GE ArcamEBM Spectra H, Operation Manual

Page: 61 / 142

6
Hardware
Overview
6 6..6 6..2 2 T To op p C Co ollu um mn n
1. Grid cup holder
2. Cathode
3. Isolator
4. Oil ventilation cap
5. Corona ring
6. Flat blade connectors
7. Grid cup
The top column holds the cathode from which the
electrons are emitted. The cathode is made of a
crystal material (LaB6) and in optimal conditions it
has an estimated life time of 8
80 00 0 h ho ou urrss (emitting
time).
A current passed through a pair of contactor pins
to the cathode, heats up the cathode to the correct
operating temperature. The cathode is mounted in
a grid cup which acts as a throttle for the electron
beam. The grid cup is positioned in the grid cup
holder which is fitted and secured to the top column
with a bayonet locking ring.
The upper part and the inside of the isolator are
filled with silicone oil for isolation and heat
conductivity.
When removing the top column from the machine,
take care not to scratch the isolator, especially
against metals, as this increases the risk for arc
trips.
02 OM-710430 en-GB 57