A. V. Barnes

Interaction of slow, very highly charged ions with surfaces

The present article reviews recent advances in the studies of the interaction of slow (v < vBohr), very highly charged ions (such as Xe 52+ and Au 69+ ) with surfaces of metals, semiconductors, and insulators (including biological materials). After a brief summary of past developments, we describe key experimental techniques for studies of secondary particle emission and the de-excitation dynamics of the highly charged ions. Recent progress in measurement and determination of the mechanisms leading to secondary electron yields, secondary ion yields and total sputtering yields will be discussed. The deexcitation dynamics are addressed in experiments on projectile neutralization and energy loss in thin films of material. We review the theoretical concepts briefly and introduce theoretical models in the discussion of experimental results. Following the presentation of fundamental studies we will address emerging applications of slow, very highly charged ions in surface analysis and surface modification. # 1999 Published by Elsevier Science Ltd. All rights reserved.

Electronic sputtering of solids by slow, highly charged ions: Fundamentals and applications

Electronic sputtering in the interaction of slow (v < vBohr), highly charged ions (SHCI) with solid surfaces has been subject of controversial discussions for almost 20 years. We review results from recent studies of total sputtering yields and discuss distinct microscopic mechanisms (such as defect mediated desorption, Coulomb explosions and eAects of intense electronic excitation) in the response of insulators and semiconductors to the impact of SHCI. We then describe an application of ions like Xe 44a and Au 69a as projectiles in time-of-flight secondary ion mass spectrometry for surface characterization of semiconductors. ” 2000 Elsevier Science B.V. All rights reserved.

The effects of radiation on (1,3,5 - triamino - 2,4,6 - trinitrobenzene) TATB studied by time-of-flight secondary ion mass spectrometry

Abstract Highly Charged Ion (HCI) Time-of-Flight (TOF) Secondary Ion Mass Spectrometry (SIMS) has been employed to analyze the changes in the surface composition of TATB caused by low energy electron, ultraviolet, and Gamma ray irradiation. Comparisons are made between canary yellow (not irradiated) TATB and TATB that has been “greened” by exposure to radiation. We ascribe the color change from yellow to green to a loss of oxygen. Another striking aspect of this study is the presence of a feature at m/z = 30 (NO+) for highly charged ion SIMS, which does not occur in singly charged ion TOF SIMS.

Ds+ decays to, +, and +

Using the CLEO II detector, we have accurately measured {ital D}{sub {ital s}} decay branching ratios relative to the {phi}{pi}{sup +} mode for the {eta}{pi}{sup +} and {eta}{prime}{pi}{sup +} states, for which there are conflicting claims; our results are 0.54{plus minus}0.09{plus minus}0.06 and 1.20{plus minus}0.15{plus minus}0.11, respectively.

Study of D sup 0 decays into final states with a. pi. sup 0 or. eta

We have made measurements of decay modes of neutral {ital D} mesons into exclusive final states containing photons using data collected with the CLEO detector at the Cornell Electron Storage Ring. We report observation of {ital D}{sup 0}{r arrow}{ital K}{sup {minus}}{pi}{sup +}{pi}{sup {minus}}{pi}{sup +}{pi}{sup 0} (charge conjugates are implicit), and present new measurements of the branching ratios for {ital D}{sup 0}{r arrow}{ital K}{sup {minus}}{pi}{sup +}{pi}{sup 0}, {ital D}{sup 0}{r arrow}{ital {bar K}}{sup 0}{pi}{sup +}{pi}{sup 0}{pi}{sup {minus}}, {ital D}{sup 0}{r arrow}{ital {bar K}}{sup 0}{pi}{sup 0}, {ital {bar K}}{sup *0}{eta}, and {ital D}{sup 0}{r arrow}{ital {bar K}}{sup 0}{omega}. Where possible, results are compared with theoretical predictions for two-body {ital D}{sup 0} decays.