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The ion source is one of the key devices for the high-intensity cyclotron, which exerts influence on the beam intensity and applications of the machine. As part of the cyclotron research and development effort, China Institute of Atomic Energy (CIAE) has been developing arc discharge H- ion sources based on volume production and multi-cusp magnetic configuration since 1997. In 2000, 5.2 mA H- beam was reached and 15 mA H- beam was achieved in 2010. After a long break, H- ion source development started again in 2022 in order to improve performance of the main H- ion source of the CIAE 18 MeV cyclotron and to fulfill the requirement of future other high intensity proton beam cyclotrons for the high intensity H- ion. A new H- ion source and test stand was built at CIAE in 2023. The design of this new ion source was based on the experience on our previous 15-20 mA H- ion source and the source at TRIUMF. Major efforts included the study of the virtual filter magnetic field for filtering out fast electrons, multi-cusp confining magnetic field, four-half-circle ring filaments length and location, improvement of extraction structure and upgrading of vacuum system and power supplies. Up to now, more than 21 mA of H- beam were obtained at a high voltage of 35 kV from a plasma electrode hole of 13 mm in diameter when the hydrogen flux was 25 sccm. At this output the maximum arc power available is only 4.5 kW and the e/H- ratio is about 5. When the hydrogen flux is higher or extraction high voltage is higher, H- beam currents can reach 22 mA. However, the H- beam is very unstable with terrible sparks at extraction and acceleration gaps in this case, about five times a minute. This appears to be due to the lack of a differential pumping structure, which also results in an unexpectedly high hydrogen flux. In the experiment, the relationship between arc power and H- beam intensity was determined, also the optimal location of the four-filament structure was determined, which is obviously related to the virtual filter magnetic field distribution. At present, the emittance scanner is being processed and the measurement program is also updated and improved, the beam emittance has not been measured and analyzed at this stage. Subsequently, the vacuum chamber structure will be improved, the extraction structure also will be optimized to obtain brighter H- beam, and a long-lasting filament will be developed to reduce maintenance time.

The enterprise optimal plan model and comparative analysis are adopted in this paper to analyze the effects of pollution taxes, marketable emission permits, pollution standards and abatement subsidies on enterprise emission abatement, technology adoption incentives, the aggregate emission and the implement cost of the four environmental policy instruments. Conclusions are as follows: the major influences of enterprise abatement are technology adoption ability and the rigorousness of environmental policy; the major influences of the enterprise violation are the rigorousness of environmental policy and the government monitoring while independent of abatement technology adoption. From the technology adoption incentives, pollution standards with perfect compliance is higher than pollution standards with imperfect compliance which is higher than pollution taxes, pollution taxes is equal to abatement subsidies which is higher than tradable emission permit; from the control on the aggregate emission, on the possibility of technology improvements, pollution taxes, abatement subsidies and pollution standards will be the stone, however, tradable emission permit is the worst, if the enterprises maintain the current technology, pollution taxes, abatement subsidies, marketable pollution permits and pollution standards will have the same policy effects. From the enforcement cost of different environmental policy instruments, pollution taxes, abatement subsidies and pollution standards are the same, while tradable emission permit will be the lowest in enforcement cost. [ABSTRACT FROM AUTHOR]