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Abstract:
The enhancement of a cryogenic radio frequency 22 pole trap instrument by the addition of ringelectrodes is presented in detail. The ring electrodes tightly surround the poles and only a fractionof the applied electric potential penetrates to the trap axis, facilitating the fine control of slow coldions. A precise computational model, describing the effective mechanical potential created by theapplied static and rf fields, governing the ion behaviour, is employed to demonstrate and under-stand the operation of our setup. The use of ring electrodes for improved extraction of cold storedions is shown. Variable trapping potentials, placed on one ring electrode, can be used to control theevaporation of only those H+ions from the trap, whose kinetic energy exceeds the barrier. This ringelectrode trapping opens new possibilities to study processes of minimal kinetic energy release, e. g.spin exchange. We propose a robust modified method for the determination of temperature depen-dent ion molecule reaction rates, resistant to effects caused by neutral gas freezing and demonstrateit on the reaction of CO+/CO2+with H2/D2. Finally, the use of a supercontinuum laser for quicklocalisation of spectroscopic bands is examined on the N2+Meinel system.
