Experimental apparatus for production, cooling, and storing multiply charged ions for charge-transfer measurements

A novel method is described that combines the production of ions by laser ablation with an ion-trap technique for the measurement of thermal-energy charge-transfer rates of multiply charged ions and neutrals. The charge-transfer rate is determined by measuring the rate of loss of stored ions from the trap. Verification of the calibration of the apparatus is demonstrated through investigation of charge transfer of N2 and N2+, which has been studied by another group. We also have made the first measurement on the thermal-energy charge-transfer coefficient of Ar and W2+. The rate coefficient is 0.99(0.22)x10-11 cm3 s-1