AN OLD-NEW TOOL FOR NUCLEAR ANALYSIS - TIME-OF-FLIGHT SPECTROMETRY

The Time-of-Flight (ToF) technique can be used for mass identification , for separation of a specified mass or for measuring the energy of a given mass particle. The instrumentation required is simple and low in cost. The method features high yield, transmission efficiency is typi cally of 5 to 20%. Even with short flight paths (5 to 10 cm), Top has adequate mass resolution (M/Delta M - 300 to 500) for identifying isot opic species. This paper examines the scope of ToF in nuclear science with examples in mass spectrometry, in mass separation and in kinetic energy measurements of fixed mass particles. An example of the latter is the energy determination of recoil nuclei. If a recoil is produced inside a solid the residual recoil energy reveals the depth from which it originates. This approach is used for profiling nitrogen via N-14( n, p)C-14. The ToF measurement of the C-14 recoil energies reveals the depth distribution of nitrogen with better than 50 Angstrom resolutio n.