Patent ID: 8276210

Claim:
A tomographic atom probe having means for applying an electrical evaporation pulse of amplitude V p and duration Δt 0 to an end of a sample which is placed at a potential V 0 , said tomographic atom probe comprising: an electrode which is placed at an initial potential V i and is configured and arranged to apply the electrical pulse to the sample; a voltage generator to produce a voltage necessary for producing a pulse of amplitude V p , the voltage generator being connected to the electrode by means of an electrical connection which can be open or closed; means for causing closure of the electrical connection in a given time τ so as to apply a voltage step V p to the electrode, these means comprising a chip of semiconductor material placed on the electrical connection between the generator and the electrode, in the vicinity of the electrode, and a first source emitting light pulses of wavelength λ 1 to the semiconductor chip, said chip becoming conductive and closing the electrical connection when it is illuminated with a light pulse of wavelength λ 1 , the conduction time being a function of the duration of the light pulse applied; means for applying a voltage step of amplitude (−V p ) to the electrode at the end of a time Δt 0 after closure of the electrical connection, so as to place the electrode at the potential V i , said means being configured so that the voltage step is applied in a time τ′ substantially equal to τ.