ERDA MEASUREMENT OF HYDROGEN ISOTOPES WITH A DELTA-E-E TELESCOPE

A DELTAE-E telescope for mass separation of the isotopes of hydrogen i s described for a He-4 bombarding energy of 4.0 MeV. The use of a 13.6 mum Si transmission detector as DELTAE detector enabled the separatio n of ERDA signals from the three isotopes of hydrogen in thick samples containing hydrogen (H), deuterium (D) and tritium (T). Whereas a DEL TAE detector is normally used as an atomic charge (Z) separator in hea vy ion spectroscopy, in this study it was used to separate the differe nt masses of the hydrogen isotopes. H events were fully separated from the other isotopes and the separation between D and T events was such that more than 95% of the signals corresponding to the two isotopes c ould be extracted for analytical purposes, with the maximum depth info rmation obtainable for a single isotope being about 4.1 x 1018 Ti at./ cm2 for H, 5.3 x 10(18) Ti at./cm2 for D and 4.8 x 10(18) Ti at./cm2 f or T. The technique, which is especially useful in targets containing all the isotopes of hydrogen, is illustrated by means of a study of th e depth distribution of hydrogen isotopes in solid thick TiD(x) and Ti T(x) targets.