Temperature Measurements and Mass Resolution in a Laser-Pulsed 3DAP

To verify recent reports suggesting that femtosecond pulses generates field evaporation by direct field enhancement mechanism, a prototype laser-pulsed 3-dimensional atom probe was used. Femtosecond laser pulsing is shown to generate surface diffusion at sufficiently high power indicating that specimen heating is an important effect. Peak temperatures estimated on the basis of the reduction in evaporation field are consistent with the observed onset of surface diffusion. Based on these results and the linear variation of evaporation voltage with laser power, the authors concluded that the mechanism of evaporation enhancement is primarily thermal for femtosecond laser pulses. Using laser-pulsed 3DAP, tungsten specimen with a high mass spectrum resolution is obtained