Heavy Ion Research Facility Research Articles

Study of neutron dose equivalent at the HIRFL deep tumor therapy terminal

The secondary neutron fields at the deep tumor therapy terminal at HIRFL (Heavy Ion Research Facility in Lanzhou) were investigated. The distributions of neutron ambient dose equivalent were measured with a FHT762 Wendi-II neutron ambient dose equivalent meter as 12C ions with energies of 165, 207, 270, and 350 MeV/u were bombarded on thick tissue-like targets. The thickness of targets used in the experiments was larger than the range of the carbon ions. The neutron spectra and dose equivalent were simulated by using FLUKA code, and the results agree well with the experimental data. The experiment results showed that the neutron dose produced by fragmentation reactions in tissue can be neglected in carbon-ion therapy, even considering their enhanced biological effectiveness. These results are also valuable for radiation protection, especially in the shielding design of high energy heavy ion medical machines.

Dielectronic recombination experiments at the storage rings: From the present CSR to the future HIAF

Dielectronic recombination (DR) experiments of highly charged ions at the storage rings have been developed as a precision spectroscopic tool to investigate the atomic structure as well as nuclear properties of stable and unstable nuclei. The DR experiment on lithium-like argon ions was successfully performed at main Cooler Storage Ring (CSRm) at Heavy Ion Research Facility in Lanzhou (HIRFL) accelerator complex. The DR experiments on heavy highly charged ions and even radioactive ions are currently under preparation at the experimental Cooler Storage Ring (CSRe) at HIRFL. The current status of DR experiments at the CSRm and the preparation of the DR experiments at the CSRe are presented. In addition, an overview of DR experiments by employing an electron cooler and a separated ultra-cold electron target at the upcoming High Intensity heavy ion Accelerator Facility (HIAF) will be given.

Application of SEU imaging for analysis of device architecture using a 25 MeV/u 86Kr ion microbeam at HIRFL

The heavy-ion imaging of single event upset (SEU) in a flash-based field programmable gate array (FPGA) device was carried out for the first time at Heavy Ion Research Facility in Lanzhou (HIRFL). The three shift register chains with separated input and output configurations in device under test (DUT) were used to identify the corresponding logical area rapidly once an upset occurred. The logic units in DUT were partly configured in order to distinguish the registers in SEU images. Based on the above settings, the partial architecture of shift register chains in DUT was imaged by employing the microbeam of 86Kr ion with energy of 25MeV/u in air. The results showed that the physical distribution of registers in DUT had a high consistency with its logical arrangement by comparing SEU image with logic configuration in scanned area.

Hardening of reduced activation ferritic/martensitic steels under the irradiation of high-energy heavy-ion

In order to study the irradiation responses of reduced activation ferritic/martensitic (RAFM) steels which are candidates for fusion reactors, a reduced activation steel is irradiated at a terminal of HIRFL (heavy ion research facility in Lanzhou) with 63 MeV 14N ions and 336 MeV 56Fe ions at -50 ℃. The energies of the incident N/Fe ions are varied from 0.22 MeV/u to 6.17 MeV/u by using an energy degrader at the terminal, so that a plateau region of an atomic displacement damage (0.05-0.2 dpa) is obtained from the near surface to a depth of 24 μm in the specimens. Nanoindentation technique is used to investigate the nano-hardness changes of the samples before and after irradiation. The constant stiffness measurement is used to obtain the depth profile of hardness. The Nix-Gao model taking account of the indentation size effect (ISE) is used to fit the measured hardness and thus a hardness value excluding ISE is obtained. Consequently, the soft substrate effect for lower energy ion irradiation is effectively avoided. It is observed that there seems to be a power function relationship between the hardness and damage for the RAFM steel. The hardness initially increases significantly with the increase of irradiation damage, then increases slowly when the damage reaches to about 0.2 dpa. Positron annihilation is performed to investigate the defect evolution in the material. The positron annihilation lifetime spectra show that the long-lifetime proportion of the RAFM steel increases significantly after being irradiated. This means vacancy clusters are produced by the irradiation, resulting in the change of mechanics property. Even at low irradiation dose, point defects with high density are generated in the steel specimens, and subsequently aggregate into defect clusters, thereby suppressing the dislocation slip.The defect concentration in the material increases continuously with the increase of irradiation damage, which leads to the obvious irradiation hardening phenomenon. When the damage is higher than 0.1 dpa, the increment of mean lifetime gradually decreases due to the existence of a large number of vacancies and dislocations, and it eventually tends to be saturated, which explains why the irradiation hardening increment rate decreases with the increase of irradiation damage in the material.

K-shell X-ray emission from high energy pulsed C6+ ion beam impacting on Ni target

Accurate measurement of the ionization cross section of the target atom induced by collision between ions and atoms is of great significance for studying the atomic shell process and establishing a suitable theoretical model. The experimental data and the theoretical models mostly concentrate on the cases in the low energy region at present. Only a few experimental data of high energy region are reported due to the limitation of experimental conditions. Which theory is more suitable to describe the ionization cross section of the inner shell of the target atom caused by the high energy heavy ions, is necessarily studied experimentally. The C6+ ions provided by the Heavy Ion Research Facility in Lanzhou Electron Cooling Storage Ring, are used to bombard the Ni target, in which the K-shell X-ray of Ni is measured. The incident energies of C6+ ions are 165, 300, 350 and 430 MeV/u respectively. Through analyzing the intensity ratio of K/K X-ray of Ni, it is found that the influence of incident energy on the intensity ratio of K/K X-ray is not obvious. The intensity ratios of this experiment are greater than the experimental values of incident proton and the calculated values based on the Hartree-Slater theory, which may be caused by the multiple-ionization of the L shell. The production cross sections of Ni K-shell X-ray are calculated by the binary encounter approximation (BEA) model, the plane wave Born approximation (PWBA) model and the energy-loss coulomb-repulsion perturbed-stationary-state relativistic (ECPSSR) theory respectively, which are compared with the experimental results in this paper. It is found that the experimental cross section increases with the increasing incident energy, which is consistent with the trend of BEA model estimation, but the experimental value is obviously lower than the theoretical value. We think that BEA model needs to be modified when describing the ionization process in the high energy region.

Design and Simulation of Novel Gated Integrator for the Heavy ion Beam Monitors System

In this study, the objective is to realize a Gated Integrator (GI) circuit for silicon strip, Si(Li), CdZnTe and CsI detectors etc. With the development of radioactive ion beam physics, heavy-charged particles like carbon ions have been applied to the treatment of deep-seated inoperable tumors in the therapy terminal of the Heavy ion Research Facility in Lanzhou (HIRFL) located at the Institute of Modern Physics (IMP), Chinese Academy of Sciences (CAS). A high resolution current measurement circuit was developed to monitor the beam current at 1pA range. The circuit consisted of a low current high sensitivity I/V converter and gated integrator in an energy spectroscopy. A low offset voltage precision amplifier and new guarding and shielding techniques were used in the I/V converter circuit which allowed to measure low current. This paper will show a MOS switch configuration which is used to prevent leakage current and novel technique to compensate a charge injection in the reset switch.

A beam monitor using silicon pixel sensors for hadron therapy

We report the design and test results of a beam monitor developed for online monitoring in hadron therapy. The beam monitor uses eight silicon pixel sensors, Topmetal-II-, as the anode array. Topmetal-II- is a charge sensor designed in a CMOS 0.35µm technology. Each Topmetal-II- sensor has 72×72pixels and the pixel size is 83×83µm2. In our design, the beam passes through the beam monitor without hitting the electrodes, making the beam monitor especially suitable for monitoring heavy ion beams. This design also reduces radiation damage to the beam monitor itself. The beam monitor is tested with a carbon ion beam at the Heavy Ion Research Facility in Lanzhou (HIRFL). Results indicate that the beam monitor can measure position, incidence angle and intensity of the beam with a position resolution better than 20µm, angular resolution about 0.5° and intensity statistical accuracy better than 2%.

The calibration of elastic scattering angular distribution at low energies on HIRFL-RIBLL

The precise calibration of angular distribution of heavy-ion elastic scattering induced by Radioactive Ion Beams (RIBs) at energies around Coulomb barrier on the Radioactive Ion Beam Line in Lanzhou (RIBLL) at the Heavy-Ion Research Facility in Lanzhou (HIRFL) is presented. The beam profile and the scattering angles on the target are deduced by a measurement with two Multi Wire Proportional Chambers (MWPC), and four sets of detector telescopes (including Double-sided Silicon Strip Detectors (DSSD) placed systematically along the beam line, incorporating with Monte Carlo simulation. The MWPCs were used to determine the beam trajectory before the target, and the energies and the positions of scattered particles on the detectors were measured by the DSSDs. Minor corrections on the beam spot and the detector position are performed by assuming the pure Rutherford scattering at angles which are smaller than the related grazing angle. This method is applied for the elastic scattering of 17F on 89Y target at Elab=59MeV and 50MeV.

Prediction of proton-induced SEE error rates for the VATA160 ASIC

We predict proton single event effect (SEE) error rates for the VATA160 ASIC chip on the Dark Matter Particle Explorer (DAMPE) to evaluate its radiation tolerance. Lacking proton test facilities, we built a Monte Carlo simulation tool named PRESTAGE to calculate the proton SEE cross-sections. PRESTAGE is based on the particle transport toolkit Geant4. It adopts a location-dependent strategy to derive the SEE sensitivity of the device from heavy-ion test data, which have been measured at the HI-13 tandem accelerator of the China Institute of Atomic Energy and the heavy-ion research facility in Lanzhou. The AP-8, SOLPRO, and August 1972 worst-case models are used to predict the average and peak proton fluxes on the DAMPE orbit. Calculation results show that the averaged proton SEE error rate for the VATA160 chip is approximately 2.17 × 10−5/device/day. Worst-case error rates for the Van Allen belts and solar energetic particle events are 1–3 orders of magnitude higher than the averaged error rate.

A Flash-ADC data acquisition system developed for a drift chamber array and a digital filter algorithm for signal processing**Supported by National Basic Research Program of China (973) (2015CB856903 and 2014CB845405), partly by National Science Foundation of China (U1332207 and 11375094), and by Tsinghua University Initiative Scientific Research Program

A Flash-ADC data acquisition (DAQ) system has been developed for the drift chamber array designed for the External-Target-Experiment at the Cooling Storage Ring at the Heavy Ion Research Facility, Lanzhou. The simplified readout electronics system has been developed using the Flash-ADC modules and the whole waveform in the sampling window is obtained, with which the time and energy information can be deduced with an offline processing. A digital filter algorithm has been developed to discriminate the noise and the useful signal. With the digital filtering process, the signal to noise ratio (SNR) is increased and a better time and energy resolution can be obtained.

The trigger system for the external target experiment in the HIRFL cooling storage ring**Supported by the National Natural Science Foundation of China (11079003), the Knowledge Innovation Program of the Chinese Academy of Sciences (KJCX2-YW-N27), and the CAS Center for Excellence in Particle Physics (CCEPP).

A trigger system was designed for the external target experiment in the Cooling Storage Ring (CSR) of the Heavy Ion Research Facility in Lanzhou (HIRFL). Considering that different detectors are scattered over a large area, the trigger system is designed based on a master-slave structure and fiber-based serial data transmission technique. The trigger logic is organized in hierarchies, and flexible reconfiguration of the trigger function is achieved based on command register access or overall field-programmable gate array (FPGA) logic on-line reconfiguration controlled by remote computers. We also conducted tests to confirm the function of the trigger electronics, and the results indicate that this trigger system works well.

<x content-type="symbol">α</x> decay studies of the neutron-deficient uranium isotopes <sup>215<x content-type="symbol">-</x>217</sup>U

The α -decay study is an important tool for obtaining information on the nuclear structure of heavy neutron-deficient nuclei. For the N =126 and 124 isotones with even proton number, an intruder state ( π h 9/2 π f 7/2)8+ based on the attractive interaction of f 7/2 protons and f 5/2 neutrons was observed, which increases the binding energy of this configuration with increasing proton number. Additionally, taking into account the octupole correlations, a large-scale shell model calculations predict that the ( π h 9/2 π f 7/2)8+ state lies close or below the ( π h 9 / 2 2 ) 6+ state in the 216Th and 218U. To extend the systematic of the I π =8+ isomeric state in N =124 isotones and search for the most neutron-deficient uranium isotopes, an experiment for the α -decay studies of 215 - 217U was performed at the gas-filled recoil separator SHANS at the Heavy Ion Research Facility in Lanzhou (HIRFL). Heavy ion induced fusion evaporation reactions of the 180W(40Ar, x n)220 - x U ( x =3 - 5) were used to synthesize these neutron-deficient uranium isotopes. The 40Ar beam was delivered by the sector focusing cyclotron of the HIRFL. The evaporation residues recoiled from the thin target were separated in-flight from the primary beam particles by the gas-filled recoil separator SHANS. After passing through two multi-wire proportional counters, the residues were planted into a focal plane detection system. Based on the energy-position-time correlation measurement, the isotopes 215 - 217U were identified. At a beam energy of 187.2 MeV, two α -decaying states were observed in 216U with E α =8.384(30) MeV, T 1/2=

A new type of accelerator power supply based on voltage-type space vector PWM rectification technology

To solve the problems such as low input power factor, a large number of AC current harmonics and instable DC bus voltage due to the diode or thyristor rectifier used in an accelerator power supply, particularly in the Heavy Ion Research Facility in Lanzhou-Cooler Storage Ring (HIRFL-CSR), we designed and built up a new type of accelerator power supply prototype base on voltage-type space vector PWM (SVPWM) rectification technology. All the control strategies are developed in TMS320C28346, which is a digital signal processor from TI. The experimental results indicate that an accelerator power supply with a SVPWM rectifier can solve the problems above well, and the output performance such as stability, tracking error and ripple current meet the requirements of the design. The achievement of prototype confirms that applying voltage-type SVPWM rectification technology in an accelerator power supply is feasible; and it provides a good reference for design and build of this new type of power supply.

Plant Mutation Breeding with Heavy Ion Irradiation at IMP

<p>The Heavy Ion Research Facility in Lanzhou (HIRFL) is one of the ion-beam acceleration facilities intensively used at IMP, founded as national laboratory and opened for user in world from 1992. Since then, a lot of experiments irradiated by heavy ion beam have been carried out in the HIRFL, including plant mutation breeding. In this review, the biological effects induced by heavy ions and their corresponding mechanisms were reported from the point of view of cytological, morphological and molecular levels. To date, a large number of mutants were isolated using heavy ion irradiation IMP, such as early maturity, flower color and shape, high yield and disease resistant. In conclusion, heavy ion beam irradiation is an efficient mutagen and has significant phenotypic variations in plant. Our research will be further focused on transformation of scientific and technological achievements and mutagenic mechanism of heavy ion beam on high plant at the molecular level in the recent future.</p>

Control strategies used in the control software for the Heavy Ion Research Facility in Lanzhou

Automation control systems are important for the operation of an accelerator. To ensure the reliable, stable and flexible operation of the Heavy Ion Research Facility in Lanzhou (HIRFL), several control systems are developed. The developed control systems are the SECRAL control system, the LECR3 control system, the LAPECR1 control system and the Electro-Static septum control system. The corresponding control software systems are developed using Visual C++. To ensure the accuracy, stability and flexibility of the control systems, some special control strategies are developed in the control software systems. This paper provides a detailed description of the main control strategies used in the control software systems. The main control strategies are composed of a reliable communication mechanism, a correct data/command transmission mechanism, an efficient data storage mechanism and an interlock protection mechanism. To guarantee a reliable communication between the devices for the commercially purchased devices and the built in-house ones, a modified heartbeat method is developed. To provide flexible reconstitution function for the control systems, the command queue and the state machine are combined. The message mechanism and the multiple windows mechanism are also used for the module mechanism. The relevant control systems are introduced as examples of these control strategies. These systems have been running stably for several years.

Beam transport experiment with a new kicker control system on the HIRFL**Supported by National Natural Science Foundation of China (U1232123)

A kicker control system is used for beam extraction and injection between two cooling storage rings (CSRs) at the Heavy Ion Research Facility in Lanzhou (HIRFL). To meet the requirements of special physics experiments, the kicker controller has been upgraded, with a new controller designed based on ARM+DSP+FPGA technology and monolithic circuit architecture, which can achieve a precision time delay of 2.5 ns. In September 2014, the new kicker control system was installed in the kicker field, and the test experiment using the system was completed. In addition, a pre-trigger signal was provided by the controller, which was designed to synchronize the beam diagnostic system and physics experiments. Experimental results indicate that the phenomena of “missed kick” and “inefficient kick” were not observed, and the multichannel trigger signal delay could be adjusted individually for kick power supplies in digitization; thus, the beam transport efficiency was improved compared with that of the original system. The fast extraction and injection experiment was successfully completed based on the new kicker control systems for HIRFL.

Design, fabrication, and beam commissioning of a continuous-wave four-rod rf quadrupole

A new heavy-ion linac within a continuous-wave (CW) 4-rod radio-frequency quadrupole (RFQ) was designed and constructed as the injector for the separated-sector cyclotron (SSC) at the Heavy Ion Research Facility at Lanzhou (HIRFL). In this paper, we present the development of and the beam commissioning results for the 53.667 MHz CW RFQ. In the beam dynamics design, the transverse phase advance at zero current, σ0⊥, is maintained at a relatively high level compared with the longitudinal phase advance (σ0∥) to avoid parametric resonance. A quasi-equipartitioning design strategy was applied to control the emittance growth and beam loss. The installation error of the electrodes was checked using a FARO 3D measurement arm during the manufacturing procedure. This method represents a new approach to measuring the position shifts of electrodes in a laboratory environment and provides information regarding the manufacturing quality. The experimental results of rf measurements exhibited general agreement with the simulation results obtained using CST code. During on-line beam testing of the RFQ, two kinds of ion beams (Ar408+ and O165+) were transported and accelerated to 142.8 keV/u, respectively. These results demonstrate that the SSC-Linac has made a significant progress. And the design scheme and technology experiences developed in this work can be applied to other future CW RFQs.20 MoreReceived 22 May 2015DOI:https://doi.org/10.1103/PhysRevAccelBeams.19.010402This article is available under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Physical SystemsAccelerator applicationsPulsed-power acceleratorsAccelerators & Beams

The Industrialization Experience of Scientific Results of HIRFL: Social Benefits, Regional Balanced Development,Government Support, Local Advantage

Heavy Ion Research Facility in Lanzhou (HIRFL) has attained important scientific goals, at the same time, the rising industrial chains represented by HIMM industry and sweet sorghum industry have formed growth pole and given an impetus to readjust and optimize the industrial structure of western region, to improve the sustainable development of the regional society and economy. Through the field research and interviews,analysis and summary are made regarding to the experience in Lanzhou on the layout and industrialization of scientific results of the large scientific facilities: the development planning and the top-level design should pay attention to bring the comprehensive benefits, especially the economic and social benefits, besides consideration of scientific goals. Because the large scientific facilities have additional aspects of the economic and social benefits,the macro layout should lay stress on the balance of regional development; many difficulties exist in the rusults transformation of the large scientific facilities, which can be the mark of high-end and advanced science and technology, such as high uncertainty, long investment recycle time, great risk and so on. Thus, government should set up the special project to support initial research and development and effectively reduce the risk of research and development in enterprise. The development in the comprehensive benefits of the large scientific facilities should combine the practical factors and make full use of the local advantage.

Predictions for proton and heavy ions induced SEUs in 65 nm SRAMs

We report on irradiation induced single event upset (SEU) by high-energy protons and heavy ions. The experiments were performed at the Paul Scherer Institute, and heavy ions at the SEE irradiating Facility on the HI-13 Tandem Accelerator in China's Institute of Atomic Energy, Beijing and the Heavy Ion Research Facility in Lanzhou in the Institute of Modern Physics, Chinese Academy of Sciences. The results of proton and heavy ions induced (SEU) in 65 nm bulk silicon CMOS SRAMS are discussed and the prediction on several typical orbits are presented.

Systematic study of the K X-ray spectra for hollow krypton and xenon atoms in collision process

The satellite and hypersatellite of K X-rays resulted from additional vacancies in L-shell and M-shell for Kr and Xe atoms have been calculated systematically by using the multiconfiguration-Dirac–Fock (MCDF) method, in which the Breit interaction, QED corrections are also considered. The present calculations for diagram lines are in good agreement with available previous results. It is found that the number of spectator vacancies in L shell varies nearly linearly with the energy shifts of both K X-ray satellites and hypersatellites for Kr and Xe atoms. While an additional M shell hole has nearly no effect on the Kα energy shifts in comparison with the small but evident energy shifts of Kβ lines. The simulated spectra based on our results show a good agreement with the current experimental spectra at Heavy-ion Research Facility (HIRFL) in Lanzhou. The results of this paper will be helpful in further interpretation of various K X-ray spectra and better understanding of the collision processes.