Abstract
A surface ionization method was applied to the determination of the abundance ratio of copper isotopes.
For the practical point of view, the single-collector method was proved to be better than the double-collector method. The experimental conclusions on the single-collector method are as follows.
(1) The accuracy is ±0.5% (standard deviation).
(2) Copper nitrate {Cu(NO3)2} sample gives better results than copper chloride (CuCl2).
(3) The combination of a rhenium ionization filament and a tungsten vaporization filament gives the best results among the other double or single filament arrangements.
(4) The 63Cu+ ion current, the currents of ionization filament and vaporization filament, and the time from the initiation of heating of the filament to the measurement of ion-peak (63Cu+, 65Cu+) should be held constant in a series of experiments.
(5) The same ionization case should be used to compare the abundance ratio of copper isotopes.
(6) The time required for a measurement is about 2 hours.
