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Magnetic topological states of matter provide a fertile playground for emerging topological physics and phenomena. The current main focus is on materials whose magnetism stems from 3d magnetic transition elements, e.g., MnBi2Te4, Fe3Sn2 and Co3Sn2S2. In contrast, topological materials with the magnetism from rare earth elements remain largely unexplored. Here we report rare earth antiferromagnet GdAuAl4Ge2 as a candidate magnetic topological metal. Angle resolved photoemission spectroscopy and first-principles calculations have revealed multiple bulk bands crossing the Fermi level and pairs of low energy surface states. According to the parity and Wannier charge center analyses, these bulk bands possess nontrivial Z2 topology, establishing a strong topological insulator state in the nonmagnetic phase. Furthermore, the surface band pairs exhibit strong termination dependence which provides insight into their origin. Our results suggest GdAuAl4Ge2 as a rare earth platform to explore the interplay between band topology, magnetism and f electron correlation, calling for further study targeting on its magnetic structure, magnetic topology state, transport behavior and microscopic properties.

The simple kagome-lattice band structure possesses Dirac cones, flat band, and saddle point with van Hove singularities in the electronic density of states, facilitating the emergence of various electronic orders. Here we report a titanium-based kagome metal CsTi3Bi5 where titanium atoms form a kagome network, resembling its isostructural compound CsV3Sb5. Thermodynamic properties including the magnetization, resistance, and heat capacity reveal the conventional Fermi liquid behavior in the kagome metal CsTi3Bi5 and no signature of superconducting or charge density wave (CDW) transition anomaly down to 85 mK. Systematic angle-resolved photoemission spectroscopy measurements reveal multiple bands crossing the Fermi level, consistent with the first-principles calculations. The flat band formed by the destructive interference of hopping in the kagome lattice is observed directly. Compared to CsV3Sb5, the van Hove singularities are pushed far away above the Fermi level in CsTi3Bi5, in line with the absence of CDW. Furthermore, the first-principles calculations identify the nontrivial Z2 topological properties for those bands crossing the Fermi level, accompanied by several local band inversions. Our results suppose CsTi3Bi5 as a complementary platform to explore the superconductivity and nontrivial band topology.

Dielectronic recombination (DR) rate coefficients for carbon-like Kr30+ have been measured over the collision energy of 0–60 eV using the heavy-ion storage ring CSRe at the Institute of Modern Physics in Lanzhou, China. The present DR spectrum covers the resonances associated with the 2 s 2 2 p 2 [ 3 P 0 ] → 2 s 2 2 p 2 [ 3 P 1 , 2 ] , 2 s 2 p 3 and 2 p 4 ( Δ n = 0 ) core excitations. The corresponding DR resonance energies and strengths have been calculated by using the flexible atomic code (FAC) to understand the measured results. An overall agreement has been obtained between the experiment and theory, except for the data at the collision energies below 7 eV and in 35–38 eV, where the electronic correlation effect is strong. In particular, the resonances from the trielectronic recombination due to 2 s 2 2 p 2 + e − → 2 p 4 [ 1 D 2 ] 6 l have been identified with the help of the FAC calculation. Temperature-dependent plasma recombination rate coefficients were derived from the measured DR rate coefficients for the temperature range 103–107 K and compared with our FAC calculations as well as the previous AUTOSTRUCTURE calculations by Zatsarinny et al (2004 Astron. Astrophys. 417 1173–81). The FAC and AUTOSTRUCTURE calculations are in good agreement with the presently derived plasma rate coefficients. The present work provides the benchmark data for astrophysical and laboratory plasma modeling.

A proposal for simulating the Dicke-Lattice model in a mechanics-controlled hybrid quantum system is studied here. An array of coupled mechanical resonators (MRs) can homogeneously interact with a group of trapped Bose–Einstein condensates (BECs) via the gradient magnetic field induced by the oscillating resonators. Assisted by the classical dichromatic radio-wave fields, each subsystem with the BEC-MR interaction can mimic the Dicke type spin-phonon interaction, and the whole system is therefore extended to a lattice of Dicke models with the additional adjacent phonon-phonon hopping couplings. In view of this lattice model with the Z 2 symmetry, its quantum phase transitions behavior can be controlled by this periodic phonon-phonon interactions in the momentum space. This investigation may be considered as a fresh attempt on manipulating the critical behaviors of the collective spins through the external mechanical method.

Digital twin is the digital expression of physical entities. With the further development of big data and artificial intelligence technology, many fields are actively promoting the digital transformation of industries. As the key area of Chinese infrastructure to promote clean coal production and efficient green transformation, using the digital twin technology to promote the overall perception of new energy power stations, intelligent decision-making and dynamic prediction has become a new research hotspot. Through the intelligent acquisition in the perception layer, intelligent integration in the data layer and intelligent decision making in the service layer, we can set up a whole set of super short-term forecasting system and dispatching decision support system for new energy power stations, which can improve the operational efficiency. From hindsight to foresight, It’s an innovative imporve to promote the construction of smart power grid and digital power grid by effectively solving the abandon of wind and irradiance, reducing the cost of power generation and ensuring the stable operation of the whole power grid.

The rate coefficients for dielectronic recombination (DR) of lithium-like 40Ca17+ ions with ∆n = 0 core excitations are derived from electron–ion recombination spectra measured with merged-beams method at the heavy-ion storage ring CSRm. The experimental DR spectrum, in the electron–ion collision energy range of 0 to 42 eV in the center-of-mass frame, comprises of all DR resonance peaks belong to the 2s 2 S 1/2 → 2p 2 P 1/2, 3/2 core excitations. The resonant energies and strengths for the resolved resonances in 2pjnl series are determined by fitting of the measured DR peaks. The further interpretation of the measured DR rate coefficients has been performed by calculating the DR rate coefficients with relativistic configuration-interaction method implemented in flexible atomic code (FAC) and compared with the experimental results. The experimental results and FAC calculations are found to be in a good agreement within the experimental uncertainties. Moreover, temperature dependent plasma rate coefficients were constructed from 4 × 103 to 1 × 107 K energy region by convoluting experimental and theoretical DR rate coefficients with the Maxwellian energy distribution function and then compared with previously available data. The plasma DR rate coefficient is found to be significantly underestimated by the early theoretical data calculated by Jacobs et al, and Mazotta et al in the low temperature. In contrast, a very good agreement has been found between the theoretical DR data of Gu and Colgan et al and the presently measured results at the low temperature region. Therefore, the results in this work composed of a bench-mark data set for plasma modeling at the photoionized temperature range. We have also provided a fit to our measured and theoretical plasma rate coefficients for low temperature plasma modeling.

The concept of sustainable development promotes the development of new energy power generation industry. At the same time, in the field of wind power, wind curtailment and power limit gradually appear, and the output prediction of power plants has become one of research hotspots. Because of the wake effect between wind farms, the wind speed of the wind tower can not represent the real numerical value. Therefore, in this paper, we established various wake models of wind farm group under different wind direction to modify the wind speed of wind tower and get more accurate results. We also used the Long Short-Term Memory network (LSTM) to forecast the wind farm output, and finally obtained excellent forecast results. Compared with traditional prediction algorithm, it had improved the prediction accuracy.

The high-temperature special flight test is one of the important special meteorological flight tests for civil aircraft airworthiness certification flight test, and generator high-temperature cooling flight test is also very important as the key flight test subject of high-temperature special flight test. The purpose of this paper is to summarize and study the airworthiness background, technical research, technical preparation, technical implementation, and data analysis results of a certain type of civil aircraft generator high-temperature cooling flight test, to provide guidance and help for subsequent civil aircraft generator high-temperature cooling flight test.

After years of development, geophysical exploration in macro programming environment through the Internet of things has become a basic international model and has been widely valued and studied. Because of its special advantages in practice, the research of new geophysical methods and technologies has been introduced into the education of computer, law, economics, engineering and other disciplines. With the development of network technology, geophysical exploration of engineering and environment has been combined with network technology, forming problem-oriented research in network environment. In the continuous exploration, there is a stable inertia and activity process between the various elements, which can effectively find problems and solve problems. Therefore, through the Internet of things, this effective bridge combines engineering and environment with “new geophysical methods and technologies” to explore and develop new fields[1].

The computer measurement control system ensures the safe and normal operation of the equipment in urban survey. If we want the equipment to be able to contribute its own role in a long period of time, we must timely maintain the safety performance of the computer measurement control system to ensure its stability and security. Make the equipment better for urban measurement to provide more efficient, more favorable, more accurate service. With the development of computer technology, the experience of using computer technology in surveying and mapping circles at home and abroad shows that it has great advantages to process survey information by computer. In this paper, several of the most common computer technology used in urban survey are selected and discussed.

The Reynolds averaged Navier-Stokes models are still the workhorse in current engineering applications due to its high efficiency and robustness. However, the closure coefficients (also known as model parameters) of turbulence models are calibrated by model builders according to some fundamental flows, and the values suggested by the model builders may not be applicable to all flow types. In this work, the Bayesian method is applied to recalibrate the closure coefficients of SA turbulence model to improve its performance in backward-facing step problem. The results show that the four parameters Cb1, Cw3, Cv1 and κ are well informed by the experimental data of skin friction coefficient. The recalibrated model parameters show better performance than the nominal values in the prediction of skin fiction coefficient.

In order to measure the Universal Time (UT1) in real time, National Time Service Center (NTSC) has built a VGOS-like (VLBI Global Observing System) broadband VLBI network, which includes three 13-m radio telescopes located in Jilin, Sanya and Kashi, and a data analysis center in Xi’an. Each station is equipped with a highly stable hydrogen atomic clock and a self-developed VLBI backend, and is colocated with two GPS receivers. This VGOS-like VLBI network may play an important role in improving the Chinese broadband VLBI technology and making valuable contributions to domestic VLBI measurements of UT1. In this paper, we introduce the specifications of this VLBI network, and present the UT1 measurements at C-band conducted in 2018 using the Jilin-Kashi baseline of this network. The comparisons between our UT1 estimates and those provided by IERS suggest that the NTSC VLBI network is capable to determine UT1 accurate at the level of 58.8 μs.

For the purpose of greenhouse gas control and environment protection, CO2 emission reduction has become a hot spot in global research. CO2-EOR and geological storage are widely regarded as one of the most economical and promising emission reduction measures. In this paper, the 3D embedded discrete fracture model (EDFM) is built to simulate the interfracture CO2 flooding and geological storage process in fractured reservoirs. This model can deal with the complex geological conditions of three-dimensional arbitrary inclined fracture networks, significantly improve the calculation efficiency, and accurately evaluate the CO2-EOR process of real reservoirs. The obtained CO2 reserves and saturation distribution can provide key technical parameters for field operations.

Recombination of Ar14+, Ar15+, Ca16+, and Ni19+ ions with electrons has been investigated at low energy range based on the merged-beam method at the main cooler storage ring CSRm in the Institute of Modern Physics, Lanzhou, China. For each ion, the absolute recombination rate coefficients have been measured with electron–ion collision energies from 0 meV to 1000 meV which include the radiative recombination (RR) and also dielectronic recombination (DR) processes. In order to interpret the measured results, RR cross sections were obtained from a modified version of the semi-classical Bethe and Salpeter formula for hydrogenic ions. DR cross sections were calculated by a relativistic configuration interaction method using the flexible atomic code (FAC) and AUTOSTRUCTURE code in this energy range. The calculated RR + DR rate coefficients show a good agreement with the measured value at the collision energy above 100 meV. However, large discrepancies have been found at low energy range especially below 10 meV, and the experimental results show a strong enhancement relative to the theoretical RR rate coefficients. For the electron–ion collision energy below 1 meV, it was found that the experimentally observed recombination rates are higher than the theoretically predicted and fitted rates by a factor of 1.5 to 3.9. The strong dependence of RR rate coefficient enhancement on the charge state of the ions has been found with the scaling rule of q 3.0, reproducing the low-energy recombination enhancement effects found in other previous experiments.

Electrode materials that can function well in both lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) are desirable for electrochemical energy storage applications, especially under high rate. In this work, a three-dimensional (3D) mesoporous γ-Fe2O3@carbon nanofiber (γ-Fe2O3@CNF) mat has been successfully synthesized by sol-gel based electrospinning and carbonization. It delivers a specific capacity of 820 mAh g-1 at 0.5 C after 250 cycles, 430 mAh g-1 at 6 C after 1000 cycles, and 222 mAh g-1 at ultrahigh rate of 60 C for LIBs, while for SIBs it delivers a specific capacity of 360 mAh g-1 at 1 C after 1000 cycles and 130 mAh g-1 at 60 C. Besides, the result of ex situ microstructure examination shows the polycrystalline nature of γ-Fe2O3 nanoparticle still exists in LIB even after 1000 cycles, while it vanishes in SIB, suggesting that the relatively larger volume expansion occurred during Na+ insertion/deinsertion, resulting in pulverization of the particles. The CNFs maintained their pristine 3D network structure after the charge/discharge, which demonstrated the critical role of a robust conductive electrode in promoting fast Li+/Na+ transportation. More importantly, they act as an electrical bridge between Li+/Na+ and γ-Fe2O3 nanoparticles, therefore suppressing the cell impedance growth and γ-Fe2O3 volume expansion, resulting in the enhancement in both cyclic and rate capability.

Synopsis At the main cooler storage ring (CSRm) of IMP, Lanzhou, we have measured merged-beams rate coefficients for dielectronic recombination (DR) of F-like Ni in the energy range 0-160 eV which comprises all DR resonances associated with ΔN = 0 core excitations. We compare our results with calculations by the flexible atomic code (FAC). Good agreement is found between calculated and measured resonance parameters except for the low-energy 2s 2p6 (2S1/2)61 resonances. In addition, we have also derived plasma rate-coefficients from our data for applications in astrophysics.

The ceramics La0.85Cr0.15TiO x and La0.7Cr0.3TiO x are prepared by conventional solid-state reaction method. The dielectric properties of Cr-doped LaTiO x as a function of frequency (0.1 kHz ≤ f ≤ 1 MHz) and temperature (77 K ≤ T ≤ 360 K) are studied. The blocks are then annealed in a flowing O2 or Ar/H2 to convert their oxygen content and the tests mentioned above are performed. The highly oxygenated samples exhibit extremely high low-frequency dielectric constants at room temperature (~106). The results show that the oxygen stoichiometry could significantly influence the dielectric properties of Cr-doped LaTiO x .

This work investigated the selection of beam margins in lung-cancer stereotactic body radiotherapy (SBRT) with 6 MV photon beams. Monte Carlo dose calculations were used to systematically and quantitatively study the dosimetric effects of beam margins for different lung densities (0.1, 0.15, 0.25, 0.35 and 0.5 g cm(-3)), planning target volumes (PTVs) (14.4, 22.1 and 55.3 cm3) and numbers of beam angles (three, six and seven) in lung-cancer SBRT in order to search for optimal beam margins for various clinical situations. First, a large number of treatment plans were generated in a commercial treatment planning system, and then recalculated using Monte Carlo simulations. All the plans were normalized to ensure that 95% of the PTV at least receives the prescription dose and compared quantitatively. Based on these plans, the relationships between the beam margin and quantities such as the lung toxicity (quantified by V20, the percentage volume of the two lungs receiving at least 20 Gy) and the maximum target (PTV) dose were established for different PTVs and lung densities. The impact of the number of beam angles on the relationship between V20 and the beam margin was assessed. Quantitative information about optimal beam margins for lung-cancer SBRT was obtained for clinical applications.

Quality assurance (QA) for intensity-modulated radiation therapy (IMRT) treatment planning and beam delivery, using ionization chamber measurements and film dosimetry in a phantom, is time consuming. The Monte Carlo method is the most accurate method for radiotherapy dose calculation. However, a major drawback of Monte Carlo dose calculation as currently implemented is its slow speed. The goal of this work is to bring the efficiency of Monte Carlo into a practical range by developing a fast Monte Carlo monitor unit (MU) verification tool for IMRT. A special estimator for dose at a point called the point detector has been used in this research. The point detector uses the next event estimation (NEE) method to calculate the photon energy fluence at a point of interest and then converts it to collision kerma by the mass energy absorption coefficient assuming the presence of transient charged particle equilibrium. The MU verification tool has been validated by comparing the calculation results with measurements. It can be used for both patient dose verification and phantom QA calculation. The dynamic leaf-sequence log file is used to rebuild the actual MLC leaf sequence in order to predict the dose actually received by the patient. Dose calculations for 20 patient plans have been performed using the point detector method. Results were compared with direct Monte Carlo simulations using EGS4/MCSIM, which is a well-benchmarked Monte Carlo code. The results between the point detector and MCSIM agreed to within 2%. A factor of 20 speedup can be achieved with the point detector method compared with direct Monte Carlo simulations.

There are several localization techniques that have been used for prostate treatment. Recently, the potential use of a variety of CT-based equipment in the treatment room has been discussed. The goal of our study was to develop an automated procedure for daily treatment table shift calculation based on two CT data sets: simulation CT data and localization CT data. The method suggested in this study is a 3D image cross-correlation of small regions of interest (ROI) within the two data sets. The relative position of the two ROIs with respect to each other is determined by the maximum value of the normalized cross-correlation function, calculated for all possible relative locations of the two ROIs. After the best match is found the shifts are given by the vector connecting the treatment isocentre and the planning isocentre (both determined by the radio opaque fiducial markers on the patient's skin). The results have been compared with shifts calculated through manual fusion. The shift differences, averaged over 17 statistically independent shift calculations, are less then 1 mm in the lateral and longitudinal directions, and about 1 mm in the AP direction. The impact of image noise on the performance of the algorithm has been tested. The results show that the algorithm accurately adjusts for target positional changes even with Gaussian noise levels as high as 20% inserted.

Monte Carlo simulation of radiation transport is considered to be one of the most accurate methods of radiation therapy dose calculation. With the rapid development of computer technology, Monte Carlo based treatment planning for radiation therapy is becoming practical. A basic requirement for Monte Carlo treatment planning is a detailed knowledge of the radiation beams from medical accelerators. A practical approach to obtain the above is to perform Monte Carlo simulation of radiation transport in the medical accelerator. Additionally, Monte Carlo modelling of the treatment machine head can also improve our understanding of clinical beam characteristics, help accelerator design and improve the accuracy of clinical dosimetry by providing more realistic beam data. This paper summarizes work over the past two decades on Monte Carlo simulation of clinical electron beams from medical accelerators.

Restricted mass collision stopping-power ratios for electron beams from a scatter-foil medical linear accelerator (Varian Clinac 2100C) were calculated for various combinations of beams, phantoms and detector materials using the Monte Carlo method. The beams were of nominal energy 6, 12 or 20 MeV, with square dimensions 1 x 1 cm2 to 10 x 10 cm2. They were incident at nominal SSDs of 100 or 120 cm and inclined at 90 degrees or 30 degrees to the surface of homogeneous water phantoms or water phantoms interspersed with layered lung or bone-like materials. The broad beam water-to-air stopping-power ratios were within 1.3% of the AAPM TG21 protocol values and consistent with the results of Ding et al to within 0.2%. On the central axis the stopping-power ratio variations for narrow beams compared with normally incident broad beams were 0.1% or less for water-to-LiF-100, graphite, ferrous sulfate dosimeter solution, polystyrene and PMMA, 0.5% for water-to-silicon and 1% for water-to-air and water-to-photographic-film materials. The transverse variations of the stopping-power ratios were up to 4% for water-to-silicon, 7% for water-to-photographic-film materials and 10% for water-to-air in the penumbral regions (where the dose was 10% of the global dose maximum) at shallow depths compared with the values at the same depths on the central axis. In the inhomogeneous phantoms studied, the stopping-power ratio correction factors varied more significantly for air, followed by photographic materials and silicon, at various depths on the central axis in the heterogeneous regions. For the simple layered phantoms studied, the estimation of the stopping-power ratio correction factors based on the relative electron-density derived effective depth approach yielded results that were within 0.5% of the Monte Carlo derived values for all the detector materials studied.

The paper presents Fricke-to-water dose conversion and wall correction factors for Fricke ferrous sulphate dosimetry in high-energy electron beams. The dose conversion factor has been calculated as the ratio of the mean dose in water to the mean dose in the Fricke solution with a water-walled vessel and the wall correction factor accounts for the change in the Fricke dose due to the presence of the non-water wall material. The EGS4 (electron gamma shower version 4) Monte Carlo code system has been employed in the work together with the application of a correlated sampling variance reduction technique. The results show that for a Fricke dosimeter of 1.534 cm diameter and 5.5 cm length the dose conversion factor is nearly constant at 1.004 (within 0.1%) for electron energies of 11-25 MeV if the dosimeter is placed at the depth of maximum dose but can vary by a few per cent if the dosimeter is placed on the descending portion of the depth-dose curve.

The authors present the Monte Carlo calculated central electrode correction factors for cylindrical ionization chambers used in high-energy photon and electron beams. The EGS4 code system with the application of a correlated sampling variance reduction technique has been employed in the calculation of the response of ionization chambers of different size and material. The results show that for an NE2571 chamber with a 1 mm diameter aluminium electrode the chamber response is increased by 0.6% in a 60Co beam and 0.4% in a 24 MV beam compared to a graphite electrode. In a 60Co beam the effect of an aluminium electrode compared with a graphic electrode increases with diameter from about 0.6% for 1 mm diameter to 3.4% for 5 mm diameter. The hollow aluminium electrode in an NE2561 chamber increases the chamber response by about 0.6% in a 60Co beam compared to an air electrode. For electron beams the electrode effect varies with incident electron energy and phantom depth.

The use of liquid crystal displays (LCDs) has become prevalent in our modern, technology driven society. We demonstrate a linearly polarized GaInN light-emitting diode (LED) embedded with a wire-grid polarizer (WGP). A derivation of rigorous coupled-wave analysis is given; starting from Maxwell?s equations and finishing by matching the boundary conditions in the grating and other regions of interest. Simulated results are shown for various grating parameters, including different metals used for the grating and the metal-line dimensions. An LED fabrication process is developed for demonstrating WGP-LEDs. A clear polarization preference for the light coming out of the WGP-LED is experimentally demonstrated with a polarization ratio over 0.90, which is in good agreement with simulation results.

We demonstrate a cryogenic cooled Yb:YAG disc laser amplifier with V-shape and active-mirror configuration, end-pumped by InGaAs laser diode array. It consists of a cryogenic Yb:YAG regenerative amplifier and an additional six-pass Yb:YAG disc amplifier. Performances of the laser amplifier at low temperature over a range of 80–280 K are investigated theoretically and experimentally. A maximum output energy of 442 mJ, 10 ns pulses at a 10 Hz repetition rate is obtained for the laser in six-pass amplification at 120 K temperature; the corresponding optical-to-optical efficiency is 17.3%.

Total recombination rate coefficients of Sn-112(35+) ions have been firstly measured by employing the electron-ion merged-beams technique on the main cooler storage ring at Lanzhou. Using an electron beam energy detuning system, we precisely tuned the relative energies from 0 to 6.0 eV between the electron beam and the ion beam (momentum spread Delta p/p similar to 5 x 10(-4)). A multi-configuration Breit-Pauli calculation utilizing kappa-averaged relativistic orbitals has been carried-out for the recombination rate coefficients. We find that there are obvious differences between the experimental total rate coefficients and the theoretical calculations.

Ternary semiconducting AgSbTe2 nanowire arrays were synthesized for the first time by using the direct-current electrodeposition technique. X-ray diffraction, scanning electron microscopy, energy dispersive spectrometry, and transmission electron microscopy analyses indicate that the nanowire arrays are high filling, ordered, single crystalline and the nanowires have a highly preferential orientation grown along the [100] direction. Annealing studies show that compared with other temperatures, annealing at 100°C can significantly increase the crystallinity of AgSbTe2 nanowires. The optical absorbance spectra of the AgSbTe2 nanowire arrays show that the optical band gap has a strong blue shift with decreasing the diameter of the nanowire.

The longitudinal Schottky spectra of a radio-frequency (RF) bunched and electron cooled 22Ne10+ ion beam at 70 MeV/u have been studied by a newly installed resonant Schottky pick-up at the experimental cooler storage ring (CSRe), at IMP. For an RF-bunched ion beam, a longitudinal momentum spread of has been reached with less than 107 stored ions. The reduction of momentum spread compared with coasting ion beam was observed from Schottky noise signal of the bunched ion beam. In order to prepare the future laser cooling experiment at the CSRe, the RF-bunching power was modulated at 25th, 50th and 75th harmonic of the revolution frequency, effective bunching amplitudes were extracted from the Schottky spectrum analysis. Applications of Schottky noise for measuring beam lifetime with ultra-low intensity of ion beams are presented, and it is relevant to upcoming experiments on laser cooling of relativistic heavy ion beams and nuclear physics at the CSRe., Comment: to be published in Chinese Physics C

A storage ring equipped with an electron cooler is an ideal platform for dielectronic recombination (DR) experiments. In order to fulfill the requirement of DR measurements at the main Cooler Storage Ring, a detuning system for the precision control of the relative energy between the ion beam and the electron beam has been installed on the electron cooler device. The test run using 7.0 MeV/u C6+ beam was performed with recording the Schottky spectra and the ion beam currents. The influence of pulse heights and widths of the detuning voltage on the ion beam was analyzed. For the small pulse height, the experimental results from the Schottky spectra were in good agreement with the theoretical results. The frequency shift in the Schottky spectra was significantly reduced for the short pulse width. For the large pulse height, an oscillation phenomenon was observed and some effective ways to reduce the oscillation were pointed out. The detailed description of the phenomenon and the theoretical model based on the plasma oscillation is discussed in this paper. The overall results show that the new detuning system works properly, and could fulfill the requirements of future DR experiments.

An electron beam energy detuning system has been installed to the electron cooler device at the cooler storage ring in Lanzhou. The system is tested by using 7 MeV/u C6+ beam. The detuning system is feasible for future dielectronic recombination experiments.