Power-up Procedure
1. Let system be at 20kV 10mA until IG reading is
substantially below 100mV.
2. Keep TUBE VOLTAGE at 20kV, increase (push UP button) TUBE CURRENT
by 10mA once a time until reaching 40mA, and each time wait until
IG reading drops back to below 100mV before going to next step.
3. Do the same to gradually go to 30kV 60mA, 40kV 80mA, and finally
50kV 100mA. Again, Make sure IG reading drops below 100mV each time. If
IG reading fluctuates dramatically when powering-up, go back to the previous
setting (use DOWN button).
See can't power up
if failed.
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When system reaches this reading, you can start beam
alignment. However, please be aware of the following:
1. The time period for powering-up can vary. Usually, if vacuum
was broken (such as after filament change),
it will take much longer, sometimes even overnight at intermediate steps.
2. NEVER try to power-up fully when IG reading is greater than
125mV. Normally, the reading stays between 50 and 90mV when the system
has stabilized.
3. If for a long period (such as overnight or longer) no user plans
to collect data, set the system at 50kV 50mA. This substantially increases
filament life time.
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