Method and apparatus for control of surface potential

In a method for analyzing an electrically insulating material in which a region of a sample surface is illuminated by a beam of photons or positively charged particles to cause the emission of electrons from said region resulting in said region becoming positively charged, the steps of:

• flooding the illuminated region of the sample surface with a beam of neutralizing low energy electrons, wherein said low energy electrons are provided by an electron source which emits nearly monoenergetic electrons;
• applying a means for discharging an excess negative charge on an area of the sample surface surrounding said illuminated region, wherein said excess negative charge is created by said neutralizing low energy electron beam;
• whereby the excess negative charge which accumulates on the sample surface surrounding said illuminated region is reduced.

In a method for analyzing an electrically insulating material, positioned within a spectrometer chamber, in which a region of a sample surface is illuminated by a beam of photons or positively charged particles to cause the emission of electrons from said region resulting in said region becoming positively charged, the steps of:

• flooding the illuminated region of said sample surface with a beam of neutralizing low energy electrons;
• the source of said electrons having a positive potential with respect to said spectrometer chamber to increase the electron flux to the sample surface and
• applying a means for discharging an excess negative charge charge on an area of said sample surface surrounding said illuminated region, wherein said excess negative is created by said neutralizing low energy electron beam.

A device for establishing a nearly uniform surface region potential on a specimen mounted in an x-ray photoelectron spectrometer and illuminated by an x-ray beam to cause an emission of electrons for spectroanalysis, consisting of:

• (a) means for flooding said illuminated region of said specimen surface with a beam of neutralizing low energy electrons;
• (b) means for discharging a resulting negative charge of an area adjacent to the illuminated region of said specimen wherein said resulting negative charge is created by said neutralizing low energy electron beam;
• whereby the repelling of the electrons in the neutralizing beam is reduced, and the surface potential is reduced and maintained in a uniform state to permit enhanced measurement of the emissions from the sample surface.