HOLD-UP AND MEMORY EFFECT FOR CARBON IN A COMPACT MICROWAVE ION-SOURCE

The production of C+ in a microwave ion source injected with a gaseous CO2 sample has been investigated as an alternative to sample graphiti zation, A continuous flow of argon gas maintained the discharge, and 2 0 mu L Of CO2 gas at approximately 1 atm was pulsed into the source th rough a sample valve closely coupled to the plasma chamber, The C+ com ponent of the beam fell to 1% of its original intensity less than 10 s after the valve was operated. in a separate experiment, the microwave ion source was operated with pure CO2 feed gas and the extracted beam was magnetically analyzed. Efficient breakup of the molecules was obs erved. These results are considered promising for such applications as accelerator mass spectrometry of C isotopes in gaseous samples.