high mag problems
jwc at snf.stanford.edu
Wed Feb 25 11:50:50 PST 2004
Good Morning Raith Users:
I have put the system into 'red light' mode == SHUTDOWN.
The EHT trips that were experienced by John Cummings were unusual
events. I was very surprised to learn upon arriving today that users had
several different problems overnight. Note that we had run the system
slowly up to 20 and 30 keV without problems before releasing the system
to users yesterday.
The root of the problem: arcing events in the gun section.
The Magnification Amplifier No. 3 in the Electron Optics section (E/O)
which switches at about 13.6 kX was found to have failed during my
troubleshooting this morning. I am currently testing out the gun
section again. LEO USA and RAITH USA have been informed of the problem,
and we are trying to locate a E/O board here in America to replace the
blown board as soon as possible.
Please adjust your schedules accordingly -- likely down through Friday
Noon. I will post to this list when I have more information.
Mark Allen Topinka wrote:
>Yep, problem is still there. It happens when you go to the high-mag
>amplifiers (when you hear that click) for me it's WD=6.808mm and
>mag=11.87KX. At that mag, the image seems to stretch by like a factor of 2
>in the x direction and starts drifting. I'm going to go ahead and write
>some coarse features, but as it stands it would be harder than usual to try
>and focus/stigmate the beam on high-mag. (Note: it might still work, since
>even most high-res writing is done at 1200X max, but I wouldn't bet my
>prize wafer on it). -Mark
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