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A high-temperature oven based on the inductive heating technology was developed successfully at the Institute of Modern Physics in 2019. This oven features a durable operation temperature of over 2000 °C inside the tantalum susceptor. By carefully designing the oven structure, the material compatibility issue at high temperature has been successfully solved, which enables the production and routine operation of refractory metal ions with SECRAL-II (Superconducting Electron Cyclotron Resonance ion source with Advanced design in Lanzhou No. 2). To further apply this type of oven to the room temperature ECR ion sources LECR4 and LECR5 (Lanzhou Electron Cyclotron Resonance ion source No. 4 and 5), a mini-inductive heating oven has been fabricated and tested in 2020. By directly evaporating calcium oxide, some high charge state calcium beams have been produced successfully, such as 52 euA of 40Ca16+, 30 euA of 40Ca17+, and 12 euA of 40Ca18+. The detailed design and testing results will be presented and discussed. [ABSTRACT FROM AUTHOR]

To investigate the hot electron population and the appearance of kinetic instabilities in highly charged electron cyclotron resonance ion source (ECRIS), the axially emitted bremsstrahlung spectra and microwave bursts emitted from ECRIS plasma were synchronously measured on SECRAL-II (Superconducting ECR ion source with Advanced design in Lanzhou No. II) ion source with various magnetic field configurations. The experimental results show that when the ratio of the minimum field to the resonance field (i.e. Bmin/Becr) is less than ∼0.8, the bremsstrahlung spectral temperature Ts increases linearly with the Bmin/Becr–ratio when the injection, extraction and radial mirror fields are kept constant. Above this threshold Ts saturates and the electron cyclotron instability appears simultaneously. This study has also demonstrated that Ts decreases linearly with the increase of the average gradient over the ECR surface when the on-axis gradient and hexapole field strengths are constant. In addition, it is found that Ts decreases with the increase of the gradient at the resonance zone (∇Becr on axis and <∇Becr>) at relatively low mirror ratio and is insensitive to the gradient at high mirror ratio when Bmin is constant. Compared to a recent study taken on a fully superconducting ECRIS (Benitez et al 2017 IEEE Trans. Plasma Sci. 45 1746–54), in which it was concluded that Ts is only sensitive with Bmin, this article shows different results discussing the mechanisms behind the correlation of magnetic field parameters to Ts. [ABSTRACT FROM AUTHOR]

Ion source development over the last 20 years at the IMP is reviewed. For versatile purposes, several types of ion sources have been involved in the research and development work at the IMP, i.e., the highly charged ECR (Electron Cyclotron Resonance) ion source, intense microwave ion source or the 2.45 GHz intense beam ECR ion source, and laser ion source (LIS). In the development of ECR ion sources, SECRAL (Superconducting ECR ion source with Advanced design in Lanzhou), Lanzhou ECR ion source, and Lanzhou all permanent magnet ECR ion source series have been made, which can cover the operation microwave frequency range of 10–28 GHz. The LIS with an Nd:YAG laser with a maximum output energy of 8 J in 8 ns pulse duration has been developed for very intense short pulse ion beams from solid materials such as C, Ti, Ni, Ag, and so on. Microwave ion sources have been built to produce intense pulsed or direct current beams from several mA to 100 mA for either high intensity accelerators or applications. This paper will give an overview of the high intensity ion source development at the IMP, especially on the recent progress and new results, such as the status of the fourth generation ECR ion source (first fourth generation ECR ion source), the production of recorded highly charged ion beams with SECRAL sources, key technology research studies, and so on. [ABSTRACT FROM AUTHOR]

According to the requirements of ion beams extracted from an electron cyclotron resonance ion source transverse phase space coupling research and the afterglow beam property effective measurement, a pepper pot type meter called PEMiL (Pepper Pot Emittance Meter in Lanzhou) has been designed, fabricated, and commissioned to obtain the emittance of high intensity highly charged heavy ion beams. The direct current beam emittance measurement results verify the coupling property caused by the semisolenoid field. This paper also describes the scheme of multiple exposure accumulation which was applied to measure the afterglow beam property, and the transverse phase space distribution of the oxygen afterglow beam which was measured for the first time is presented. [ABSTRACT FROM AUTHOR]

Superconducting electron cyclotron resonance ion source with advanced design in Lanzhou (SECRAL) is an all-superconducting-magnet electron cyclotron resonance ion source (ECRIS) for the production of intense highly charged ion beams to meet the requirements of the Heavy Ion Research Facility in Lanzhou (HIRFL). To further enhance the performance of SECRAL, an aluminum chamber has been installed inside a 1.5 mm thick Ta liner used for the reduction of x-ray irradiation at the high voltage insulator. With double-frequency (18+14.5 GHz) heating and at maximum total microwave power of 2.0 kW, SECRAL has successfully produced quite a few very highly charged Xe ion beams, such as 10 e μA of Xe37+, 1 e μA of Xe43+, and 0.16 e μA of Ne-like Xe44+. To further explore the capability of the SECRAL in the production of highly charged heavy metal ion beams, a first test run on bismuth has been carried out recently. The main goal is to produce an intense Bi31+ beam for HIRFL accelerator and to have a feel how well the SECRAL can do in the production of very highly charged Bi beams. During the test, though at microwave power less than 3 kW, more than 150 e μA of Bi31+, 22 e μA of Bi41+, and 1.5 e μA of Bi50+ have been produced. All of these results have again demonstrated the great capability of the SECRAL source. This article will present the detailed results and brief discussions to the production of highly charged ion beams with SECRAL. [ABSTRACT FROM AUTHOR]