beam alignment for high currents


Automated beam alignment for high exposure currents

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When using exposure currents > 100 nA, we often find that the gun must be realigned with

pg adj beam align

followed by

pg arc save beam whatever

Now you can do this automatically (for cjob jobs) by making copy of aba_after_beamrestore in a likely place such as /home/pg/bin, then adding the line

export CJ_BEAMALIGN="/home/pg/bin/aba_after_beamrestore"

to the file /home/pg/pg_local. This script contains local symbols, which are set upon logging in.

Edit the file /home/pg/bin/aba_after_beamrestore, setting

current_threshold=90

This forces the exposure job to run "pg adj beam align" before running "pg adj ebpg", for any current over 90 nA.

It is also common to save aba_after_beamrestore in the folder /home/pg/jobs.

Find a copy of aba_after_beamrestore (which is a small bash script) by asking your local Raith support person, or find it on your own ebpg with the command

locate aba_after_beamrestore

or

cd

find . -name aba_after_beamrestore

This does not eliminate the need for beam archive maintenance. You should still update the beam files once a week.



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