To address the challenges of difficult feature extraction and suboptimal parameter configuration for cyclotron ion source fault diagnosis in complex environments, this study proposes an intelligent diagnostic framework integrating Kernel Principal Component Analysis (KPCA), an Improved Sparrow Search Algorithm (ISSA), and a Support Vector Machine (SVM). The KPCA algorithm is employed for dimensionality reduction to handle the highly nonlinear nature of fault data. Regarding algorithmic evolution, the basic SSA is enhanced by integrating dynamic weights, opposition-based learning, and Cauchy mutation strategies, which effectively overcome the diagnostic bottlenecks inherent in cyclotron scenarios. Furthermore, the ISSA facilitates the global adaptive optimization of key SVM parameters, eliminating the stochasticity of empirical tuning and fundamentally enhancing the model’s robustness. Experimental results across 30 independent tests demonstrate that the KPCA-ISSA-SVM model achieves an average accuracy of 97.6% in multi-class fault detection. Compared with other classic diagnostic models, the proposed framework exhibits superior precision and stability, providing an effective technical approach with significant engineering value for the precise monitoring of ion source statuses.

The China Institute of Atomic Energy (CIAE) is developing a proton cyclotron with an energy of 9.5 MeV and a current of 100 mu A. To evaluate the performance of the cyclotron, the beam dynamics study has been conducted. Static and dynamic orbit analyses combined with phase-space matching were used to assess its beam acceptance and acceleration capability. Particle tracking simulations were employed to calculate characteristics such as radial centering and axial focusing, and the structure was optimized accordingly. The extracted beam parameters were controlled by adjusting the tilt angle of the stripping foil. The phase acceptance of this cyclotron exceeds 60 degrees, and the beam size at the liquid target is 1.35 mm & times; 2.01 mm. The cyclotron has entered the beam commissioning stage, with measured beam currents of 107 mu A at the internal target and 65 & micro;A of extracted beam current at the Faraday cup after stripping.

Beam prediction is pivotal for the stable operation of accelerators, as a stable beam enhances the therapeutic efficacy of Boron Neutron Capture Therapy (BNCT) devices, the efficiency of radioisotope production, and the resolution of neutron imaging. During long-term operation, beam characteristics exhibit nonlinearity and time-dependency as the state of the accelerator evolves over time. To address this, a hybrid beam prediction model is proposed based on Convolutional Neural Networks (CNN), Long Short-Term Memory (LSTM), and an Attention mechanism. Specifically, the CNN extracts spatial features from beam data, the LSTM captures long-term dependencies within the time series, and the Attention mechanism focuses on critical beam information to achieve high-precision forecasting. Experimental results demonstrate a Mean Absolute Error (MAE) of 2.86 % and a Mean Squared Error (MSE) of 0.48 %. These results prove that the proposed model effectively handles the complexity and dynamics of beam data, providing a robust reference for accelerator beam control.

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.

Magnetic field shimming is crucial for achieving isochronous acceleration in a cyclotron. Matrix methods based on least square fitting are commonly used to calculate the cutting curve of a shimming bar. However, this matrix method becomes inapplicable when dealing with cases of nonlinear shimming effects. An algorithm based on the Gauss-Newton iteration method to address shimming problems with nonlinear effects has been proposed. Numerical and experimental results demonstrate the effectiveness and accuracy of this algorithm. It has been applied to a compact positron emission tomography (PET) cyclotron developed at China Institute of Atomic Energy (CIAE).

As the research work about irradiation effect and neutron measurement requires high-energy neutron with the development in the fields of space exploration, medical treatment and high-energy physics investigation, a beamline of quasi-monoenergetic neutron in the range of 30 similar to 50 MeV based on a proton cyclotron with a maximum energy of 50 MeV is under construction and preparation. We studied the design of this quasi-monoenergetic neutron beamline with a focus on target chamber and collimator. Comprehensive comparison on characters of thermodynamic and nuclear physics between lithium and beryllium was conducted, and lithium was chosen as target material by better performance on quasi-monoenergetic neutron peak. Relevant parametric simulations of lithium thickness were carried out in consideration of efficiency and quality of neutron generation which shows the change on height and width of quasi-monoenergetic neutron peak. Energy loss of incident proton caused by titanium film and argon gas was estimated to provide a reference for the mechanical design of target chamber. Evaluation has been done to show the variation of neutron spectra and fluxes at different positions from the target along with collimators of different lengths, and the collimator length was determined to be 2 m in view of flux and ratio of quasi-monoenergetic neutron peak. All work provides a data reference for the building and operation of the quasi-monoenergetic neutron beamline.

A set of nozzle equipment for proton therapy is currently under development at China Institute of Atomic Energy (CIAE). To facilitate the off-line commissioning of the whole equipment, a set of ionization chamber signal generation system, known as the test electronics, was designed. The results showed that the system can simulate the beam position, beam fluence (which exhibits a positive correlation with the dose), and other related analog signals generated by the proton beam when it traverses the ionization chamber. Moreover, the accuracy of the simulated beam position is within ± 0.33 mm, and the accuracy of the simulated beam fluence signal is within ± 1%. The test electronics can output analog signals representing environmental parameters. The test electronics meets the design requirements, which can be used for the commissioning of the nozzle system as well as the treatment control system without the presence of the proton beam.

Cyclotrons are indispensable scientific equipment and platforms for cutting-edge research and are widely applied in nuclear science and life science, as well as the innovative development of nuclear technology. The difficulties and corresponding key technologies of compact high-intensity proton cyclotron research are fourfold: the insufficient axial focusing force of a compact cyclotron frustrates improvements in beam energy and beam intensity; the smelting capacity of large-scale magnets and modern manufacturing restricts magnetic field accuracy, which affects the dynamic performance of high-intensity beams; high-beam dynamic loads and coupling resonance considerably influence the stable operation of cyclotrons; and high-intensity negative hydrogen ion sources, the coupling of multiple physical fields in the narrow space of the central region, and the high-precision six-dimensional matching of beam optics in the extraction region are also great challenges for compact high-intensity cyclotrons. To solve these problems, a strong focusing theory of radially modulated magnetic field gradients was innovatively created by a cyclotron team at the China Institute of Atomic Energy (CIAE), and a parallel computing algorithm and software for multi-cluster high-intensity beam dynamics were also invented. These innovations extend the acceleration energy limit of compact cyclotrons and help increase beam intensity substantially under the restriction of space charges. A magnet shimming algorithm for isochronous fields and nonideal harmonic fields, based on the shape function of odd and even triangles, was developed to improve axial focusing effectively and solve problems in magnet engineering. Key RF technologies, such as suppression of "transmission line-resonator" system coupling oscillation and dynamic loading changes, were researched, and then a long-term operation with high stability was achieved for the entire machine. A high-intensity cyclotron prototype with strong focusing was built based on these innovations, effectively promoting the beam intensity of miniaturized cyclotrons from 50-100 mu A to 300-500 mu A. Subsequently, more than ten high-intensity compact cyclotrons have been developed at the CIAE, and these cyclotrons can provide beam intensity at the mA order after necessary upgrades. The main performance indexes of the cyclotrons, such as intensity, injection efficiency, and extraction efficiency, are world-class. Cyclotron applications are also applied in the projects of the CIAE, National Space Science Center, Irradiation Hardening Application Technology Innovation Center, and Peking University and contribute much to scientific research. We provide proton beams for similar to 100 units to perform scientific and technological research related to nuclear technology and its applications. The research and applications prompt the development of high-intensity proton cyclotrons.

GeV-class proton beam with an average power of several megawatts has many important applications in particle physics towards the intensity frontier, as well as in the advanced energy and material science. There are three different types of constructed accelerators for high power proton beam production: The cyclotron, linear accelerator and rapid-cycling synchrotron. The highest beam power of these accelerators currently is 1.4 MW. Studies have shown that the energy efficiency of the PSI cyclotron is about two times of the other types. Thus, the isochronous accelerator is a good technical route to develop proton machines with high beam power and high power efficiency. The isochronous fixed-field alternating gradient accelerators (FFAGs) scheme is a promising candidate for next-generation GeV-class high power proton driver. There are two bottle-neck problems in the development of GeV/mA class FFAG: As an isochronous accelerator, radial tune of isochronous FFAG is approximately increasing with beam energy in a linear way, and thus the integer resonance crossing problem becomes an inevitable problem. Single turn extraction with very low beam losses is also a verry important issue of high power isochronous FFAG. To the author’s knowledge, high beam extraction efficiency for beam energy of GeV-class is still unresolved. To solve those problems, an idea of integer resonance suppressor (IRS) which intentionally introduces the third harmonic magnetic field was proposed. One IRS is made up of two pair of coils, and each pair has independent power supply to generate the required harmonic magnetic bump. IRS can not only inhibit the radial oscillation and beam size blowup caused by integer resonance crossing but also contribute to a controllable coherent oscillation which is helpful to beam extraction with high efficiency. In the CYCIAE-FFAG design, νr=3 resonance is the lowest order resonance. Third harmonic field of only 1 Gs (1 Gs=10-4 T) can drive large coherent oscillation and then the following intrinsic resonance 3νr=10 will lead to serious beam size blowup effect. However, IRS can compensate the driving error and minimize the coherent oscillation before reaching the detrimental resonance. IRS provides a possibility of relaxing the requirement of magnet manufacture and installation. Our simulations show that third harmonic field of 10 Gs is acceptable with proper IRS settings. In the PSI 590 MeV ring cyclotron, beam is eccentrically injected to give rise to coherent oscillation. However, in CIAE-FFAG design, the beam was injected centrally and controllable amplitude of coherent oscillation was introduced in the integer resonance crossing process. The IRS scheme makes it possible to have knobs to adjust the amplitude and phase of coherent oscillation, which will be much easier to enlarge the turn separation. Taking the CYCIAE-FFAG project for example, simulations in this paper show that IRS can not only reduce the beam size growth rate to less than 5%, but also enlarge the turn separation to 3 cm. That is to say, IRS not only acts as resonance suppressor, but also plays the role of separation optimizer between the last and second last turn. The result shows that IRS is a potential solution for resonance crossing and extraction problems of GeV/mA class circular accelerator.

The compact high-intensity proton cyclotron based on the stripping-extraction method has made great progress and obtained huge applications since the first cyclotron was applicated in 1932 in the world, especially in the field of nuclear medicine. China Institute of Atomic Energy (CIAE) built a 30 MeV compact high-intensity proton cyclotron in the 1990s in China and a series of compact high-intensity proton cyclotrons with energy of 10 MeV, 14 MeV, 100 MeV, 14 MeV/1 mA used in boron neutron capture therapy (BNCT) based on the stripping extraction technology have been developed. The 100 MeV compact high-intensity proton cyclotron (CYCIAE-100) built in 2014 is the largest compact high-intensity proton cyclotron with the higher energy in the world with a maximum current intensity of 520 μA and a beam power of 52 kW. The BNCT cyclotron is also the first high-intensity proton cyclotron with extracted beam reaching the mA level in China. A great progress on the stripping extraction technology used in cyclotrons has been achieved at CIAE during the 60 years development. The codes for stripping extraction studies, such as CYCTR, GOBLIN, STRIP-UBC and COMA, are developed by CIAE too. The study method with the code of GOBLIN for the beam dispersion effect in the stripping extraction cyclotrons was given in detail. The influence of the angle between the stripping foil and the beam to the quality of the extracted beam was analyzed in the paper. The single-turn stripping extraction technology for some special application was used in the stripping extraction cyclotrons. The stripping efficiency and the life of stripping foils were studied in the paper. The beam loss control in the stripping extraction field and stripping probe system were introduced in the end.

中国原子能科学研究院目前正在研制用于硼中子俘获治疗(BNCT)的强流质子回旋加速器,该加速器设计引出能量14 MeV、质子束流强大于1 mA.相比引出流强为400μA的PET回旋加速器,BNCT强流质子回旋加速器对中心区相位接收度和轴向聚焦的要求更高.为实现mA量级的束流的加速和引出,BNCT强流质子回旋加速器采取了增加负氢束流注入能量、增大磁铁镶条孔径、使用用于增大D ee盒头部张角的阶梯状结构及调整加速间隙的入口和出口高度等一系列中心区结构优化设计,有效地提高了中心区的相位接收度,改善了轴向电聚焦.在新的离子源注入能量下通过数值计算得到实测场下的轴向电聚焦和间隙高度的关系,选取合适的间隙高度获得最佳的轴向聚焦,从而确定了mA量级束流的注入和加速的中心区结构.同时在设计中考虑空间电荷效应的影响,计算了不同流强下的束流尺寸变化.中心区结构在实测磁场下的优化设计计算结果表明,BNCT强流质子回旋加速器中心区的束流对中好于0.5 mm,相位接收度大于40°,中心区最高可接收流强3 mA.目前,新的中心区结构已进入机械加工阶段.

在230MeV超导回旋加速器调束的过程中,需要对束流的大小形状和对中情况进行测量分析,束流测量装置可以满足上述要求.本装置利用径向靶和包络靶可以测量半径150mm到850mm范围内的束流,采用了双X型圈密封结构,大大缩短了径向空间,密封性能好.直线驱动装置运动平稳可靠,靶杆带动靶头运动精度高,可为后续的束流测量装置的设计提供参考依据.

China Institute of Atomic Energy (CIAE) is constructing a high current cyclotron-based boron neutron capture therapy (BNCT) system. The designed proton beam intensity of this cyclotron is 1 mA. The RF system of the cyclotron consists of two separate cavities, two 20-kW amplifiers, a 300-W amplifier for the buncher, and one low-level radio frequency (LLRF) system. The LLRF system controls the amplitudes and phases of the two independent cavities and the buncher. The previous analog–digital hybrid LLRF system in CIAE was designed for low beam loading applications. As during the beam commissioning and machine operation, the RF system requires a more powerful, flexible, and reliable real-time LLRF system, the LLRF group decides to design a new LLRF system for this application. At TRIUMF, a digital LLRF system was developed for the prebuncher of the ARIEL project. This state-of-the-art design is extended and utilized for the BNCT LLRF system. In which, the amplitude and phase of the two separate Dees, as well as the buncher for beam injection, will be regulated by a single field-programmable gate array (FPGA). For such a demanding control task, the design shows a promising future, both from real-time response and flexibility points of view. The design ideas, technology features, system structure, hardware and software development, and the desktop test will be presented.

In China, there is a strong demand of the medium-energy proton accelerators for proton therapy. A compact superconducting cyclotron named CYCIAE-230 is currently under construction at CIAE to provide 230 MeV proton beam. In this paper, the investigation and quantitative simulation of beam physics for CYCIAE-230 will be presented in detail, which mainly include: 1. The beam dynamics behavior in the ultra compact central region and the design challenges including the micro PIG ion source, the tips of magnetic poles and RF cavities; 2. the numerical simulation and optimization of the phase slip and tune diagram in acceleration region; 3. the orbit simulation in the extraction region, emphasizing on increasing the turn separation and the resonance study; 4. the fast intensity modulation, control of beam stabilization by a closed-loop feedback, and the basic algorithm for controlling the beam intensity, adjusting the phase and their implementations.

目前,中国原子能科学研究院已研发出适用于PET的小型回旋加速器CYCIAE-14,为适应医院单独使用及即时药物配送中心的需求,本文对CYCIAE-14加速器开展了工程化 、标准化研究:将离子源和注入线由安装于加速器上方改为下方,使加速器实现自屏蔽结构;主励磁线圈由原来几十路水电接头改为两路,提高可靠性;所有电源采用工程化设计,减小电源体积,实现紧凑 、使用便捷 、信号控制快速传输的功能;主真空统一采用冷泵,保证真空室的洁净度;所有线缆布置规范化 、工程化;水路管道标准化 、接头快捷 、统一;生产靶采用大体积 、高效率结构,实现国产化.并在上述工程化 、标准化技术研究与实践的基础上,制定 、颁布了国标GB/T 34127—2017,为我国核医学"一县一科"的普及发展起助推作用.

There are very strong demand for mid-energy of proton machine recent years due to the surging cancer patients and fast progress of the space science in China. For the applications of proton therapy and proton irradiation, the energy range of proton beam usually is from 200 MeV to 250 MeV, or even higher for astronavigation. Based on the R&D starting from 2009, two construction projects of 230 MeV and 250 MeV superconducting cyclotron, which have been implemented recently at China Institute of Atomic Energy(CIAE). That was started in Jan 2015 for the 230 MeV machine, for the program of proton therapy and space science launched by China National Nuclear Corporation (CNNC), and in Jan 2016 for the 250 MeV machine, for the program of proton therapy launched by the Ministry of Science and Technology of China (MOST). In this paper, the designs for the two SC cyclotrons and their key components, including the main magnet, SC coils, RF system, internal ion source and central region, extraction system, etc, and the construction progress of the machines will be presented.

100 MeV强流质子回旋加速器(CYCIAE-100)加速H-,引出质子束能量为75～100 MeV、最大柬流强度为200 μA.为对束流输运线上的质子束流强度进行无阻挡实时监测,选择了直流流强监测器(DCCT),其在设计上考虑了空间限制、杂散磁场和外部高频干扰信号等因素对探头的影响.探头外采用了三重磁屏蔽设计,磁屏蔽外为1层黄铜的电屏蔽.采用了绝缘垫圈隔断束流输运线的直流导电性,束流输运线管壁通有冷却水以保证探头温度稳定.在绝缘垫圈处增加电容以满足探头对电容值的要求.采用高精度PLC-AI模块对DCCT的输出电压进行了读取.通过模拟束流的实验验证表明,DCCT设计合理可行,测量结果的线性度、误差等指标符合设计要求.