User's Manual

TES-63 Source
User manual – version 06/2021
Page 27/46
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Usually, this value is between 3 and 5W depending on the configuration.
c) Cycle between HV and pulse HF to ignite plasma
- Press the button Pulse UHF, then release the button. This will set the UHF power to its maximum
to ignite the plasma.
- Then activate the HV button and set the HV beam to 2kV. Be careful to any arc than can happen,
it is normal, but if there is too many, lower the HV setting until we lower the gas valve setpoint.
- Look at I Beam indicator, if it indicates a value > 1µA, that is the plasma and the beam are on.
- Turn off the HV.
- If the beam was on, continue the protocol, if the beam was off (I Beam still at 0 µA when HV on),
restart this cycle
d) Go down to the normal gas valve setpoint
Now the plasma is on, go down to a lower value for the gas valve set point. The value is generally about
1.75V for 0.5bar inlet pressure and a 350µm plasma aperture.
e) Ready to be used
The source is ready to be used, plasma is on, and operating points are set.
Set the beam and focus high voltages. Modify the UHF power value to adjust I Beam. Modify U Focus
to change the geometry of the beam (divergent, parallel, etc…)
The beam can be temporarily turned off and on again by deactivating and reactivating the "High
Voltage" button. This can be useful for example to move a sample or Faraday cup in the beam path.
6.5 Operating an ion beam with active current stabilization
a) Current stabilization mechanism
The program offers the possibility to actively stabilize the current drawn from the high voltage power
supply that feeds the source body. If the source is correctly operated this current is equivalent to the
beam current.
Upon activation of the current stabilization, the current is modified by manipulation of the applied UHF
power, to reach and then stay at the specified level within the specified precision.
The current stabilization mode should only be activated when the ion beam is on.