Subjects: Nuclear Science and Technology >> Radiation Physics and Technology Subjects: Physics >> Nuclear Physics submitted time 2026-04-28
Abstract： During the measurement of low- and intermediate-level radioactive waste (LILW), various factors can obscure weak peaks in low-count gamma spectra to different extents. Hence, before the gamma spectra of LILW are analyzed, these factors should be eliminated through effective smoothing. This study aimed to address the loss of weak peak information in gamma spectra due to the low energy resolution of LaBr3(Ce) detectors during smoothing. For the first time, this study integrated the discrete wavelet transform (a transform that decomposes a given signal into a number of sets), Nyquist sampling rate (the lowest sampling rate that permits accurate reconstruction of a sampled analog signal), and fast Fourier transform (an algorithm that computes the discrete Fourier transform of a sequence). Through this integration, this study established an optimal criterion for the decomposition level, an adaptive threshold correction model, and a novel threshold function tailored to smoothing low-count gamma spectra. Experimental results demonstrated that the proposed method enhances the signal-to-noise ratio of an original gamma spectrum by 2.51 times. Compared with traditional methods, the novel method substantially reduced the root mean square error between the smoothed and original spectra by 87.1%, achieving this with a lower smoothness value. Furthermore, it mitigated channel distortions in the full-width at tenth-maximum for the characteristic peaks of the low-count spectrum by 75.0% to 96.9%. Under different peak distances, the peak-to-valley ratio of the overlapping peaks smoothed by the novel method increased by up to 7.4% compared with other methods. This method removes noise efficiently, preserves the original data of low-count spectra, and optimizes the peak-to-valley ratio of overlapping peaks. The results of this research
broaden the potential application scenarios of the LaBr3(Ce) detector in LILW measurements, as well as in other fields, such as regional geophysical exploration, radiation environment monitoring, nuclear medicine, and astrophysical measurements. It substantially reduces the cost of establishing measurement systems for low-activity radioactive materials in complex environments.
Peer Review Status:
Awaiting Review
Subjects: Nuclear Science and Technology >> Nuclear Science and Technology submitted time 2026-04-27
Jianhong Li
Junhong Xu
Yongde Fang
Zihao Jia
Wen Liang
Yuhong Tan
Xingshuo Feng
Youyu Li
SALEH SANUSI
Zhixuan Wang
Qianchao Zhang
Abstract： CsI(Tl) detectors are widely employed for charged-particle identification (PID) in nuclear physics experiments owing to their reliable pulse-shape discrimination (PSD) capability. To overcome the limitations of existing digital PID methods—large data volume, high computational complexity, and insufficient real-time performance—this paper proposes a QDC-Matrix-based algorithm. The algorithm is based on the tri-exponential decay model of the
CsI(Tl) signal, in which the three exponential terms correspond to the fast scintillation component, the slow scintillation component, and the electronic response component, respectively. By dividing the digitized waveform into multiple integration segments and exploiting the temporal correlation between each segment integral and the tri-exponential function, a system of linear equations is constructed. Solving this system yields the amplitudes of the fast and slow components. Charged-particle identification is then achieved rapidly using the fast-to-slow amplitude ratio, which exhibits a strong dependence on particle species. Unlike conventional approaches that require full waveform data, this method significantly reduces data transmission and storage overhead. Monte Carlo optimization of the integration intervals further ensures discrimination performance comparable to full-waveform fitting across the full energy range. Experimental validation on typical fusion-evaporation reaction data demonstrates that the QDC-Matrix algorithm outperforms the charge-comparison method and achieves results highly consistent with full-waveform fitting, substantially improving particle-𝛾 coincidence statistics. The proposed algorithm provides a new, efficient, and practical solution for high-performance PID in CsI(Tl) detector arrays used in nuclear physics experiments.
Subjects: Nuclear Science and Technology >> Particle Accelerator submitted time 2026-04-26
PengBo, Chen
ShaoYi, Wang
WenBo, Zhang
RongWei, Zha
Bin, Sun
JiaXing, Wen
Cheng, Lei
ZongQing, Zhao
Du, Wang
Abstract： Dielectric laser accelerators (DLAs) can achieve acceleration gradients exceeding those of conventional radio-frequency accelerators by one to two orders of magnitude. Existing DLA design approaches rely heavily on empirical parameter tuning and single-variable optimization, which fundamentally constrains performance enhancement. Here, a new optimization strategy for DLA structures is proposed based on the Gated Adaptive Network for Deep Automated Learning of Features (GANDALF). This framework integrates key parameters such as geometric configurations, material properties, and optical field characteristics into a comprehensive analysis. By accurately predicting particle energy gain, the structural parameters are optimized, significantly improving DLA performance. The proposed approach outperforms traditional computational methods, particularly for nonperiodic structures, enabling continuous particle acceleration. The GANDALF model demonstrates high accuracy, robustness, and adaptability, yielding an average acceleration gradient of 2.8 GV/m (Y2O3), enabling sustained acceleration in the majority of the acceleration channel, with a beam spot radius of 3.13 µm. Additionally, a cascaded DLA design concept is introduced and validated, paving the way for extended acceleration lengths on photonic chips.
Subjects: Physics >> Nuclear Physics submitted time 2026-04-25
Abstract： The high density fuels, including uranium monocarbide UC, UN, and the uranium carbonitride U(CN) that results from carbon impurities following UN fabrication, have recently attracted attention for light-water reactor (LWR) applications because of their facilitation on increased 235 U loading at a fixed enrichment, high thermal conductivity and high melting temperatures. Despite these favorable properties, numerous performance aspects must be evaluated before any lesser-studied uranium compounds become viable LWR fuel forms. This study is first to perform thermodynamic calculation to evaluate thermal stability pure UC and UN in a closed system mimicking Pressure-water reactor (PWR) coolant, based on which UN or UC is not thermodynamically stable in any aqueous electrochemical system during a cladding breach. Then the potential interactions between UN and UCN with Zr or SiC cladding were systematically evaluated using a thermodynamic database of U-Zr-Si-C-N was developed in this work using the CALPHAD approach and validated with available literature data. The interfacial stability of UN/Zr, UC/Zr, UN/SiC and UC/SiC were assessed by calculating the isothermal sections U-Zr-N, U-Zr-C, U-Si-C, U-Si-C-N at 1500,1000 and 500 C, as well as the isopleth sections of U(C 0.3 N 0.7 )-Zr. The results predict that a complex reaction pathway between UN and Zr will produce multiple layers including phases of bcc(U,Zr), UZr2, hcp(Zr,N) and fcc(U,Zr)N. This response is more complicated than that between UC and Zr where a single ZrC layer is predicted. Improved thermodynamic stability is predicted when compatability with SiC cladding is considered. Both UN and UC are in equilibrium with SiC when modeled under the same temperature conditions. Potential carbon impurities present in UN as a result of the fabrication process were not found to contribute detrimentally to fuel-cladding contact for either Zr or SiC cladding under conditions evaluated here.
Peer Review Status:Awaiting Review
Subjects: Physics >> Nuclear Physics submitted time 2026-04-24
Abstract： Shape quantum phase transition is an important and hot topic in nuclear structure. In this paper, we begin to study the finite-N shape quantum phase transition in the SU3-IBM. In this new proposed model, new spherical-like γ-soft spectra was found to resolve the spherical nucleus puzzle, which is a new γ-soft rotational mode. In this paper, the shape phase transition along the new γ-soft line is first discussed, and then the neighbouring case at the prolate side is also studied. Some key quantities are discussed. We find that double shape phase transitions occur along a single parameter path. The new γ-softness is really a shape phase and the shape phase transition from the new γ-soft phase to the prolate shape is found. The experimental supports are also found and108Pd may be the critical nucleus.
Subjects: Physics >> Nuclear Physics submitted time 2026-04-24
Zhu, Ms. Songxian
Jia, Dr. Huiming
Lin, Dr. Chengjian (Nuclear physics)
feng, Prof. jing
Qiu, Dr. Yijia
Liu, Prof. shilong
yang, Dr. yi
Yang, Dr. Lei
Ma, Dr. Nanru
Yang, Dr. Feng
Wen, Mr. Peiwei
Luo, Mr. Tianpeng
chang, Mr. Chang
Duan, Ms. Hairui
Zhang, Dr. Huanqiao
Abstract： To further study the heavy-ion nuclear reaction mechanisms and fission of actinide nuclides by using the surrogate reaction method, a compact and efficient hybrid detector array for coincidence measurements of the beam-like particles and fission fragments has been developed and tested online. This detector array consists of four silicon strip detector telescopes and two parallel-plate avalanche counters. For the near-barrier \(^{7}\mathrm{Li} + ^{238}\mathrm{U}\) reaction, the fission fragments correlated with the beam-like \(^{6}\mathrm{He}\) particles originating from the transfer reaction were confirmed by analyzing the folding angle. The fission barrier height for the short-lived actinide nucleus \(^{239}\mathrm{Np}\), produced in the \(1p\) stripping channel, was extracted from its fission probability. The deduced value shows a good agreement with the existing literature data.
Peer Review Status:Awaiting Review
Subjects: Physics >> Nuclear Physics submitted time 2026-04-23
Abstract： Background: The exploration of neutron-rich nuclei far from stability has revealed exotic phenomena like the change of magic numbers, shape coexistence, and halo formation. Neutron-rich magnesium isotopes provide a pivotal testing ground for understanding how shell evolution, deformation, and continuum coupling collectively govern nuclear structure near the drip line. Purpose: This work aims to systematically investigate the ground-state properties and the emergence of deformed neutron halos in even-even magnesium isotopes34−44Mg, with a focus on the microscopic mechanisms driving shell closure quenching, deformation development, and halo formation. Methods: We employ the deformed relativistic mean-field theory combined with the complex momentum representation and BCS pairing (DRMF-CMR-BCS). This framework self-consistently treats deformation, pairing correlations, and continuum coupling, providing a unified description of bound, resonant, and continuum states. Calculations are performed using the NL3 effective interaction. Results: Our calculations reveal the microscopic mechanism for the collapse of the N = 20 and N = 28 shell closures, identifying it as a cooperation of monopole drift in key neutron orbitals (e.g., 1/2−1, 3/2−2) and the stabilization of prolate deformation. In 40,42,44Mg, we predict the universal emergence of deformed halos characterized by a striking shape decoupling: a prolate core coexists with an oblate halo. This halo is predominantly formed by low-angular-momentum orbitals, with the dominant contributor shifting from a narrow resonant state (3/2−2) in 40Mg to a weakly bound orbital (3/2−2) in 42Mg. The anomalous occupancy of narrow resonances underscores the important role of pairing, enhanced continuum coupling. Conclusions: The structure of neutron-rich Mg isotopes is governed by the intricate competition between single-particle energies, deformation, pairing, and the continuum. Our calculations offer clear, testable predictions for future rare-isotope beam experiments.
Peer Review Status:Awaiting Review
Subjects: Physics >> Nuclear Physics submitted time 2026-04-23
Long, Mr. Yi
Wang, Mr. Yue-Hua
Zhan, Mr. Dong
Li, Prof. Shuang
Deng, Prof. Jun-Gang
Mu, Dr. Lin
Cheng, Dr. Jun-Hao
Zhang, Dr. Hongfei
Abstract： Unlike ground-state two-proton ($2p$) radioactivity, excited-state $2p$ emission is typically characterized by high decay energy and angular momentum, making it an important probe for studying the nuclear structure of extremely proton-rich nuclei. However, describing excited-state $2p$ radioactivity half-lives also poses a challenge to theoretical models. To examine whether the generalized liquid drop model (GLDM) with the improved proximity energy (Prox. 77-Set 13), optimized using ground-state $2p$ radioactivity experimental data, can be extended to describe excited-state $2p$ radioactivity, this work calculates the half-lives for $^{14}$O$^{*}$, $^{17}$Ne$^{*}$, $^{18}$Ne$^{*}$, $^{29}$S$^{*}$, and $^{94}$Ag$^{*}$. The present calculations are compared with experimental data and calculations obtained from the effective liquid drop model (ELDM), the unified fission model (UFM), and the Coulomb and proximity potential model (CPPM). The results calculated by this work are in good agreement with both the experimental data and the results of other theoretical models, validating the applicability of the GLDM with improved proximity energy for describing excited-state $2p$ radioactivity. This work also systematically investigates the dependence of excited-state $2p$ radioactivity half-life on decay energy and angular momentum, which will shed new light on the properties of exotic proton-rich nuclei.
Peer Review Status:Awaiting Review
Subjects: Physics >> Nuclear Physics submitted time 2026-04-20
Abstract： As critical sensing components in industrial automation and control systems, electronic sensors are prone to performance degradation and drift faults due to harsh operating environments. Among these, minor drift faults are characterized by slow variation and weak early-stage features, making them difficult to detect promptly using conventional methods. Once accumulated to a detectable level, such faults pose serious threats to system safety and operational stability. To address this issue, this paper proposes a sensor drift fault detection and data reconstruction method based on sequence-to-sequence model and principal component analysis (Seq2Seq-PCA). The method first selects auxiliary variables through Spearman correlation analysis to construct the input feature set. A Seq2Seq model with an attention mechanism is then employed for multi-step rolling prediction to capture the dynamic characteristics of the system. Principal component analysis is applied to the prediction residuals to establish a statistical monitoring model, enabling sensitive detection of minor drift faults. Upon fault detection, the multi-step prediction values of the Seq2Seq model are directly used as the reconstructed output, achieving seamless integration of fault detection and data reconstruction. Experimental results on the nuclear power plant simulator demonstrate that the proposed method achieves accurate detection and reliable reconstruction under various drift rates.
Peer Review Status:Awaiting Review
Subjects: Nuclear Science and Technology >> Particle Accelerator submitted time 2026-04-20
Abstract： This study addresses the demand for high-performance linear injectors in proton‑α particle integrated tumor therapy platforms and presents the beam dynamics design of a 220 MHz α particle Radio Frequency Quadrupole (RFQ) accelerator. To further minimize the longitudinal emittance obtained from the default ParmteqM design tool and satisfy the acceptance requirements of subsequent accelerating structures, an independent RFQ parameter design program is developed using Mathematica software. This program implements a "two-section shaper" strategy for the shaper section, achieving precise control over the bunching process through piecewise linear modulation of the evolution rates for the synchronous phase and the modulation factor. Dynamics simulation results demonstrate that the optimized design reaches a beam transmission efficiency as high as 98.1%. Notably, the exit longitudinal rms emittance is reduced by nearly 50% compared to the original scheme, significantly enhancing beam quality. A 3D model of cavity is constructed and simulated by using CST Microwave Studio. The results show the cavity exhibits Kp of 1.79 and Q0 of 13225. A total tuning range of tuners is -1.1 to 1.5 MHz. Through the collaborative regulation of end undercuts and tuners, the field unflatness across quadrants is strictly maintained within ±0.5%. Finally, multi-particle tracking is performed via TraceWin software. The verification results indicate that the beam transport performance based on the calculated 3D electromagnetic fields is in well agreement with the ParmteqM simulation results, confirming the self-consistency and reliability of the overall design.
Subjects: Nuclear Science and Technology >> Radiation Physics and Technology submitted time 2026-04-20
Shi-Yu Zhang
Yang-Bo Nie
Yan-Yan Ding
Qi Zhao
Kuo-Zhi Xu
Xin-Yi Pan
Xiao-Yu Wang
Bei-Bo He
Hong-Tao Chen
Qi Sun
Zheng Wei
Abstract： Accurate nuclear data for neutron interactions with bismuth are crucial for applications in nuclear technology and radiation protection. This paper presents a comprehensive benchmark analysis that compares experimental data obtained at multiple angles and thicknesses with simulations based on four nuclear-data libraries: CENDL 3.2, ENDF/B-VIII.0, JENDL-5, and JEFF-3.3. The experiments involved neutron-leakage measurements of bis muth at three thicknesses and six angles, along with standard sample validations. Pulse time distributions were reconstructed using the maximum likelihood expectation maximization algorithm, and a silicon-carbide detector was employed to accurately distinguish between deuterium–tritium and deuterium–deuterium reaction products. Simulation models validated using polyethylene-sample results demonstrated calculated-to-experimental (C/E) values of 1 ± 0.03, thus confirming their reliability. The analysis revealed that CENDL-3.2 exhibited the best overall agreement in the elastic scattering region. In the discrete inelastic scattering region, JENDL-5 performed best at larger angles, while JEFF-3.3 was more accurate at smaller angles. In the continuous inelastic scatter ing region, JEFF-3.3 demonstrated the best overall performance, with CENDL-3.2 achieving good agreement at selected angles. In the (n,2n) reaction region, ENDF/B-VIII.0 provided C/E values closest to unity, while JENDL-5 ensured better consistency across the full energy spectrum. These findings highlight the importance of selecting appropriate nuclear-data libraries and emphasize the necessity for ongoing data refinement to im prove modeling accuracy.
Subjects: Physics >> Nuclear Physics submitted time 2026-04-20
Yang, Mr. jicong
Li, Dr. Xiaolong
Guo, Prof. Qi
Feng, Mrs. Jie
Zheng, Dr. Qiwen
lin, Mr. wen
Li, Prof. Yudong
Abstract： Commercial Off-The-Shelf (COTS) devices are widely used in aerospace electronic systems, but their process design does not meet the application requirements of the space radiation environment, leading to performance degradation risks caused by Total Ionizing Dose (TID) effects. However, traditional sampling-average radiation hardness (RH) assessment methods are costly and time-consuming, and fail to effectively address lot-to-lot and within-lot fluctuations in the RH consistency of COTS devices. This paper proposes a machine learning model based on physical feature enhancement. A high-quality dataset is constructed via irradiation experiments on devices from multiple manufacturers and lots. By introducing electrical parameter responses under multiple electrical stress conditions as enhanced feature parameters, the model realizes non-destructive identification of device manufacturing processes and prediction of total-dose radiation degradation. Results show that the model achieves identification accuracy of approximately 0.965 for device manufacturers and 0.842 for lots; at four specific dose points, the coefficient of determination (R²) for radiation degradation prediction is above 0.838, outperforming the sampling-average prediction method. Incorporating electrical parameter responses under multiple electrical stress conditions improves the model’s performance in manufacturing process identification and TID radiation degradation prediction. This study reveals that differences in the pre-irradiation initial electrical parameters of devices have an implicit correlation with their radiation hardness characteristics. Compared with a single test condition, the responses of device parameters to multiple electrical stresses contain richer RH feature information. In addition, the model is verified to have certain generalization ability on new lot samples not included in the training set. This method provides a new approach for the efficient screening and assessment of the radiation hardness of COTS devices.
Peer Review Status:Awaiting Review
Subjects: Physics >> Nuclear Physics submitted time 2026-04-20
Li, Dr. Guo
Shi, Prof. Jian-Rong
Zhang, Dr. Suyalatu 张苏雅拉吐
Yan, Prof. Hong-Liang
Chen, Prof. Yong-Shou
Abstract： The post-asymptotic giant branch (post-AGB) star IRAS 14325-6428 exhibits a peculiar heavy-element abundance pattern, characterized by a high [Ba/La] ratio and an anomalous odd-isotope Ba ratio (f_odd,ba=0.25±0.08), which is difficult to explain via the classical slow neutron-capture process (s-process). In this work, we theoretically investigate this abundance pattern by considering intermediate neutron-capture process (i-process) nucelosyntheis. We employ a self-consistent computational framework. A stellar model representative of the progenitor (1.5 M_sun, Z = 0.003) is evolved with MESA to the thermally pulsing AGB phase to obtain intershell elemental abundances. These values are then used as input for i-process nucleosynthesis calculations performed with a one-zone network (NucNet Tools) at constant temperature and density. The observed heavy-element abundances are best reproduced by a model with neutron density N_n = 5×10^13 cm^-3 and neutron exposure τ = 1.4 mbarn^-1, followed by dilution with a scaled-solar composition. This model reproduces the high [Ba/La] and [Ba/Ce] ratios and yields a post-dilution odd-isotop fraction f_odd,ba = 0.51, consistent with the observational trend. The abundance pattern arises from the i-process path approaching the neutron magic number N = 82, where the flow slows and the material accumulates at 135I, which subsequently β- decays to 135Ba. This leads to enhanced Ba production and reduced synthesis of heavier species. These results, consistent with the star's multi-element classification as enriched in both s- and r-process elements, provide quantitative support for an i-process origin of the heavy elements in IRAS 14325-6428, likely triggered by a relatively short-lived proton-ingestion episode in its AGB progenitor.
Peer Review Status:Awaiting Review
Subjects: Physics >> Nuclear Physics submitted time 2026-04-19
Strizhak, Dr. Alexander
Ivashkin, Dr. Aleksandr
Baranov, Mr. Alexander
Musin, Mr. Sultan
Tkachev, Dr. Igor
Abstract： The possibility to use the SrI2(Eu) scintillator for detection of tritium neutrino with energy below 20 keV is suggested. SrI2(Eu) scintillator has a record light yield up to 120 photons/keV that in combination with high photon detection efficiency photodetectors would enable the detection threshold below 1 keV. The compact modular setup of SrI2(Eu) scintillation detectors to register sub-keV energy deposition from neutrinos interactions is considered. Each individual detector module comprises four small scintillators with attached SiPM arrays packed together in a light-tight plastic case. The main drawback of SiPM, the high dark current rate (DCR), which is exponentially dependent on temperature, can be suppressed at negative operating temperatures. The experimental tests of SiPMs were performed over a wide temperature range from +20°C to -65°C,that show the DRC reduction for about three orders. To further suppress the effect of DCR, a time coincidences of the signals in each detector module were implemented. The light collection of SrI2(Eu) scintillators with SiPM readout was studied using several γ-ray sources. The optimal operating conditions were examined to provide a minimum energy detection threshold. The normalized light collection achieves 26.3 photoelectron/keV in all range of measured energies. The performed tests with low energy γ-ray sources confirmed that constructed SrI2(Eu) modules are suitable for high-resolution X- and γ-rays spectroscopy.
Peer Review Status:Awaiting Review
Subjects: Physics >> Nuclear Physics submitted time 2026-04-18
于, Dr. 鸿翔
Zhou, Dr. Chong
Fu, Dr. Yao
yang, Dr. yi-ang
Wang, Mr. Shanwu
Xue, Dr. Shuaiyu
deng, Dr. hui
Abstract： Molten salts are efficient heat-transfer and storage media widely used in advanced energy systems, including nuclear and concentrated solar power. Their high melting points, however, can induce transient pipeline freezing, impairing operational economy and compromising flow safety. This study employs an integrated multiscale CFD and lumped-parameter approach to systematically investigate the complex freezing process of molten salt in pipes and to quantify the effect of key boundary conditions. Under pumped-inlet conditions, the characteristic temperature and flow rate exhibit a distinct dynamic: an initial decrease, followed by recovery and stabilization, marking the transition from initial filling to steady flow. Excessively designed cooling systems can drive the heat removal rate beyond a safe threshold. The risk of pipe blockage rises substantially for values of the dimensionless freezing parameter θ ≤ 1. The model's applicability is examined, and a parametric sensitivity analysis assesses the influence of inlet temperature, flow velocity, cooling intensity, pipe length, and wall thickness. This work provides a theoretical basis and safety-design guidelines for freeze-protection in molten salt cooling systems.
Peer Review Status:Awaiting Review
Subjects: Nuclear Science and Technology >> Particle Accelerator submitted time 2026-04-16
Abstract： [Background]: X-ray transmission (XRT) sorting technology can improve the concentration of target minerals, thereby enhancing resource utilization and production efficiency. However, in practice, ore images often exhibit adhesion and deep overlapping, leading to sorting errors and resource waste. [Purpose]:To address this, a shape and density compensation algorithm is proposed for deeply overlapping ore images with pronounced shadow regions. [Methods]:The method employs a region-growing algorithm to extract binary images of overlapping areas, which are then combined with individual ore binary images via a logical OR operation to restore ore shapes. Density compensation is performed using contour lines based on varying circumscribed circle radii. [Results]:Experimental results show that the processed ore images better approximate actual shapes and density values. Compared with uncorrected images, the centroid accuracy improves by 73.58%, average density compensation in overlapping areas reaches 91.35%, and similarity to real ore structures increases by 82.71%. [Conclusions]:The proposed method effectively enhances shape restoration and density compensation, significantly improving mineral sorting efficiency.
Subjects: Physics >> Nuclear Physics submitted time 2026-04-16
Yu, Miss Jiachen
Li, Mr. Kaihang
Gu, Mr. Jingfan
Cai, Mr. Chang
Chen, Mr. Jiangyu
Dai, Mr. Huayu
Fang, Dr. Rundong
Gao, Mr. Hongrui
Gao, Prof. Fei
Guo, Mr. Xiaoran
Guo, Mr. Jiheng
Jia, Mr. Chengjie
Hao, Mr. Yanzhou
Han, Mr. Xu
Lei, Mr. Yang
Li, Dr. Shenchao
Li, Mr. Siyin
Lin, Prof. Qing
Liu, Dr. Jiajun
Ren, Miss Yuanyuan
Abstract： The RELICS (REactor neutrino LIquid xenon Coherent elastic Scattering) experiment employs a dual-phase liquid xenon time projection chamber to search for Coherent Elastic Neutrino-Nucleus Scattering (CEνNS) induced by reactor neutrinos. To detect these sub-keV nuclear recoils and minimize signal attenuation, it is critical to maintain a sufficiently low impurity concentration in the detector. This work presents a comprehensive purity evolution model developed to describe impurity migration inside the detector. Utilizing measured material outgassing rates as input parameters, the model incorporates non-uniform transport mechanisms of the impurities, including circulation, vaporization, and condensation. The model is validated using data from a dedicated prototype detector. Based on this validated model, projections for the purification performance of the upcoming RELICS-10 and RELICS-50 detectors are provided.
Peer Review Status:Awaiting Review
Subjects: Physics >> Nuclear Physics submitted time 2026-04-16
Abstract： We study the generation and space-time evolution of fluid acceleration in heavy-ion collisions using AMPT and UrQMD transport models combined with a Gaussian smearing method. The peak proper acceleration reaches several hundred MeV, with mild model dependence. Transverse acceleration points outward and is strongest at the fireball boundary due to steep pressure gradients and low enthalpy density—a persistent feature even at early times and low energies. Longitudinal acceleration shows strong collision-energy dependence: low-energy collisions exhibit early deceleration from nuclear stopping, while ultra-relativistic collisions produce sharp acceleration pulses from passing nuclei. The volume-averaged acceleration is nearly centrality independent, as extreme acceleration localizes at boundaries. These strong acceleration fields may have important implications for QGP physics, including the Unruh effect mimicking a thermal bath, potential influences on the chiral phase transition and deconfinement, and contributions to spin polarization beyond vorticity.
Peer Review Status:Awaiting Review
Subjects: Nuclear Science and Technology >> Radiation Physics and Technology submitted time 2026-04-16
Abstract： All 120 dipole magnets in the Hefei Advanced Light Facility (HALF) storage ring are electromagnetic longitudinal gradient bend magnets with variable gaps. The precise measurement of their integral field and uniformity is crucial for ensuring beam quality. To meet the demand for efficient, high-precision measurement of these magnets in large quantities, HALF has developed a long moving coil magnetic field measurement system.The system features a uniquely designed double-layer measurement coil, enabling the simultaneous acquisition of integral field and uniformity data from two vertical planes within the magnet aperture during a single scan. It also incorporates an automated measurement function, allowing for automatic standardized magnet excitation cycles and sequential testing at pre-programmed excitation currents.Test results demonstrate that the measurement repeatability for the integral field is better than 1×10⁻⁴, and for field uniformity, better than 5×10⁻⁵, which is superior to the typical 10⁻⁴ level achieved by the Hall probe method. The successful development of this system provides a reliable technical solution for the batch testing of HALF's dipole magnets, holding substantial value for engineering applications.
Subjects: Nuclear Science and Technology >> Radiation Physics and Technology submitted time 2026-04-16
Abstract： To meet the requirements of the electron cooling system for the China Electron–Ion Collider regarding high bunch charge, high repetition rate, long pulse length, low emittance, and low energy spread in the electron beam source, this paper proposes a front-end physics design scheme based on an energy recovery linac. Beam dynamics simulations and optimization studies are conducted, focusing on two core challenges: strong space charge effects and high-order nonlinear coupling. The injector employs a synergistic configuration comprising a 162.5 MHz quarter-wave superconducting RF photocathode electron gun, a 650 MHz buncher cavity, a two-cell 650MHz booster cavity, and a two-cell 1.95 GHz third harmonic cavity. A genetic algorithm is applied for global optimization of parameters such as laser spot size, pulse length, cavity phase and gradient, and solenoid magnetic field. Four typical merger section configurations are evaluated comparatively, revealing the physical mechanism by which the synergy between second-order path length coefficient and longitudinal charge density gradient leads to emittance growth in the merger section. The main accelerator section adopts a three-cavity module design. The 180° bending section in the return beamline utilizes a symmetric multi-magnet configuration to suppress high-order aberrations, while the path length adjustment section is used solely for phase matching. Results indicate that at the injector exit, the beam energy reaches 3.5 MeV, with a normalized emittance of 1.4 mm·mrad and a relative energy spread of 0.46‰. Among the merger configurations, the multi-magnet small-angle bending scheme exhibits the minimal emittance growth. At the main accelerator exit, the beam energy is 10.4 MeV, with an emittance of 2.5 mm·mrad and an energy spread of 0.47‰. Phase adjustment in the return beamline yields a theoretical energy recovery efficiency approaching 100%. Global simulations demonstrate that the beam parameters at the cooling section entrance meet the design objectives. This study demonstrates the feasibility of the physical design of an ERL under high-charge, long-bunch parameters, providing critical insights for the development of the ERL-based electron cooler for the future Electron-ion Collider in China.
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