Wan Hong

Development of a high mass-resolution TOF-ERDA system for a wide mass range

A high mass-resolution TOF-ERDA system installed at RILAC of RIKEN is presented. The target chamber was designed for TOF-ERDA. A charged-particle detector and a time detector for TOF measurements were installed in the chamber. The data-acquisition system, comprising CAMAC modules, is controlled by a personal computer. The analysis of the spectra is performed off-line. The mass resolution of the system for masses of around A = 28 was evaluated to be 1.9. H, C, N and O in a PIQ film could be measured simultaneously, and the peaks of C, N and O were separated.

A wavelength dispersive X–ray spectrometer for small area X–ray fluorescence spectroscopy at SPring–8 BL39XU☆

A wavelength dispersive X-ray spectrometer is designed and developed for X-ray fluorescence analysis and spectroscopy using an X-ray microprobe at SPring‐8 BL39XU. The spectrometer uses a flat analyzer crystal, and X-rays from a small beam spot are dispersed by the crystal onto a position sensitive proportional counter. The energy resolution of the spectrometer is determined by the spatial resolution of the position sensitive proportional counter, and the additional use of the slit-scan can improve the energy resolution if necessary. Performance of the spectrometer is evaluated by using a conventional X-ray source, and preliminary experimental results of the X-ray microprobe by using brilliant hard X-rays from an X-ray undulator are reported. q 1999 Elsevier Science B.V. All rights reserved.

Improvement in the detection limits of elastic recoil detection analysis (ERDA) using a time-of-flight detection

The detection limits of oxygen and silicon in a SiO2 sample were compared between a time-of-flight elastic recoil detection analysis (TOF-ERDA) and conventional ERDA using a 41.5 MeV 40Ar ion beam. With TOF-ERDA, an energy spectrum of each mass can be extracted by measuring both the flight time and the energy of each recoil particle while conventional ERDA provides an overlapped energy spectrum fo all masses. It was found that the oxygen can be detected at areal densities of as low as 6.62×1013 atoms/cm2 by TOF-ERDA, and that the detection limits can be improved by the factor of 5 compared to conventional ERDA.

Extremely fast decay component of UV luminescence from 2-MeV/amu ion irradiated alumina

Abstract Luminescence spectra and their decay curves are measured for α-alumina irradiated by various ions and at various temperatures. The luminescence spectra show several bands in addition to the 3.8-eV band being well-known electron and photon irradiation. The decay curves and time-resolved spectra show enhanced decay of the 3.8-eV band and a new extremely fast decay component at about 400 nm which has a half lifetime of 100 ps or less.

Determination of the Mass Resolution and the Depth Resolution of Time of Flight Elastic Recoil Detection Analysis Using Heavy Ion Beams

The mass resolution and the depth resolution of the time of flight elastic recoil detection analysis (TOF-ERDA) system for a Si wafer sample 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 au for 41.5 MeV Ar to 3.32 for 22.6 MeV Ar. Also, the depth resolutions were determined from 1.67×1017 atoms/cm2 for 20.0 MeV Ne to 2.67×1017 atoms/cm2 for 138.1 MeV Xe near to the sample surface. The advantages of each probe ion were compared. A superconductor sample, YBa2Cu3O7-x , was measured using Ar accelerated to 41.5 MeV; Y, Ba, Cu and O were clearly separated.