Accelerator mass spectrometry with time-of-flight measurement

Abstract

A time-of-flight detection system for the measurement of microscopic concentrations of long-lived radioisotopes has been set up at the Munich MP tandem accelerator. The technique allows an unambiguous mass determination for heavy ions up to the actinides. As a first test of the system, the concentration of 129I in iodine has been measured for several samples of mineral and biological origin. The smallest 129I 127I ratios measured were a few times 10 −13. The high sensitivity of the method was achieved by using a 90° injector with a good mass resolution, a special technique of stabilizing the terminal voltage with an auxiliary beam, and a time-of-flight system with a mass resolution of 800.