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User name brads
Log entry time 15:29:39 on November 04, 2008
Entry number 246672
This entry is a followup to: 246638
Followups:
keyword=Damaged target ladderWhen Joe opened the target enclosure around 11am this morning he found that the optics foil platform had been badly damaged by beam.
The photos were taken looking downstream from the beam-right side. You can see the tilted BeO foil at the left edge of the image.
A few items of note. The damage is worst on the downstream end (2nd figure). There is a burn through(?) boil marks on the BeO foil clip (3rd image).
The 4th image is the ladder CAD drawing (beam comes in from the right side of that figure, vs. the left side for the photos).
The ladder was in fine shape Friday night (visually confirmed then), so the damage occurred sometime on Sat, Sun, or Mon.
We looking at the archive data (BPMs vs. radiation levels, etc) to try and work out when this happened. The obvious culprit was during or after the Moeller set-up or restore and Sunday. However, the target ladder was in the no-target position (which is below the optics-foil platform), so the geometry isn't right.
We also don't understand why the MPS ion chambers didn't trip
Figure 1
Figure 2
Figure 3
Figure 4
