ELECTRON DETECTOR

摘要

PURPOSE: To provide an electron detector whose collection and detection of back scattered electrons is enhanced by equipping it with an energy filter for blocking secondary electrons emitted from a test piece. CONSTITUTION: An electron detector 100 is equipped with an energy filter for blocking secondary electrons emitted from a test piece 102 so that only backscattered electrons reach an electron multiplier. The energy filter can accomplish its objective most effectively by providing a generally ring electrode 112 which is biased with a negative electric potential with respect to the test piece 102 and setting the potential difference between a center of its opening 114 and the test piece 102 to be -50 V or less.