monitor evolution of new charge trap in z1

[sybenzvi]

@julienguy has noted the development of a new charge trap in z1b during the past two weeks. The trap's effect is visible in differences in QA plots from 2024-12-01 and 2024-12-12. See also the relevant discussion in #instops.

Note that z1, which is a replacement CCD, is currently read out in 4-amp mode. This ticket is a reminder to watch for effects on redshifts from this device as part of daily QA.

[araichoor]

reminding this ticket, as it looks like the effect is getting stronger, and now maybe starts to impact redshift quality.

here are the plots for 20241229:

• ctedetrow:

(here s a compilation for all Dec. 2024 nights: https://data.desi.lbl.gov/desi/users/raichoor/tmpdir/ctedetrowbyrow-202412-z1.pdf)

• skyzfiber:

• per-petal success rate:

[sybenzvi]

Comment: Julien has modeled the trap in software and the success rates in P1 seem to be pretty good since the start of last weekend (2025-01-03).