Microbeam elastic recoil detection of hydrogen and deuterium with applications in transition metals.

摘要

The work in this dissertation represents a substantial pioneering effort to observe and measure hydrogen in materials on a microscopic level in 3 dimensions. Hydrogen is detected using the elastic recoil detection (ERD) technique with an MeV ion microbeam. ERD maps of microscopic hydrogen and deuterium targets were made with 1 micron resolution and sensitivity of 0.1 At% in transition metals. Depth profiling is determined from the ERD energy spectrum using an energy spectrum computer simulation which can simulate ERD spectra for a multi-element, multi-layer substrate with variable hydrogen or deuterium concentration as a function of depth penetrated by the incident probing beam. Lateral hydrogen concentration mapping is accomplished by rastering the incident ion microbeam in a scan and recording ERD events for each raster point.;The technique is clearly demonstrated for applications in transition metals. ERD maps were made of hydrogen boundaries formed by implanting hydrogen through a mask as well as hydrogen micro-dots implanted by the microbeam. It was determined that the hydrogen in these implanted regions is residual hydrogen trapped in the radiation damage of the implanting beam and not necessarily the implanted hydrogen. Other ERD maps were made of hydrogen trapped in mechanical defects and defect clusters, hydrogen in the crack path of a propagating crack, deuterium and hydrogen trapped in the radiation damage from hydrogen, deuterium or He energetic ion beams.;Second-order effects such as beam heating, radiation damage, beam divergence, and ion beam modification were examined.