Subject: Re: Comment raith 2003-08-16 20:09:50: EHT Trips and Gun settings...
From: James Conway <jwc@snf.stanford.edu>
Date: Tue, 19 Aug 2003 11:50:58 -0700
Tue, 19 Aug 2003 11:50:58 -0700
Onur and RAITH Users:

ALL USERS:
Please call me the next time you are tempted to change the gun settings.

These parameters are not to be changed by users --- EVER!
It takes several hours to a full day for all the gun parameters to
stabilize after a significant change is made to the settings.

I appreciate what you were trying to achieve but the settings will not
render a useful beam from a brightness and source spot size /divergence
of the Beam at the source standpoint. The beam I and flux per unit area
will be too low!

LEO was aware of the situation we were having with EHT I stability on
their exit last Friday. We were monitoring the gun parameters using the
gun server utility.  When the system was reset SAT. the data was lost.

 Monday,  I had LEO come in again and we readjusted the gun back to near
the factory determined settings. We also ran emission  I up and down
hoping  to reform and heal the gun tip if possible.
 This was done in an effort to improve the gun emission stability, and
to determine if the tip itself was damaged. (EHT I was wildly
fluctuating Friday and Sat. It seems to have stabilized during the last
24 hours.)  No trips were experienced overnight or this morning so the
tip now seems to be behaving and now the new EHT power supply seems to
have run itself into normal service.  We will be closely monitoring the
system through the week.

How did your ebeam writing come out?

Thank you for your support!

James Conway



Onur and RAITH Users:

ALL USERS:
Please call me the next time you are tempted to change the gun settings.
These parameters are not to be changed by users --- EVER!
It takes several hours to a full day for all the gun parameters to stabilize after a significant change is made to the settings.

I appreciate what you were trying to achieve but the settings will not render a useful beam from a brightness and source spot size /divergence of the Beam at the source standpoint. The beam I and flux per unit area will be too low!

LEO was aware of the situation we were having with EHT I stability on their exit last Friday. We were monitoring the gun parameters using the gun server utility.  When the system was reset SAT. the data was lost.

 Monday,  I had LEO come in again and we readjusted the gun back to near the factory determined settings. We also ran emission  I up and down hoping  to reform and heal the gun tip if possible.
 This was done in an effort to improve the gun emission stability, and to determine if the tip itself was damaged. (EHT I was wildly fluctuating Friday and Sat. It seems to have stabilized during the last 24 hours.)  No trips were experienced overnight or this morning so the tip now seems to be behaving and now the new EHT power supply seems to have run itself into normal service.  We will be closely monitoring the system through the week.

How did your ebeam writing come out?

Thank you for your support!

James Conway