While the forward power values drift a lot for cavities 2 and 4 in vertical separator, the DMES (not GMES) values are quite stable. SME says these are what count. Vertical position variations seen at start of C line in linked entry likely have another cause. Alas, the mystery remains.
Tails on lasers have been suggested as a potential cause of the different beam profiles on the synch light monitor in the injector.
Figure 1 before any work, Figure 2 prior slit positions.
Look at laser spots on chopper viewer to determine if there is a tail on a laser:
Figure 4: A laser with Prebuncher off
Figure 5: B laser with Prebuncher off
Figure 6: C laser with Prebuncher off
Figure 7: D laser with Prebuncher off
Figure 8: A, B, and C with Prebuncher on.
No major laser tails evident, prebunching looks fine from a quick glance.
Two tasks will be done in parallel:
Check of the INJ laser phases/setup
SLinac RF Recovery
When the front end of the machine is deemed beam worthy, work will begin on the NLinac RF Recovery.
Additionally, the Hall C CW viewer camera will be replaced and the Hall C BLA cavity heating system will be investigated.