Development Of Time-of-flight Mass Spectrometry And Negative Ion Photoelectron Imaging Instrument

More and more attention has been paid to the research of free radicals and their precursors.The Time-of-flight mass spectrometry and photoelectron imaging technology are one of the important ways to carry out the related research.On this basis,combined with the relevant theoretical knowledge,our laboratory independently designed and built a set of photoelectron imaging instrument combining laser sputtering source time-of-flight mass spectrometry and negative ions.The advantage of this instrument is that it can carry out high-resolution velocity imaging exploration for the research objects such as free radical anion precursor,reaction product anion,cluster product,etc.This paper mainly introduces the theoretical basis,design ideas,parts processing and assembly,debugging and optimization of the instrument,performance test of the instrument and the research on acetone anion using the instrument.The instrument was debugged with copper to optimize the TOF-MS and improve the resolution.The full width at half maximum of the mass spectrum isΔT=20ns,and the resolution can reach 350.The photoelectron spectrum of the instrument is also tested by using Cu^-,and the experimental results show that the instrument meets the expectation.After the test,the photoelectron imaging of CH₃COCH₂^-was carried out.And the photoelectron spectrum was obtained.The experimental values of adiabatic electron desorption energy（ADE）and vertical desorption energy（VDE）of CH₃COCH₂^-were1.64（2）e V and 1.74（2）e V respectively.