Thermally stable electron gun arrangement with electrically non-conductive spacer members

An electron gun arrangement comprising:

• an electron gun having a longitudinal axis and including first and second electrodes spaced apart from one another along the longitudinal axis for generating an electron beam in a direction of the longitudinal axis;
• a first electrode support means for supporting the first electrode and including first slot means presenting a first pair of surfaces spaced apart from one another in the direction of the longitudinal axis;
• a second electrode support means spaced apart from the first electrode support means in the direction of the longitudinal axis for supporting the second electrode and including second slot means presenting a second pair of surfaces spaced apart from one another in the direction of the longitudinal axis, the surface of the first pair of surfaces that is closer to the second electrode support means constituting a first clamping surface and the surface of the second pair of surfaces that is closer to the first electrode support means constituting a second clamping surface;
• a plurality of spacer members made of electrically non-conductive material, each spacer member including a first portion disposed in the first slot means and abutting the first clamping surface and a second portion disposed in the second slot means and abutting the second clamping surface for maintaining a distance in the direction of the longitudinal axis between the first and second clamping surfaces substantially constant and allowing movement between the respective support means in a direction transverse to the longitudinal axis due to differential thermal expansion.