Development of Time-of-Flight Mass Spectrometer for Detection of High Energy Ion and Its Application in Plasma Diagnosis

The development and improvement of instrument 14 diagnosis of high energy ion generated by the method such as vaccum discharge is very important for improving the research level of high energy plasma. In this work , a time-of-flight mass spectrometer ( TOF-MS ) for diagnosis of high-energy ion was developed , and , the qualitative analysis of high energy ions (H+, H2+, C2+, Al3+, C+, Al2+, O+ and Al+) between 10 and 150 keV was carried out on the basis of aluminum vacuum discharge ion source. The influence of pulse width and voltage of ion gate on performance of TOF-MS was optimized, and it was found that, when the pulse width was 100 ns and the accelerating voltages were 20 kV and 50 kV , respectively , the best voltages of ion gate were +/- 500 V and +/- 2500 V. Besides , it was fk)und that the mass resolution was 22 FWHM ( Full width at half maximum) when the accelerating voltage was 50 kV. Temporal variation of intensity of different ions was further studied by changing the delay time of pulse of ion gate.