The PREF project (Proton Radiation Effects Facility) aims to provide low to medium energy protons from 10 – 60 MeV, which is an excellent range for experimental research on the displacement damage effect studies of satellites and payload components, and is currently under construction in China. Average proton beam fluxes range from tens of particles/(cm2s) up to approximately 108 particles/(cm2s), spot sizes after scanning range from 2 × 2 cm2 to 20 × 20 cm2, and uniformity is better than 95%. It comprises a 2.45 GHz ion source, a 325 MHz four-vane RFQ linac injector, a compact synchrotron, and two irradiation terminals. Protons will be injected into synchrotron using multi-turn injection scheme to obtain high-gain beam accumulation. The third-order resonance slow extraction scheme is adopted to achieve high efficiency and continuous uniform extraction of the beam for irradiation experiments. Several innovative accelerator technologies such as titanium alloy lined thin-wall vacuum chamber and fast ramping rate full energy storage power supply are also adopted. In this paper, the general design and simulation results of the accelerator complex are presented, and the new technology and progress of the PREF project are briefly introduced.

The 300 MeV proton and heavy ion accelerator complex, which is the key part of SESRI (Space Environment Simulation and Research Infrastructure) project, is currently under construction in China. It comprises an 18 GHz high charge-state ion source, a 108.48 MHz cascaded linac injector consisting of a four-rod RFQ and three interdigital H-mode drift tube linacs, a compact synchrotron, and three irradiation terminals. The extensive ion species from proton to 209Bi32+ will be injected into the synchrotron using multi-turn injection method. The third-order resonance and RF-knockout extraction scheme is adopted to provide quasi-continuous spill for irradiation experiments. The general design of the accelerator complex and simulation results are discussed in this paper.

As many diverse accelerator facilities are designed, constructed and operated by IMP (Institute of Modern Physics, Chinese Academy of Sciences), the existing physics control system cannot cover all requirements of these facilities. In order to save the construction time, improve the commissioning efficiency, simplify the operation and reach higher beam intensity and better beam quality, a new physics control system, PACS (Physics-oriented Accelerator Control System), is proposed, designed and implemented in the IMP. With the control layer in three layers, i.e. application layer, physics layer and control layer, the PACS is protocol neutral and can be deployed to all accelerator facilities in the IMP without massive reprogramming. The physics layer encapsulates all physics control processes, including device-level physics and system-level physics, into highly usable interfaces, which makes the development of the application layer and the customized applications simpler, more robust and efficient. Due to the OOP (Object-oriented Programming) technology used in this layer and specific designs, the PACS is highly scalable and can keep pace with the rapidly changing hardware and software. As the application layer is built upon the physics layer interfaces, no matter what is updated in the physics layer, the applications remain unchanged. Many new physics control processes can be tested and implemented in the physics layer by the developers or the users without influencing the operation of these facilities. Now, a version of PACS for miniature facilities is implemented and tested in the CSR, a heavy ion accelerator facility for scientific research in the IMP. It meets the expected goals and provides a solid base for following versions. In the future, the PACS will become a general-purpose physics control system for all heavy ion accelerator facilities.

Transient beam loading effects and microwave instability are very important in ion synchrotrons. A simulation code longitudinal particle tracking code (LPTC) based on multiparticle tracking is developed to simulate the beam loading effects and the longitudinal beam instabilities in the booster ring (BRing) of the High Intensity heavy-ion Accelerator Facility (HIAF). A process of beam capture, acceleration, debunching, and the second capture is simulated with a reference ion beam of Kr-78(19+). The simulation results show that the beam loading effects have major contribution to the beam behavior during the debunching stage and the second capture stage. A feed-forward system is suggested to compensate the beam loading effects, and the main parameters of the feed-forward system are given. The microwave instability of coasting Kr-78(19+) beams is observed from the simulation results. The threshold of the microwave instability is also given. The development of self-bunching and methods to suppress the microwave instability in the BRing are discussed.

Background/Aim: Although vaccination is available, mumps remains a public health concern in many countries including China, where had approximately 260,000 notified cases in 2018. Previous studies have indicated the impact of meteorological factors and mumps, but findings vary across different regions, with limited evidence to inform local public health responses. We aim to examine the impacts of meteorological variables and mumps in Jinan, a temperate city of China.Methods: Weekly meteorological data and notified cases of mumps in Jinan were collected for 2014-2018. Descriptive, correlation and regression analyses using the generalized additive model were performed with considerations of multicollinearity, lag effects, long-term trend and seasonality.Results: A total of 4,141 mumps cases were notified in Jinan during the study period, with peaks in May and June. We found a nonlinear relationship between weekly mean temperature and the number of cases. Between 1.2℃ and 24.5℃, the Excess Risk (ER) of mumps for a 1℃ increase in weekly mean temperature was 3.39% (95%CI: 1.63% to 5.17%) at 0-week lag. The lagged effects could last for 3 weeks. When relative humidity was above 55%, the ER of mumps for 1% increase in humidity was -1.03% (95%CI: -1.76% to -0.30%) at 0-week lag. We did not find significant impact of wind speed on the risk of mumps.Conclusions: There are non-linear relationships between temperature and relative humidity and mumps in the temperate city of China. Findings could be integrated into current early warning systems for mumps in order to protect people's health from the risks of changing climate.

In this paper the closed orbit correction of the Heavy Ion Medical Machine (HIMM) synchrotron is described. Results of simulations and measurements are presented. Consistently with simulations, it is possible to correct the maximum closed orbit distortion of the HIMM synchrotron down to 2.4mm in the horizontal direction and 0.7mm in the vertical one. The errors of dipole magnets, especially the longitudinal alignment errors (Δs), have large impact on the horizontal correction results. A Singular Value Decomposition (SVD) algorithm is adopted for computing the correction. The residual orbits and the effects of reducing the number of singular values are analytically expressed and simulated. In addition, the influences of BPM reading errors as well as corrector setting errors are analyzed. For further optimization, the method to estimate the dipole errors is studied. In the commissioning, the maximum closed orbits at BPMs can also be well corrected to within 1mm through SVD algorithm.

The transverse broadband impedances of major components in the BRing (booster ring) of HIAF (High Intensity Heavy-ion Accelerator Facility) are estimated using the analytical formulas or the wakefield solver in the CST Studio Suite. At low frequency, the transverse broadband impedance model of BRing is Z(1)(H)(omega) = -417.14i k Omega/m(horizontal) and Z(1)(V) (omega) -530.19i k Omega/m(vertical), which are larger than the threshold impedance for the transverse mode-coupling instability. The ceramic rings in the vacuum chamber are the primary source of impedance. With a goal of mitigating the instability by reducing the impedance of ceramic rings, a high conductivity coating is discussed in detail. In addition, a prototype of ceramic rings-loaded thin-wall vacuum chamber is manufactured and the impedance measurements are performed. When ceramic rings are coated by 2 mu m-copper, the CST simulation and experiment results show that the transverse broadband impedance of ceramic rings-loaded thin-wall vacuum chamber can be reduced from Z(1)(H)(omega) = -291.69i k Omega/m and Z(1)(V)(omega) -352.37i k Omega/m to Z(1)(H)(omega) = -46.16i k Omega/m and Z(1)(V)(omega) = -64.56i k Omega/m. Furthermore, in this case the transverse broadband impedance model of BRing is reduced by more than 50% to Z(1)(H)(omega) = -171.61i k Omega/m and Z(1)(V)(omega) = -242.38i k Omega/m.

BRing is the booster ring of the HIAF project in which the beam intensity is designed up to 1.0 × 1011 ppp (238U34+). In order to reach the required intensities, an efficient injection scheme is crucial and the beam loss during injection must not exceed the limits defined by machine protection and dynamic vacuum requirements. An injection scheme called two-plane painting multiturn injection is consequently proposed, which exploits both the horizontal and vertical acceptance of the BRing by a tilted electrostatic septum. The influence of the space charge on the injection process is important for the two-plane multiturn injection scheme which should provide the required intensity with a minimal beam loss. The impact of the space charge on the efficiency of the injection process is investigated using a modified ORBIT code. In order to achieve lower beam loss, the particle swarm algorithm is proposed for a detailed injection optimization with space charge effect. Detailed studies on the two-plane painting multiturn injection scheme and the dependence on the lattice tune, the injected beam current, and the injected beam emittance are also presented. The results provide an important guideline for the design optimization of the injection system for the HIAF-BRing.

High Intensity heavy-ion Accelerator Facility (HIAF) project is being constructed by the Institute of Modern Physics, Chinese Academy of Sciences (IMP, CAS). An in-flight High energy FRagment Separator (HFRS) at HIAF was designed to study the properties of rare isotopes far away from the line of beta stability and their involved nuclear reactions of astrophysics interests. HFRS is a two-stage magnetic system which consists of Pre-Separator and Main-Separator. The maximum magnetic rigidity of 25 Tm was designed in particular for experiments with very neutron-rich rare isotopes beams and studies of hypernuclei and Δ-resonances in exotic nuclei. A dispersive mode and an achromatic mode were designed for different experimental requirements. The HFRS device can be used to separate and purify the rare isotopes produced by the projectile fragmentation of all primary beams up to Uranium or by the projectile fission of Uranium ions via Bρ-ΔE-Bρ method. The detailed HFRS ion-optical design including the first order and the higher order, and the magnet specification were presented in this paper.

The Spectrometer Ring (SRing) is an essential part of the High Intensity heavy-ion Accelerator Facility project (HIAF) in China. It is designed as a multi-functional experimental storage ring, which will be able to operate in three ion optical operation modes. The SRing will be used as a time-of-flight mass spectrometer for short-lived, especially neutron-rich nuclei. It will also be used to collect and cool Rare Isotope Beams (RIBs) or highly-charged stable ion beams for nuclear and atomic physics experiments. The design magnetic rigidity is in the range 1.5 to 15 Tm. The beam cooling system consists of stochastic cooling and electron cooling devices. With a help of an electron cooler, stored ions will be decelerated to a minimum energy of 30 MeV/u by RF cavities. The extraction system of the SRing will allow cooled ion beams to be extracted to an external target for further ion manipulations or reaction experiments. The general ion optics design and technical requirements of SRing subsystems are presented and discussed in this paper.

Evaluation of transverse impedances and collective instabilities is important for determining whether a transverse feedback system or damping schemes should be prepared in the BRing (Booster Ring) at the HIAF (High Intensity Heavy-ion Accelerator Facility). In this paper, some dominant transverse impedances are estimated to build a transverse impedance model of the BRing. With this model, all potential transverse instabilities and their growth times or rates are analyzed by analytical methods or simulations, and the results agree with each other. The growth times of some instabilities are shorter than the duration times of corresponding manipulations, which shows transverse instabilities may have many detrimental impacts on the BRing. To cure the transverse instabilities, a transverse feedback system will be proposed in the design of the BRing. Besides, this paper not only shows the transverse instabilities in the BRing, but also provides the whole method for estimating them in the design of a new accelerator facility.

The Isochronous Mass Spectrometry (IMS) based on storage rings is a powerful technique for mass measurement of short-lived exotic nuclei. The transition energy γt of the storage ring is a vital parameter of the IMS technique. It is difficult to measure the γt and its relation to momentum spread or circulating length, especially to monitor the variation of γt during experiments. An experimental investigation on the γt has been performed for the IMS experiment at the Cooler Storage Ring of the Heavy Ion Research Facility in Lanzhou (HIRFL-CSRe). With the velocity measured by two time-of-flight (TOF) detectors, the γt as a function of orbital length can be determined. The influences of higher order magnetic field components on the γt function were inferred for isochronous correction. This paper introduces and investigates the influence of dipole magnetic fields, quadrupole magnetic fields and sextupole magnetic fields on the γt function. With the quadrupole magnets and sextupole magnets corrections, a mass resolution of 171332 (FWHM) and σ(T)∕T=1.34×10−6 were reached, which shall be compared with 31319 (FWHM) and σ(T)∕T=7.35×10−6 obtained without correction.

HIAF-BRing, a new multipurpose accelerator facility of the High Intensity heavy-ion Accelerator Facility project, requires an extremely high vacuum lower than 10−11mbar to fulfill the requirements of radioactive beam physics and high energy density physics. To achieve the required process pressure, the bench-marked codes of VAKTRAK and Molflow+ are used to simulate the pressure profiles of the BRing system. In order to ensure the accuracy of the implementation of VAKTRAK, the computational results are verified by measured pressure data and compared with a new simulation code BOLIDE on the current synchrotron CSRm. Since the verification of VAKTRAK has been done, the pressure profiles of the BRing are calculated with different parameters such as conductance, out-gassing rates and pumping speeds. According to the computational results, the optimal parameters are selected to achieve the required pressure for the BRing.

To evaluate the clinical efficacy and safety with ureteroscopic lithotripsy for the treatment of urinary calculi in infants and young children.

Experience with retroperitoneal laparoscopic dismembered pyeloplasty for the correction of ureteropelvic junction obstruction is extremely limited in infants. We review our experience with this technique in both children and infants to evaluate its role in the latter group.

Substitutions on the P(1) cyclobutyl side chain of SCH 503034 were studied by introduction of hydroxyl and fluoro substituents. Additionally, effects of fluoro substitution on other P1 moieties were evaluated.