Patent ID: 9082586
Filing Date: 2015-07-14
Classification: B82Y,H01J

Abstract:
1. A cathode operating temperature adjusting method comprising: acquiring an approximate equation that approximates a correlation between a value of an emission current in an electron beam source using a cathode and an operating temperature of the cathode at which a bias voltage becomes saturated at the emission current; measuring a current density of an electron beam emitted from the cathode when in a state in which an n-th emission current value, where n is a natural number, and an n-th operating temperature of the cathode are set in the electron beam source; determining whether the current density measured is within a range of a first tolerance; changing the n-th emission current value, which has been set, to an (n+1)th emission current value when the current density measured is not within the range of the first tolerance; calculating an operating temperature of the cathode corresponding to the (n+1)th emission current value by using the approximate equation; setting the operating temperature calculated, as an (n+1)th operating temperature of the cathode, in the electron beam source; measuring an operating temperature of the cathode at which a bias voltage becomes saturated at a maximum emission current value to be permitted; and measuring an operating temperature of the cathode at which a bias voltage becomes saturated at a minimum emission current value to be permitted, wherein the approximate equation is acquired by using the operating temperature of the cathode corresponding to the maximum emission current value and the operating temperature of the cathode corresponding to the minimum emission current value.