Julian, Sheila, Vicky, Camilla. After today's alog 75677 ZM4 PSAMs offloading. WP11666
Started with ZM4 sliders at Pit -362, Yaw -273. Our beam off the OPOS was good, centered on both HAM7 QPDs with nsum 150 to 160.
The beam was off mainly in yaw, centered on irises by moving sliders to Pit -521, Yaw -1213. This was with PSAMS at 200V. There is still loads of range on the sliders, DAC counts up to 27,000 out of 500,000.
We watched the beam and ramped PSAMS from 200V to 0V over 30s, the beam may have moved slightly higher.
Leaving both ZM4 and ZM5 PSAMS at 0V for tomorrows work.
ZM4 has a 16bit DAC and hence we will need to mechanically relieve it in both pitch and yaw.
For the ZM4-5-6 alignment check after offloading PSAMS on ZM4 (75677) and ZM5 (75709) -- reminder that as-is, ZM6 is almost railed. Ideally none of ZM 4-5-6 are saturating.
So, before mechanically offloading ZM 4-5, can also check alignments with ZM6 sliders set ~0. For example, we brainstormed next steps like:
(i) use ZM5 sliders to center ZM4-5 alignment on HAM7 irises. SQZ beam should then naturally hit AS_C.
(ii) zero the ZM6 sliders, then use ZM4-5 sliders to recover the beam on AS_C. Then could offload if needed.