Development of a High Mass-Resolution TOF-ERDA System for a Wide Mass Range from Hydrogen to Middle Heavy Elements

Abstract

A new ERDA system using time of flight (TOF) detection was set up to realize both higher mass resolution and lower detection limit in RIEKN. 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 20.0MeV for Ne, 41.5MeV and 22.6MeV for Ar and 138.1MeV for Xe, respectively. The mass resolutions of Si were found to be from 1.90 for 41.5MeV Ar to 3.32 for 22.6MeV Ar. Also, the depth resolutions were determined from 1.67×10¹⁷ atoms/cm² for 20.0MeV Ne to 2.67×10¹⁷ atoms/cm² for 138.1MeV Xe near to the sample surface. A PIQ film and a superconductor sample, Yba₂Cu₃O_7-x, were measured using Ar accelerated to 41.5MeV. 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.