from the nominal value is 3.4%, which is a significant improvement compared to the approximation method and the interpolation method. The root mean square error of the relative detection efficiency curves fitted by the block coordinate descent method under three shielding conditions is calculated. The result with 2 mm cadmium shielding is the best and 2 mm cadmium is suitable for the analysis of sample abundance.
Gastrin-releasing peptide receptor (GRPR) is highly expressed in prostate cancer，breast cancer，and gastrointestinal tumors，but lowly expressed in normal tissues and organs，providing an ideal target for molecular imaging. Existing research has fully validated its biological basis and clinical value，but the core of truly driving clinical translation lies in the continuous optimization of its molecular structure. This article reviews the development and evolution of GRPR-targeting molecular probes: the shift from early agonists to antagonists has significantly improved metabolic stability and imaging contrast; simultaneously，strategies such as peptide modification，dimer design，linker arm regulation，chelator matching，and radionuclide selection have further enhanced tumor uptake and image quality. In the future，multi-target molecular design，therapeutic integration，and patient-stratified personalized applications will become important directions for enhancing the clinical value of GRPR-targeted imaging.
As an ultra-trace heavy nuclides，Pu have important applications in fields such as nuclear environmental protection，nuclear astrophysics，and geological research. Accelerator mass spectrometry (AMS)，with its low detection limits，high measurement sensitivity，and effective capability to overcome interferences from isobars and molecular ions，is the most suitable method for measuring Pu isotopes such as 239Pu and 242Pu. This work，based on the 300 kV AMS system at the China Institute of Atomic Energy (CIAE)，conducted research on Pu measurement methods. The study primarily included investigations into negative ion extraction from the ion source，high-efficiency system transmission，background exclusion，and particle identification techniques. Ultimately，a high-efficiency transmission and high-sensitivity measurement method for Pu was established. Measurement results of standard samples were consistent with their nominal values and demonstrated excellent stability，with a detection limit of 2×106 atoms (0.8 fg) for 239Pu.
68Ge serves as the pivotal parent nuclide for the medical positron emitter 68Ga,rendering target design and fabrication critical for cyclotron-based production.This study systematically investigates the preparation of sealed Niobium-gallium capsule targets.Firstly,yield simulations using the FLUKA were conducted to the target design.Gradient experiments on gallium cavity depth and filling ratio were performed to determine the optimal target parameters and electron beam welding safe distance.The effect of gallium filling on welding performance was investigated through weld penetration analysis and X-ray diffraction.Subsequently,quality control was implemented through computed tomography imaging,helium mass spectrometry leak testing,and thermal shock experiments to ascertain high-temperature failure reason.Finally,hot experiments verified reliability of targets.The results indicate that excessive gallium will increase weld penetration and form the Ga5Nb4 compound,resulting in fracture failure of the target component.The optimal target structure is achieved at a gallium cavity depth of 1.35 mm and a filling ratio of 68%-72%.The target exhibits excellent hermeticity(leak rate<5×10-3 Pa·cm3/s)and thermal stability below 400℃.Hot experiments yielded approximately 2.7-3.9 GBq of 68Ge with radiochemical purity higher than 99.9%and element impurities below 2 ppm.This study demonstrates superior performance of niobium-gallium capsule targets fabricated via electron beam welding,providing critical process support for the scalable and safe production of 68Ge.
Stable isotope technique has been used to attribute carbon dioxide (CO2) emissions to different processes，and over the past two decades their use has come to the forefront as a promising tool for CO2 source partitioning. Accurate quantification of carbon dioxide (CO2) (and other greenhouse gases) as a result of the activities of soil microorganisms is important for understanding soil respiration process and predicting carbon exchange between soil and atmosphere. Recently，laser-based analyzers have become commercially available for simultaneously measurements of the concentrations and the isotopic composition of CO2，using cavity-enhanced absorption spectroscopy for the analysis of ambient air samples. However，despite this innovation for the possibility of in situ field measurements，their use raises unique demanding for an on-line gas sampling and displacement auxiliary. In order to realize the continuous measurement of soil microbial respiration，this study aimed to establish an online analytical method suitable for continuous in situ monitoring of CO2 concentration and its δ13C value from soil microbial respiration gases. Based on CRDS technology，a self-developed multi-channel online gas exchange and sample introduction device was integrated with a carbon stable isotope analyzer (G2201-i) to construct an automated continuous monitoring system. Tests using a series of standard gases demonstrated that the system achieved high accuracy and precision in measuring CO2 concentration and δ13C values. The measured values were consistent with reference values，with a coefficient of variation for concentration measurements less than 0.1% and δ13C measurements below 0.5‰，meeting practical testing requirements. The application of this system to in situ soil microbial respiration studies yielded results consistent with those obtained by traditional gas chromatography-isotope ratio mass spectrometry (GC-IRMS) (correlation coefficients R2 were 0.999 and 0.997，and slopes were 0.998 and 0.995，respectively)，validating the reliability of the method. The established method enables synchronous，high-precision，and automated in situ measurement of CO2 and its isotopic composition from soil microbial respiration. It exhibits excellent timeliness and stability，providing a key technical solution for in-depth investigation into soil organic carbon transformation processes and microbial driving mechanisms. This method holds significant application value for the precise quantification of carbon fluxes in terrestrial ecosystems.
Klystron is a core vacuum electronic device for high-power microwave systems and is widely applied in fields such as particle accelerators，controlled nuclear fusion，and radar communication. Its key performance indicators including output power，gain and efficiency are mainly determined by the interaction efficiency between the electron beam and the high-frequency field. To meet the application demand of high-performance klystrons for high-quality electron beams with low fluctuation rate，a study on the design and optimization of the magnetic field and electron optical structure in the transition region of an applied C-band high-power klystron was carried out. The structural design of the electron gun was completed by the synthesis method，a magnetic field calculation model for the transition region was established，and the requirements for the electromagnetic field distribution in the transition region were proposed. Combined with the electron beam envelope of the electron gun，the fluctuation rate of the whole klystron was calculated. A multi-physics field simulation model is constructed using software such as POISSON and CST，and a reverse coil structure is adopted to achieve precise magnetic field matching. The reliability of the calculation results is verified through cross-validation of 2D and 3D simulation results.The final calculated beam ripple is 4.32%. This design method provides important theoretical support and practical reference for the high-performance design of the magnetic field in the transition region of high-power klystrons.
γ-ray spectral analysis serves as a core technology in nuclear radiation detection，environmental radioactivity monitoring，and nuclear security applications. However，in practical measurements，factors such as overlapping characteristic peaks，statistical fluctuations，and detector nonlinear response increase the difficulty and uncertainty of.manual spectral interpretation. To address these issues，this study proposes a γ-spectrum analysis method based on Fuzzy Neural Networks for nuclide identification and prediction of activity or enrichment，skipping traditional spectrum interpretation steps. First，fuzzy C-means clustering (FCM) is applied to partition spectral data，extracting membership degree features. These features are then fused with measurement condition characteristics and fed into a neural network to extract vector features，ultimately outputting radionuclide types along with predicted activity or enrichment. Experimental results demonstrate that the model achieves 100% accuracy in identifying 137Cs，60Co and 133Ba， and shows a mean value of absolute relative deviation of 2.02% of activity prediction. The RMSE for predicting the activity of 137Cs，60Co，and 133Ba respectively are 213.18 Bq，944.31 Bq，and 10926.79 Bq. The relative deviations between their RMSE and the actual activity average values respectively are 2.89%, 2.11%，and 1.70%. The uranium enrichment prediction shows a mean value of absolute relative deviation of 11.84% and RMSE of 11.73%，indicating room for improvement. This approach effectively integrates fuzzy feature representation and measurement condition information，providing a viable solution for intelligent γ-spectrum analysis.
