Development of a High Mass-Resolution TOF-ERDA System for a Wide Mass Range from Hydrogen

Elastic recoil detection analysis (ERDA) is one of the most promising methods for determination of light and medium elements in a heavy matrix, such as trace hydrogen analysis. Though a conventional ERDA employing a stopper foil in front of the detector has been performed at RIKEN[1,2], a new ERDA system using time of flight (TOF) detection was set up to realize both higher mass reso-lu-tion and lower detection limit. The TOF spectrometer using a charged-particle detector and a time detector, and the data-acquisition system comprising CAMAC modules and a personal computer were installed. The mass resolution and the depth resolution of the system for a Si wafer have been determined using 20Ne, 40Ar and 136Xe ions as probes. The incident energies were 20.0 MeV for Ne, 41.5 MeV and 22.6 MeV for Ar and 138.1 MeV for Xe, respectively. The mass resolutions of Si were found to be from 1.90 for 41.5 MeV Ar to 3.32 for 22.6 MeV Ar. Also, the depth resolutions were determined from 167 (10 x 15/cm2 ) for 20.0 MeV Ne to 267 (10 x 15/cm2 ) for 138.1 MeV Xe near to the sample surface. A PIQ film and a superconductor sample, YBa2Cu3O7-x, were measured using Ar accelerated to 41.5 MeV. H, C, N and O in the PIQ film and Y, Ba, Cu and O in the superconductor sample could be measured simultaneously and were clearly separated.

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