.4 The Mv Ion Electrostatic Accelerator Development

This article is carried out to cooperate with the development of 4MV ion electrostatic accelerator. So it has respectively studied the assembling and sealing technological process of ion accelerating tube, the influence of the physical parameters of RF ion source on the quality of ion beam, the effects of the composition and pressure of insulating gas on the highest voltage of electrostatic accelerator, the measures against interference adopted in controlling system, etc. The phenomena and problems appearing in developing process of the electrostatic accelerator are analyzed and solved also. The details are as follows.The assembling and sealing technological process of ion accelerating tube is studied. The vacuum of the debugged tube is 6 × 10^-5 Pa; the parallel degree is 0.1 mm; and the highest voltage between electrodes is above 18 kV/cm. It is found and explained that there is a pressure-resisting blind area in 67⁰.1Pa. In the debugging process, the hidden mechanical danger rising easily is found and solved.A RF ion source for electrostatic accelerator is designed and debugged. It adopts the push-pull circuit of electron tube in the inductance coupling way. Its oscillating frequency is 20 50 MHz. The influence of various factors on the RF ion source discharging is studied. Many means are adopted to improve its discharging reliability. They make the plate voltage of its oscillator degrade evidently. The discharging bottle can discharge accurately above 500V. The influence of oscillator' plate voltage, gas pressure, extraction voltage, focusing voltage and magnetic voltage on the quality of ion beam is determined and analyzed. Those are found in experiments that the ion beam intensity increases with the plate voltage rising and the proton ratio is largest at 575 V, that both the ion beam intensity and the proton ratio have the best value with gas pressure rising, that the proton ratio doesn't change and the ion beam intensity has the voltage-ampere characteristic of diode with the extraction voltage going up and that...