Negative Ion Photoelectron Imaging System And H Negative Ion Photodetachment

The geometric structure and electronic state of negative ions are very different from neutral atoms and molecules,and their extra electrons are combined with neutral atoms and molecules through short-range potential,which makes many novel physical phenomena appear under the interaction with laser light.Combined with highresolution photoelectron imaging technology,the interaction between negative ions and laser fields can be studied,and the detachment energy and excited state energy level structure of negative ions can be accurately measured.Understand the physical process of strong field under short-range potential,and promote the development of strong field physics theory.This thesis independently designed and built a negative ion photoelectron imaging system,tested and optimized the generation,focusing and photoelectron imaging measurement of the negative ion beam source.Based on this device,we carried out a preliminary study on the photodesorption process of H negative ions.The main contents and results of the paper are as follows:Independently designed and established a negative ion photoelectron imaging system,including negative ion beam source chamber,extraction chamber,photoactive area,photoelectron imaging system and other components,and gave detailed debugging and optimization process of different parts,as well as the test and characterization of photoelectron imaging system.The H negative ion signal peak obtained after mass selection has a full width at half maximum of 0.21 ?s and an intensity of 370 m V.The diameter of the bright circular spot of the spatially focused H negative ion beam is about 5 mm.On the established experimental device,a preliminary study on the photodetachment process of H negative ions was carried out.The yields of neutral H atoms and photoelectrons generated by detachment of H negative ions and their dependence on laser parameters were measured under the action of lasers with different pulse widths(nanoseconds,femtoseconds)and different wavelengths(1064 nm,800 nm and 400 nm).The variation relationship and velocity imaging show that the established system can be used to study the interaction of negative ions and laser fields,laying a foundation for further in-depth research in the future.