摘要:

A formalism has been developed to calculate the steady-state temperature profiles induced by a cw laser in a composite system comprising a thick medium covered with a film of another medium. The analysis is carried out assuming that thermal and optical properties of the media are temperature-independent. A concept of the effective thermal conductivity for the system is introduced in terms of the maximum temperature rise. Temperature-distributions are numerically computed in typical cases for a circular Gaussian beam to illustrate dependence on film thickness, thermal conductivities and absorption coefficients of the media and size of the laser beam.

ISSN:0033-7579    

DOI:10.1080/00337578208222840

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The present state of the art of secondary ion mass spectrometry (SIMS), applied to the in-depth analysis of impurity concentration profiles, is reviewed critically. It is shown that SIMS has reached a level of perfection which is unparalleled by other analytical techniques. There are, however, several effects which may cause deviations of the measured profile from the original dopant distribution. These detrimental effects are due to interaction of primary ions with the residual gas, adsorption and incorporation of residual gases, sputtering yield variations due to the accumulation of probe atoms in the sample, mass interference between molecular ions and the atomic species under study and, last but not least, beam-induced relocation of dopant atoms (“atomic mixing”). Methods for minimizing the respective disturbing effect are discussed.

ISSN:0033-7579    

DOI:10.1080/00337578208222841

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Nuclear techniques (Rutherford back-scattering and nuclear reactions) appear very useful in the near surface analysis of glass. These techniques offer a non-destructive method of analysis, with high depth resolution without radiation effects induced by the ion beam.

ISSN:0033-7579    

DOI:10.1080/00337578208222842

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The characteristic of the radiation emitted from relativistic positrons channelled between the major planes in single crystal have been calculated. The sharp peaks of the emission spectrum in the keV region is predicted correctly and is compared with previous calculations.

ISSN:0033-7579    

DOI:10.1080/00337578208222843

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Evolution of subsurface damage microstructures such as bubbles, dislocations and microcracks during gaseous ion implantation decreases the thermal conductivity of the implant/damage region by decreasing the mean free path of the heat carriers, electrons and phonons, due to enhanced scattering. Consequently the dissipation of the beam power dumped into the implanted surface layer is interrupted, which results in the increased effective implantation temperature. The solution of steady-state heat conduction equations corresponding to ion implantation experiments is presented to give the beam spot temperature. A comparison with experimental observations like the sudden rise of temperature at the moment of blistering, red glow of blister covers and sponge-like blister skins provides an estimation of the thermal conductivity near the critical dose for blistering. It was found that the conductivity decreases by 4 to 6 orders of magnitude from its bulk value. The role of such ion-induced temperature rise in relevance to damage microstructure and surface blistering is discussed. Furthermore, the implications for wall erosion and heat transfer in fusion reactors are outlined.

ISSN:0033-7579    

DOI:10.1080/00337578208222844

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor