STUDY OF ATOM MOLECULE COLLISIONS WITH ELECTROSTATIC ION STRAGE RING

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Electrostatic ion storage rings have various advantages : 1)they can store very heavy ions, i.e., not only polyatomic molecular ions, but also cluster, DNA, and amino acid ions, which have not been previously dealt with as beams, 2)they can cool the vibrationally excited states of the molecular ions by emitting radiation during storage, and 3)their practical beam intensity is high due to circulation of beams compared with the traditional one-pass experiment, and they are suitable to merging experiments with electron, neutral and laser beams. By developing the electrostatic ion storage ring and merging experiments with other beams, we aimed to investigate a brand new field in atomic collision like lifetime of excited state of biomolecular ions or their interaction with electron, neutral, positive/negative ion, laser etc..In 2002, we constructed the ring with circumstance of about 8 m and the inside of the ring was kept in a good vacuum of 10^<-11> Torr order. Furthermore, we succeeded in cooling the ring itself down to the liquid nitrogen temperature, which is one of the most important characters of our ring. In 2003, we developed a Duoplasma-type ion source providing positive and negative ions, and prepared both a mass analyser to select ion species and a pulsed ion injection system. In addition we made a neutral product detector placed on the extension of the straight-line section, and a non-destructive beam monitor picking up the induced charge by the beam. We recently succeeded in the circulation of the heavy rare gas ions more than 1000 turns. Soon after tuning of the best operation parameters, we plan to storage molecular ions, and measure its temperature dependence of lifetime and vibrational spectroscopy using a tunable laser.