Search

Purpose: High-energy heavy ions generated by accelerators utilized in industrial and medical uses. Ar, C, and He heavy ions have been used in the treatment of cancer. In this research, it was tried to calculate the radioactive elements production in healthy tissues around tumors by heavy ions spallation process in the direct usage of highenergy ions for the treatment of cancerous tumors. Materials and Methods: The radioactive elements production in body tissues irradiated with heavy ions was calculated by Monte Carlo N Particle X-version (MCNPX) code based on the Monte Carlo method. The F8 tally card with FT8 command was utilized to derive the activation and spallation data in the range of Z1 to Z2 atomic numbers. Results: A wide range of radioactive elements was created in healthful tissues in Ne, C, Ar, and He heavy ions therapy. Results show that 10Be,14C, 26Al, 36Cl, 39Ar, 40K, 39Ar, 32Si, 22Na, and 36Cl radioactive materials were produced for high-energy heavy ions spallation in healthy soft tissue. Conclusion: The results of this research show that due to using directly high-energy ions to treat internal tumors, healthy soft tissue is activated. Also, by irradiated Ne, C, Ar, and He ions, the radioactive elements are produced with high gains and long half-lives. Therefore, in the therapy of cancerous tumors with high-energy ions, due to the production of radioactive agents, healthy tissues are at high risk. [ABSTRACT FROM AUTHOR]

GaN HEMT devices are sensitive to the single event effect (SEE) caused by heavy ions, and their reliability affects the safe use of space equipment. In this work, a Ge ion (LET = 37 MeV·cm2/mg) and Bi ion (LET = 98 MeV·cm2/mg) were used to irradiate Cascode GaN power devices by heavy ion accelerator experimental device. The differences of SEE under three conditions: pre-applied electrical stress, different LET values, and gate voltages are studied, and the related damage mechanism is discussed. The experimental results show that the pre-application of electrical stress before radiation leads to an electron de-trapping effect, generating defects within the GaN device. These defects will assist in charge collection so that the drain leakage current of the device will be enhanced. The higher the LET value, the more electron–hole pairs are ionized. Therefore, the charge collected by the drain increases, and the burn-out voltage advances. In the off state, the more negative the gate voltage, the higher the drain voltage of the GaN HEMT device, and the more serious the back-channel effect. This study provides an important theoretical basis for the reliability of GaN power devices in radiation environments. [ABSTRACT FROM AUTHOR]

Non-destructive measurements of low-intensity charged particle beams are particularly challenging for beam diagnostics. At the Heavy Ion Accelerator Facility in Lanzhou (HIRFL), beams with weak currents below 1 µA are often provided for experiments. The detection of such low beam current is below the threshold of typical standard beam current transformers. Therefore, a low-intensity monitoring system is developed by using a sensitive capacitive pick-up (PU) and low-noise electronics. This device measures beam currents by digitally analyzing the amplitude of the PU signals using a homodyne detection scheme. During lab tests, the amplitude nonlinearity is <0.5% in the operational range of 1 nA–45 µA and the amplitude resolution is 0.94 nA. At present, four measurement systems for low beam currents are installed at HIRFL for the monitoring of standard operating conditions with low beam currents below 1 µA. After an absolute calibration with a Faraday cup, it can be used for accurate beam intensity measurement with a current resolution of about 1 nA. [ABSTRACT FROM AUTHOR]

The chopper control system which is synchronized by the White Rabbit timing network is designed and implemented to meet the requirements of the chopper of ion source for the High-Intensity Heavy Ion Accelerator Facility (HIAF). The hardware system consists of timing modulation controller, waveform acquisition, parameter setting, and remote control of the chopper power supply. The software includes low-level drivers and top-level applications which are based on Experimental Physics and Industrial Control System (EPICS). The combination of hardware and software completes the interaction of timing messages with the White Rabbit network, waveform acquisition, the setting of timing modulation parameters in several running modes, and remote control of the chopper power supply, etc. The test results show that the system can achieve timing modulation with a resolution of 8 ns and waveform acquisition of embedded EPICS IOC (input/output controller) at a 125 MHz sample rate. The design, implementation, and test of the chopper control system are described in this paper. [ABSTRACT FROM AUTHOR]

In recent years, heavy ion accelerator technology has been rapidly developing worldwide and widely applied in the fields of space radiation simulation and particle therapy. Usually, a very high uniformity in the irradiation area is required for the extracted ion beams, which is crucial because it directly affects the experimental precision and therapeutic effect. Specifically, ultra-large-area and high-uniformity scanning are crucial requirements for spacecraft radiation effects assessment and serve as core specification for beamline terminal design. In the 300 MeV proton and heavy ion accelerator complex at the Space Environment Simulation and Research Infrastructure (SESRI), proton and heavy ion beams will be accelerated and ultimately delivered to three irradiation terminals. In order to achieve the required large irradiation area of 320 mm×320 mm, horizontal and vertical scanning magnets are used in the extraction beam line. However, considering the various requirements for beam species and energies, the tracking accuracy of power supplies (PSs), the eddy current effect of scanning magnets, and the fluctuation of ion bunch structure will reduce the irradiation uniformity. To mitigate these effects, a beam uniformity optimization method based on the measured beam distribution was proposed and applied in the accelerator complex at SESRI. In the experiment, the uniformity is successfully optimized from 75% to over 90% after five iterations of adjustment to the PS waveforms. In this paper, the method and experimental results were introduced. [ABSTRACT FROM AUTHOR]

Background: Using the pencil beam raster scanning method employed at most carbon beam treatment facilities, spots can be moved without interrupting the beam, allowing for the delivery of a dose between spots (move dose). This technique is also known as Dose‐Driven‐Continuous‐Scanning (DDCS). To minimize its impact on HIMAK patient dosimetry, there's an upper limit to the move dose. Spots within a layer are grouped into sets, or "break points," allowing continuous irradiation. The beam is turned off when transitioning between sets or at the end of a treatment layer or spill. The control system beam‐off is accomplished by turning off the RF Knockout (RFKO) extraction and after a brief delay the High Speed Steering Magnet (HSST) redirects the beam transport away from isocenter to a beam dump. Purpose: The influence of the move dose and beam on/off control on the dose distribution and irradiation time was evaluated by measurements never before reported and modelled for Hitachi Carbon DDCS. Method: We conducted fixed‐point and scanning irradiation experiments at three different energies, both with and without breakpoints. For fixed‐point irradiation, we utilized a 2D array detector and an oscilloscope to measure beam intensity over time. The oscilloscope data enabled us to confirm beam‐off and beam‐on timing due to breakpoints, as well as the relative timing of the RFKO signal, HSST signal, and dose monitor (DM) signals. From these measurements, we analyzed and modelled the temporal characteristics of the beam intensity. We also developed a model for the spot shape and amplitude at isocenter occurring after the beam‐off signal which we called flap dose and its dependence on beam intensity. In the case of scanning irradiation, we measured move doses using the 2D array detector and compared these measurements with our model. Result: We observed that the most dominant time variation of the beam intensity was at 1 kHz and its harmonic frequencies. Our findings revealed that the derived beam intensity cannot reach the preset beam intensity when each spot belongs to different breakpoints. The beam‐off time due to breakpoints was approximately 100 ms, while the beam rise time and fall time (tdecay) were remarkably fast, about 10 ms and 0.2 ms, respectively. Moreover, we measured the time lag (tdelay) of approximately 0.2 ms between the RFKO and HSST signals. Since tdelay ≈ tdecay at HIMAK then the HSST is activated after the residual beam intensity, resulting in essentially zero flap dose at isocenter from the HSST. Our measurements of the move dose demonstrated excellent agreement with the modelled move dose. Conclusion: We conducted the first move dose measurement for a Hitachi Carbon synchrotron, and our findings, considering beam on/off control details, indicate that Hitachi's carbon synchrotron provides a stable beam at HIMAK. Our work suggests that measuring both move dose and flap dose should be part of the commissioning process and possibly using our model in the Treatment Planning System (TPS) for new facilities with treatment delivery control systems with higher beam intensities and faster beam‐off control. [ABSTRACT FROM AUTHOR]

Direct electron injection, such as through electron-emitting filaments, is usually difficult to neutralize ion beams to a very high degree. In this paper, the possibility of a pulsed ion beam achieving very high neutralization through the continuous accumulation of cold electrons is investigated using a two-dimensional particle-in-cell code. Three schemes of electron injection, namely, single-point injection, periodic point-source injection, and periodic line-source injection, are numerically studied and compared. The simulations show that even if an excess of electrons are injected, the single-point electron source is difficult to neutralize the ion beam pulse to exceed 90%, consistent with existing experiments. It is found that the spontaneous cooling mechanism of neutralizing electrons is able to improve the neutralization of the ion beam to a certain extent, but it requires a lot of time. By using a smaller injection current, the latter two injection schemes not only effectively suppress solitary waves, but more importantly, they continuously provide cold electrons that can accumulate inside the ion beam, thereby significantly improving the neutralization of the ion beam in a short period of time. The results show that periodic line-emission sources can neutralize the ion beam to over 99%, but periodic point-emission sources exhibit relatively poor neutralization performance due to their higher virtual-cathode potential. The research results can provide a reference for the design of neutralizing sources in applications that pursue very high neutralization of ion beam pulses, such as heavy ion fusion accelerators. [ABSTRACT FROM AUTHOR]

This article investigates the radiolysis of a mixture of nitric acid with water (HNO3:H2O) at 16 K in high-vacuum (residual pressure < 10−6 mbar). A nitric acid-water ice film was exposed to 40 MeV 58Ni11+ ion beam in a heavy ion accelerator facility in France. For this astrochemically- and atmospherically-relevant ice mixture of nitric acid and water, we analyze the possible formation and destruction processes of N–O bearing species, thus providing spectroscopic data in the infrared (IR) region for theoretical, laboratory and observational future studies. The irradiation synthetized 18 species which were posteriorly examined by infrared spectroscopy: N2O, NH3, NO, NO2 and H x N y O z molecules, such as hidroxylamine (NH2OH), nitrous acid (HONO) as well as other species with bonding N–O, N–H and H–O–N converting surface-adsorbed nitrogen oxides into astrochemically active NO x. The interaction of HNO3 and H2O originates H–N–O molecular complexes, which were investigated as particular cases of the hydrogen-bonded species formed by a more electronegative atom (N or O) interacts intra or intermolecularly with a donor atom (N or O) and observed in the interstellar medium with higher quantities or great abundances. The HNO3 and H2O destruction cross sections have been determined to be 8.5 × 10−13 and 1.2 × 10−13 cm2, respectively, for the mentioned experimental conditions. [ABSTRACT FROM AUTHOR]

Dipole magnet vacuum chambers are among the most critical and costly components of rapid-cycling accelerator facilities. Alternative approaches to traditional ceramic chambers have been explored for the implementation of fast-ramping dipole-magnet vacuum chambers, including thin-wall metallic beam pipe chambers strengthened with transverse ribs and ceramic rings inside thin-walled chambers. Here, we report a novel 3D-printed titanium alloy cage inside the thin-wall vacuum chamber, which is designed for high-intensity heavy ion accelerator facility (HIAF) to reduce manufacturing difficulty and cost, shorten the production cycle, and improve the quality. Comprehensive studies were undertaken to characterize the impedance of the 3D-printed titanium alloy cage inside the thin-wall vacuum chamber. The beam-coupling impedance and eddy currents of the new thin-wall vacuum chamber were studied mostly numerically. Strategies for further reducing the beam-coupling impedance were explored. In addition, impedance bench measurements using the "half wavelength" resonant method were conducted to identify the longitudinal and transverse impedances of the 3D-printed titanium alloy cage inside the thin-wall vacuum chamber prototype experimentally. The simulated and measured results for the impedance were consistent. Furthermore, a campaign for resonance-check measurements on the 3D-printed titanium alloy ring loaded inside a thin-wall vacuum chamber prototype was launched. This novel thin-wall vacuum chamber structure is now entering the fabrication stage and will soon be ready for installation in the Booster Ring (BRing). [ABSTRACT FROM AUTHOR]

Experiments at the NASA Space Radiation Laboratory were performed to develop a benchmark dataset relevant to space radiation shielding scenarios by bombarding aluminum and polyethylene targets with galactic cosmic ray-like ion beams. Unique to this experiment, a dual-target configuration was used to emulate an enclosed environment in space in which the radiation environment must be characterized. Neutrons produced by interactions in both thick targets were detected and characterized; this paper discusses the neutrons produced in the most upstream of the two thick targets, detailing the role of source ion and target configuration on neutron yield. [ABSTRACT FROM AUTHOR]

RAON (Rare Isotope Accelerator complex for ON-line experiments) heavy ion accelerator facility in Korea is preparing for producing rare isotopes using Isotope Separation On-line (ISOL) facility. Rare isotopes will be produced by a 70 MeV proton beam incident on the target system. Expecting the harsh radiation environment of the target area, the module system has been adopted. The module system in the ISOL facility consists of target ion source (TIS), rare isotope (RI) transport, and proton beam diagnostic modules. In order to handle and maintain the module system, the remote handling (RH) systems are developed and tested. [ABSTRACT FROM AUTHOR]

The NICA (Nuclotron-based Ion Collider fAcility) project at the Joint Institute for Nuclear Research (JINR, Dubna, Russia) is aimed at the construction of a new accelerator complex for heavy ions and polarized particles. Heavy-ion collisions at NICA are planned to be studied in the region of the highest net-baryon density, which favors the formation of bound nuclear systems with strangeness hypernuclei. The multipurpose detector (MPD) at NICA is designed to reconstruct interactions of relativistic nuclei in a high-multiplicity environment. In this paper, we report the feasibility study results for the reconstruction of Λ 3 H, Λ 4 H and Λ 4 He in Bi+Bi collisions at the nucleon-nucleon center-of-mass energy, s N N = 9.2 GeV. [ABSTRACT FROM AUTHOR]

Mutation breeding through irradiation has been applied to several varieties and genetic resources since the discovery of the use of X-rays for inducing mutations in plants by Stadler in 1928. A heavy ion beam with high linear energy transfer (LET) shows a higher relative biological effectiveness (RBE), and it is more effective in inducing plant mutations than low LET radiations, such as X-rays, gamma rays, and electrons. Since early 1990s, several plant breeding programs in Japan have used heavy ion beams from accelerators. These beams impart a high energy effect on a local target; therefore, they induce a higher number of single and double strand DNA breaks. In addition, they induce a large number of DNA deletions than low LET radiations. Therefore, a heavy ion beam is superior to low LET radiations in terms of induction rate and the mutation spectrum. In Korea, a heavy ion accelerator that can be used for breeding is under construction. However, a large-capacity proton accelerator (KOMAC: Korea Multi-purpose Accelerator Complex) was built recently, and it is a pioneer step in breeding research worldwide. This review summarizes the basic characteristics, successful research achievements, and the prospect of application of high LET accelerator beams in plant mutation breeding. [ABSTRACT FROM AUTHOR]

A simple analytical formulas for estimation of the yield and angular distribution of neutrons from thick targets would be useful for calculating the biological protection of heavy ion accelerators with energy (1–6) MeV/nucleon. The results of the calculation with this formulas were compared with those obtained using the LISE++ and FLUKA programs as well as with the available experimental data. As a result, it can be stated that the proposed calculation method can be used for quick assessment. The deviation of the results of such calculations from more accurate ones does not exceed a factor of two, which is comparable with the deviations in the calculation of biological shielding due to a variety in the protection properties of the materials used or in their thickness. [Display omitted] [ABSTRACT FROM AUTHOR]

Vacuum arc ion sources are capable of generating pulsed ion beams of any solid-state conducting material and are used as injectors in heavy ion accelerators and technological implanters for surface modification of different materials. Without any special measures to increase the charge states of ions with typical arc discharge parameters, at an arc current amplitude of several hundred amperes and a pulse duration of several tens of microseconds, the charge states of ions in the beam do not exceed 5+, and the average ion charge is in the range from 1+ to 3+, depending on the cathode material. An increase in the charge states of vacuum arc plasma ions makes it possible to increase the ion energy in the extracted beam without a corresponding increase in the accelerating voltage or to form ions with a given energy at a significantly lower accelerating voltage. The charge states can be increased by increasing the amplitude of the discharge current and reducing its pulse duration. This article presents a study of the processes of generating beams of multiply charged heavy metal ions using bismuth ions as an example in a high-current vacuum arc with a kiloampere current amplitude at a submicrosecond pulse duration. By shortening the duration of the arc current pulse, the most probable charge state of ions in the extracted 18+ beam is formed, which is a record for bismuth. [ABSTRACT FROM AUTHOR]

The Low Energy Heavy Ion Accelerator Facility (LEAF) is a low-energy, high-intensity heavy-ion linear accelerator facility at Institute of Modern Physics (IMP) for multidiscipline research. The beam bunch repetition rate coincides with the LINAC frequency of 81.25 MHz, resulting in a 12.3 ns period. However, in the context of certain nuclear physics experiments, a longer bunch spacing is deemed essential for the precise detection of experimental products. To address this need, a strategy to extend the bunch spacing to 98 ns has been proposed by integrating a pre-buncher operating at a fundamental frequency of 10.156 MHz before the radio-frequency quadrupole (RFQ) in conjunction with a fast chopper in the medium energy beam transport (MEBT) system. The pre-buncher is a pivotal component in enabling a greater beam current at the target, surpassing the capability of employing a chopper alone. To enhance the bunching efficiency, the pre-buncher operates with two frequencies: the fundamental frequency of 10.156 MHz and its first sub-harmonic of 20.3125 MHz, each of which is produced by a coaxial resonator. This paper describes the design, manufacture, off-line testing, and beam commissioning of the pre-buncher. [ABSTRACT FROM AUTHOR]

Ion accelerator is а multi-tool used for effects of neutron irradiation of reactor materials simulating. The heavy ion accelerator HIPr (heavy ion prototype) is used for radiation damage in steels and alloys simulating at ITEP (NRC "Kurchatov institute"). The main irradiations is carried out with iron ions Fe2+ but, if necessary, vanadium, tantalum, carbon and many others ions beams can be used. It is necessary to implant hydrogen and helium into the area of damage for effect of nuclear reaction products on reactor structural materials simulating. The second channel is created for simultaneous irradiation with heavy and light ions for improving experiments. The paper considers solenoid design. The solenoid is used to a helium ion beam from ECR source focusing and the method of its power supply. [ABSTRACT FROM AUTHOR]

The HEBT channel is designed for transportation of 4 MeV/u energy ion beams with Z/A = 1/4–1/8 from linac to stripping target to prepare the beam for injection into the booster. The channel consists of magnetic quadrupole lenses providing transverse focusing of the beam and the debuncher to reduce the particles momentum spread to ±0.3%. Beam dynamic simulation was carried out taking into account three-dimensional distributions of the quadrupole lenses magnetic fields and electric fields of the debuncher. [ABSTRACT FROM AUTHOR]

The resource of nuclear facilities is largely limited by the degradation of structural or functional materials. Under the action of high-energy neutrons, defects in the crystal lattice appear in the material and the accumulation of transmutation products (helium and hydrogen) occurs in the structure of the material. Qualification of structural materials using reactor irradiation takes several years, and the samples of materials themselves become activated, which makes subsequent post-reactor tests difficult. Simulation experiments on a beam of heavy ions making it possible to analyze the radiation resistance of structural materials of nuclear and fusion reactors have been carried out at the Kurchatov Complex of Theoretical and Experimental Physics (National Research Center Kurchatov Institute) since 2009. Simulation experiments at an accelerator make it possible to carry out high-dose tests in no more than a few days with control over the conditions of the irradiation (temperature of target samples, ion flux, radiation dose). The paper presents a description of the simulation irradiations carried out at the HIPr heavy ion accelerator. [ABSTRACT FROM AUTHOR]

Particle counting analysis is a possible way to characterize GeV-scale, multi-species ions produced in laser-driven experiments. We present a multi-layered scintillation detector to differentiate multi-species ions of different masses and energies. The proposed detector concept offers potential advantages over conventional diagnostics in terms of (1) high sensitivity to GeV ions, (2) realtime analysis, and (3) the ability to differentiate ions with the same charge-to-mass ratio. A novel choice of multiple scintillators with different ion stopping powers results in a significant difference in energy deposition between the scintillators, allowing accurate particle identification in the GeV range. Here, we report a successful demonstration of particle identification for heavy ions, performed at the Heavy Ion Medical Accelerator in Chiba. In the experiment, the proposed detector setup showed the ability to differentiate particles with similar atomic numbers, such as C6+ and O8+ ions, and provided an excellent energy resolution of 0.41%–1.2% (including relativistic effect, 0.51%--1.6%). [ABSTRACT FROM AUTHOR]

Zirconium-93 is a long-lived radionuclide with a half-life of (1.61 ± 0.05) × 106 yr. Production cross sections for 93Zr by neutron capture on stable 92Zr in the keV and thermal energy ranges are important input parameters for astrophysical network calculations and nuclear industry, respectively. Despite their importance, existing experimental data suffer from large uncertainties. Here, the combination of neutron activation and accelerator mass spectrometry (AMS) is presented as an alternative method to online time-of-flight measurements for the determination of these cross sections. The main challenges for AMS of 93Zr are the interference from the stable isobar 93Nb and the production of suitable reference material. At the Heavy Ion Accelerator Facility (HIAF) the first challenge is tackled with the available high particle energies and by investigating different Zr compounds and extracted molecular beams. Using ZrF 5 − beams extracted from ZrF 4 sample material, it is shown that the Nb background can be reduced by up to two orders of magnitude relative to the extraction of ZrO− beams from ZrO 2. Using the 13+ charge state and particle energies of ∼190 MeV, 93Zr/Zr background levels in the 10−12 range are regularly achieved at HIAF. The ZrF 5 − output from ZrF 4 samples may be highly variable but can be stabilised using an intimate mixture of ZrF 4 and PbF 2 at a ratio of 1:10 that has been dried down from a concentrated hydrofluoric acid solution. An option to produce a well-characterised 93Zr reference material by utilising the well-known 235U-fission yield of 93Zr is discussed. Once this remaining challenge is resolved, accurate measurements of the astrophysically and technologically relevant neutron-capture cross sections of 92Zr using AMS will be possible at HIAF. [ABSTRACT FROM AUTHOR]

In the magnetic field measurement of accelerator magnets, efficient and accurate positioning of the magnetic field measurement system and the magnet is a critical process. By analyzing the mechanical structure and working principle of harmonic coil magnetic field measurement system, an automatic positioning technology is proposed in this research for the high-precision and fast positioning of multipole magnet and harmonic coil magnetic field measurement system. Through the special design and comprehensive application of multi-camera photogrammetry system, control system and six-degree-of-freedom (6DoF) attitude automatic adjustment system, fast non-contact measurement and automatic attitude adjustment of harmonic coil magnetic field measurement system and multipole magnet can be realized. The proposed automatic positioning system and operation scheme can not only save labor costs, but also improve the reliability of harmonic coils and the positioning efficiency of magnetic field measurement system. The proposed research can also monitor the position changes of the harmonic coil and the multipole magnet in the magnetic field measurement process in real time through the multi-camera photogrammetry system, and further control the accuracy of the magnetic field measurement of the harmonic coil. [ABSTRACT FROM AUTHOR]

Objective. In carbon ion therapy, the visualization of the range of incident particles in a patient body is important for treatment verification. In-beam positron emission tomography (PET) imaging is one of the methods to verify the treatment in ion therapy due to the high quality of PET images. We have shown the feasibility of in-beam PET imaging of radioactive 15O and 11C ion beams for range verification using our OpenPET system. Recently, we developed a whole gamma imager (WGI) that can simultaneously work as PET, single gamma ray and triple gamma ray imaging. The WGI has high potential to detect the location of 10C, which emits positrons with a simultaneous gamma ray of 718 keV, within the patient’s body during ion therapy. Approach. In this work, we focus on investigating the performance of WGI for 10C imaging and its feasibility for range verification in carbon ion therapy. First, the performance of the WGI was studied to image a 10C point source using the Geant4 toolkit. Then, the feasibility of WGI was investigated for an irradiated polymethyl methacrylate (PMMA) phantom with a 10C ion beam at the carbon therapy facility of the Heavy Ion Medical Accelerator in Chiba. Main results. The average spatial resolution and sensitivity for the simulated 10C point source at the centre of the field of view were 5.5 mm FWHM and 0.010%, respectively. The depth dose of the 10C ion beam was measured, and the triple gamma image of 10C nuclides for an irradiated PMMA phantom was obtained by applying a simple back projection to the detected triple gammas. Significance. The shift between Bragg peak position and position of the peak of the triple gamma image in an irradiated PMMA phantom was 2.8 ± 0.8 mm, which demonstrates the capability of triple gamma imaging using WGI for range verification of 10C ion beams. [ABSTRACT FROM AUTHOR]

The current topology schemes of heavy ion accelerator power supply have serious pollution to the power grid caused by low power factor of the grid side. Considering the characteristics of adjustable power factor and bidirectional energy transfer of the matrix converter, the possibility of which applied to the accelerator DC power supply is studied and three kinds of backup topology schemes including the preceding regulated matrix rectifier (MR) are proposed in this article. Given the actual situation of accelerator power supply, research has been focused on the modulation strategy suitable for the topology of the preceding regulated MR and simulation validation. Based on simulation of the preceding regulated MR scheme, a matrix power prototype is developed. A power factor tester is utilized to test grid side power factor. According to the experimental results, it is prospectively feasible to apply the preceding regulated MR topology to accelerator DC power supply, with excellent performance of the grid side. [ABSTRACT FROM AUTHOR]

Objective. A retrospective study on secondary cancer risk on carbon ion radiotherapy (CIRT) is ongoing at the Heavy Ion Medical Accelerator in Chiba (HIMAC). The reconstruction of the whole-body patient dose distribution is the key issue in the study because dose distribution only around the planning target volume was evaluated in the treatment planning system. Approach. We therefore developed a new dose reconstruction system based on the Particle and Heavy Ion Transport code System (PHITS) coupled with the treatment plan DICOM data set by extending the functionalities of RadioTherapy package based on PHITS (RT-PHITS). In the system, the geometry of patient-specific beam devices such as the range shifter, range compensator, and collimators as well as the individual patient’s body are automatically reconstructed. Various functions useful for retrospective analysis on the CIRT are implemented in the system, such as those for separately deducing dose contributions from different secondary particles and their origins. Main results. The accuracy of the developed system was validated by comparing the dose distribution to the experimental data measured in a water tank and using a treatment plan on an anthropomorphic phantom. Significance. The extended RT-PHITS will be used in epidemiological studies based on clinical data from HIMAC. [ABSTRACT FROM AUTHOR]

In the future, a new superconducting (SC) continuous wave (CW) high intensity heavy ion HElmholtz LInear ACcelerator (HELIAC) should provide ion beams with maximum beam energy above the Coulomb barrier for the Super Heavy Element program at GSI (Gesellschaft für Schwerionenforschung, in Engl.: Association for Heavy Ion Research). The HELIAC consists of a SC main accelerator supplied by a normal conducting injector, which comprises an electron cyclotron resonance ion source, a radio-frequency quadrupole, and two separate interdigital H-mode drift-tube linear accelerator cavities, based on an Alternating Phase Focusing (APF) scheme. Together, both cavities will accelerate ions from 300 to 1400 keV/u with only one external quadrupole triplet for transverse focusing in between. Due to the demanding requirements of the APF concept on the voltage distribution along the beam axis on the one hand and the CW operation on the other hand, the optimization of each cavity concerning RF, mechanical, and thermal properties is crucial for the successful operation of the HELIAC injector. [ABSTRACT FROM AUTHOR]

A new digital beam position and phase measurement (BPM) system was designed for the ion-Linac accelerator at the high intensity heavy ion accelerator facility. The fundamental and second harmonic signals are retrieved from the BPM electrodes to simultaneously calculate their respective beam positions and phases. All data acquisition and digital signal processing algorithm routines are performed in a field programmable gate array (FPGA). The position and phase information are obtained by using the in-phase and quadrature demodulation method. A practical and straightforward method is used to generate the second harmonic reference signal for processing the second harmonic beam signal. The reconfigurable filters are integrated into the FPGA to allow the measurement of short beam pulse length. The laboratory test results show that the achieved phase resolution is better than 0.2° and 0.03° when the input signal is −60 and −45 dBm, respectively. A position resolution better than 30 μm was achieved for an input power level of approximately −60 dBm, and it can reach 7 μm with the input power higher than −45 dBm. The entire execution time of the algorithm is accomplished within 3.4 µs, which provides a sufficient reaction time for the fast beam interlock signal to the machine protection system. The performance of this newly designed prototype BPM electronics was evaluated with the online proton beam. [ABSTRACT FROM AUTHOR]

To measure excitation functions of particle-induced prompt gamma-ray production reactions on Li, a thin LiF target was fabricated by thermal evaporation technique onto self-supporting Ag film. The thickness and the 'stochiometric' ratio of the thin LiF target was measured using Elastic 'Back scattering' Spectroscopy (EBS), Particle Induced Gamma-ray Emission (PIGE), and Nuclear Reaction Analysis (NRA) techniques. The target was characterized to check uniformity and its stability under beam bombardment. Carbon and molybdenium contamination in the target also were examinated. The values of the thickness of the target obtained by EBS, PIGE and NRA techniques are in good agreement with each other, within the estimated uncertainties. Measurements were conducted using the proton/deuteron beams of the 3 MV 'Van de Graaff' electrostatic accelerator of Nuclear Science and Technology Research Institute (NSTRI). All results are presented in an absolute approach by using the experimental cross-section values available through the Ion Beam Nuclear Data Library (IBANDL). [ABSTRACT FROM AUTHOR]

A high-power solid-sate based radio frequency power source is introduced in this paper. Solid-state based amplifiers are much more efficient than microwave tubes and can be used in compact electron cyclotron resonance (ECR) ion sources. A reliable negative bias voltage controller is proposed to drive the power source's main power amplifier, which can deliver up to 300 W power to the ion chamber. The selected high-power transistor is internally matched on the input side but the output side is matched in this paper to deliver maximum power to the load. The bias circuit was fabricated on an FR4 substrate and measurement results were obtained to verify the functionality of the bias sequencer. Analog simulations were done by LTSPICE and high-frequency simulations are performed with the momentum RF simulator of Advanced Design System (ADS). The output power of the proposed structure is tunable with 0.5 dB resolution and can deliver 300 mW to 300 W power to the ion chamber. [ABSTRACT FROM AUTHOR]

In 2008, Michigan State University was selected to establish the Facility for Rare Isotope Beams (FRIB). Construction of the FRIB accelerator was completed in January 2022. Phased accelerator commissioning with heavy ion beams started in 2017 with the normal-conducting ion source and radio-frequency quadrupole. In April 2021, the full FRIB driver linear accelerator (linac) was commissioned, with heavy ion beams accelerated to energies above 200 MeV/nucleon by 324 superconducting radiofrequency (SRF) resonators operating at 2 K and 4 K with liquid-helium cooling. In preparation for high-power operation, a liquid lithium charge stripper was commissioned with heavy ion beams up to uranium-238, followed by the simultaneous acceleration of multiple-charge-state heavy ion beams to energies above 200 MeV/nucleon. In December 2021, selenium-84 was produced with the FRIB target using a krypton-86 primary beam, demonstrating FRIB's capability for scientific discovery. [ABSTRACT FROM AUTHOR]

The 19th International Conference on Electromagnetic Isotope Separators and Related Topics (EMIS XIX) was held at RAON in Daejeon, South Korea from October 3 to 7, 2022. The conference, originally scheduled for 2021, was postponed due to the COVID-19 pandemic. The conference focused on topics such as isotope production, ion source techniques, and applications of radioactive ion beams. RAON, the hosting facility, is a heavy ion accelerator facility that promotes the study of rare isotopes. The conference had 156 registered participants from 15 different countries and included tours of the RAON facility and the Gonsanseong Fortress. The next EMIS conference will be hosted by TRIUMF in Canada in 2024. [Extracted from the article]

The high-intensity heavy ion accelerator facility is a next-generation advanced heavy-ion accelerator facility built by the Institute of Modern Physics, Chinese Academy of Sciences. The RFQ is designed to provide a continuous wave beam and 2 mA pulse beam with high-quality longitudinal beam distribution for the injection linear accelerator. Two different designs of aiming to suppress the longitudinal emittance were studied, and the optimized scheme which composed of a three-harmonic pre-buncher and an RFQ accelerator with small longitudinal acceptance was chosen. More emphasis is put on the section between pre-buncher and RFQ, where the space charge effect becomes severe with bunched beam. The optimal design and the analysis are presented in this paper. [ABSTRACT FROM AUTHOR]

Purpose: Carbon ion radiotherapy for prostate cancer was performed using two fine needle Gold Anchor (GA) markers for patient position verification in Osaka Heavy Ion Medical Accelerator in Kansai (Osaka HIMAK). The present study examined treatment plans for prostate cases using beam‐specific planning target volume (bsPTV) based on the effect of the markers on dose distribution and analysis of target movements. Materials and Methods: Gafchromic EBT3 film was used to measure dose perturbations caused by markers. First, the relationships between the irradiated film density and absolute dose with different linear energy transfer distributions within a spread‐out Bragg peak (SOBP) were confirmed. Then, to derive the effect of markers, two types of markers, including GA, were placed at the proximal, center, and distal depths within the same SOBP, and dose distributions behind the markers were measured using the films. The amount of internal motion of prostate was derived from irradiation results and analyzed to determine the margins of the bsPTV. Results: The linearity of the film densities against absolute doses was constant within the SOBP and the amount of dose perturbations caused by the markers was quantitatively estimated from the film densities. The dose perturbation close behind the markers was smallest (<10% among depths within the SOBP regardless of types of markers) and increased with depth. The effect of two types of GAs on dose distributions was small and could be ignored in the treatment planning. Based on the analysis results of internal motions of prostate, required margins of the bsPTV were found to be 8, 7, and 7 mm in left–right (LR), anterior–posterior (AP), and superior–inferior (SI) directions, respectively. Conclusion: We evaluated the dose reductions caused by markers and determined the margins of the bsPTV, which was applied to the treatment using fiducial markers, using the analysis results of prostate movements. [ABSTRACT FROM AUTHOR]

A new diagnosis method for the discriminative detection of laser-accelerated multi-MeV carbon ions from background oxygen ions utilizing solid-state nuclear track detectors (SSNTDs) is proposed. The idea is to combine two kinds of SSNTDs having different track registration sensitivities: Bisphenol A polycarbonate detects carbon and the heavier ions, and polyethylene terephthalate detects oxygen and the heavier ions. The method is calibrated with mono-energetic carbon and oxygen ion beams from the heavy ion accelerator. Based on the calibration data, the method is applied to identify carbon ions accelerated from multilayered graphene targets irradiated by a high-power laser, where the generation of high-energy high-purity carbon ions is expected. It is found that 93 ± 1% of the accelerated heavy ions with energies larger than 14 MeV are carbons. The results thus obtained support that carbon-rich heavy ion acceleration is achieved. [ABSTRACT FROM AUTHOR]

Radioprotectors with few side effects are useful for carbon-ion therapy, which directly induces clustering damage in DNA. With the aim of finding the most effective radioprotector, we investigated the effects of selected amino acids which might have chemical DNA-repair functions against therapeutic carbon ions. In the current study, we employed five amino acids: tryptophan (Trp), cysteine (Cys), methionine (Met), valine (Val) and alanine (Ala). Samples of supercoiled pBR322 plasmid DNA with a 17 mM amino acid were prepared in TE buffer (10 mM Tris, 1 mM ethylenediaminetetraacetic acid, pH 7.5). Phosphate buffered saline (PBS) was also used in assays of the 0.17 mM amino acid. The samples were irradiated with carbon-ion beams (290 MeV/u) on 6 cm spread-out Bragg peak at the National Institute of Radiological Sciences and Heavy Ion Medical Accelerator in Chiba, Japan. Breaks in the DNA were detected as changes in the plasmids and quantified by subsequent electrophoresis on agarose gels. DNA damage yields and protection factors for each amino acid were calculated as ratios relative to reagent-free controls. Trp and Cys showed radioprotective effects against plasmid DNA damage induced by carbon-ion beam, both in PBS and TE buffer, comparable to those of Met. The double-strand break (DSB) yields and protective effects of Trp were comparable to those of Cys. The yields of both single-strand breaks and DSBs correlated with the scavenging capacity of hydroxyl radicals (rate constant for scavenging hydroxyl radicals multiplied by the amino acid concentration) in bulk solution. These data indicate that the radioprotective effects of amino acids against plasmid DNA damage induced by carbon ions could be explained primarily by the scavenging capacity of hydroxyl radicals. These findings suggest that some amino acids, such as Trp, Cys and Met, have good potential as radioprotectors for preventing DNA damage in normal tissues in carbon-ion therapy. [ABSTRACT FROM AUTHOR]

Metastatic disease to the uterine cervix is exceedingly rare and past report showed incidence as low as 0.3%. Especially, pancreatic cancer metastatic to the uterine cervix is exceptionally rare. We encountered a case of recurrent pancreatic cancer presenting as a solitary metastatic to the uterine cervix. And this case we operated with the surgical method called transvaginal Natural Orifice Transluminal Endoscopic Surgery (vNOTES). A 71 years old women with a history of uterine prolapse cared by ring pessary for 10 years. She treated Stage4 advanced pancreatic adenosquamous cell carcinoma. She had distal pancreatectomy and splenectomy and then cared by TS-1 adjuvant chemotherapy. One year later, she was found to have elevated carcinoembryonic antigen level and para-aortic lymph node mass, and treated by heavy ion medical accelerator. Six months later, she consulted us with vaginal bleeding. We did further examination and found the uterine cervix mass and it showed adenocarcinoma, but we didn't know whether primary or not. So, we decided to do hysterectomy with vNOTES, because vNOTES can observe the abdominal cavity, can adnexectomy and is less invasive than open surgery. She was discharged fourth days after surgery. Pathological examination revealed metastatic pancreatic cancer to the uterine cervix, no malignant cell in ascites. Pancreatic cancer metastatic to the uterine cervix is exceptionally rare. So, to diagnosis, surgical reduction is needed. Therefore, surgery should be as minimally invasive as possible and vNOTES contributed to that. Metastatic disease to the uterine cervix is rare, but important entity for clinicians to consider. And surgical management is important. [ABSTRACT FROM AUTHOR]