|Compound anodes are used where there is
a requirement for a high thermal capacity.
typically have a target area of rhenium tungsten alloy backed by
molybdenum and or graphite, the tungsten rhenium alloy resists
surface damage and "crazing" better than a pure tungsten surface,
the molybdenum and or graphite and molybdenum has a higher heat
capacity than a purely tungsten anode.
The greater the volume of metal the higher the heat capacity,
molybdenum has half the weight of tungsten and graphite one tenth
the weight so a greater mass can be used with no increase in weight
and its associated problems for rotation, construction etc.
c/o Phillips Medical