Subject: Shutdown raith SNF 2004-08-16 20:35:39: Raith shutdown
From: cwhicks@snf.stanford.edu
Date: Mon, 16 Aug 2004 20:35:40 -0700

We were unable to get an SEM image on the LEO screen. All we saw was some stripy digital
garbage at the top of the screen, and the rest of the image was entirely black, regardless
of the brightness/contrast settings or scan speed. We were also unable to get any image
on the RAITH150 screen. Restarting the LEO computer had no effect. It appears that an
imaging board is broken.
We had been attempting to write at 30 kV. We managed to increase the gun voltage to
27 kV. When we tried to increase it to 28 kV we tripped the EHT; we don't know if this
is what caused the imaging malfunction.