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Processing of the June 2025 NIKA2 Re-Commissioning

PIIC reduction of the 20250612s43 beam-map

SB, 2025/06/12 @18:20 LT: The beam map is scan 20250612s43. Results of a quick analysis of the beam map: the quality of the beam map (sky, telescope, focus, etc.) is unfortunately not good enough for making new (preliminary) Ar1 and Ar3 DAFs. Below you see the classic FOV beam-map figure. Ar3 is much worse than Ar1 likely because the best focus difference that affects it. Nevertheless, also Ar1 is unusable.

On the bright side: the central KID (Ar2, KC016, PIIC id 363) is definitely back! Yay!

PIIC reduction of the 20250616-18 beam-maps

During the second half of run 73, six beam maps have been taken, namely:

SB reduces them of 2025/06/24-....

Impressions:

• overall the conditions were better than during the first half of run 73 (2025/06/12), but still sub-optimal
• s51 does not seem very well focused on Ar3. As a matter of fact it is pretty decent also for Ar1.
• s181 and s179 seem to have a similar focus (both are extremely bad for Ar3)
• Ar3 seems to have problems. I don't know if it's a problem of focus or a problem of boxes noise. It might also be coincidential worse weather during the Ar3-focused scans than during the Ar2-focused ones. The feeling is that the Ar3 behaviour in run 73 is different with respect to run 72, in terms of either focus, boxes noise, or both, or else. Many Ar3 KIDs are lost even in the Ar3 best beam maps (20250617s51 and 20250618s90)
• best beam maps of run 73: Ar2 20250618s83; Ar1 20250618s83; Ar3 20250617s51 and 20250618s90.

The plots below show the best beam map for each of the three arrays. As you can see the result of Ar3 is still sub-optimal.

Therefore, when the beam maps analysis will be completed, I am going to install the following DAFs RPP for the three arrays:

• Ar2, I will use the run 68 DAFs RPP. The ref KID is 363 (PIIC numbering, see run 72 daily report for details), i.e. the one at the center, on the optical axis.
• Ar1, I will use the run 73 DAFs RPP. This is referred to the same Ar2 reference KID, hence this AR1 RPP is aligned as the Ar2
• Ar3, I will use the run 72 DAFs RPP. This is referred to the Ar2 that was missing box C, that is it was missing the central KID. Hence this Ar3 DAF RPP ill show a (big) offset with respect to Ar2 and Ar1. Whe you'll see this offset in the PIIC monitor, DO NOT PANIC. Ignore this shift, please. It is temporary and it will disappear when we have a decent beam map for Ar3, to be used to finally define new Ar3 RPPs with the same reference (central KID of Ar2).

My feeling is that the focus offset of Ar3 wrt the other reached now a critical level, provided that this is the only problem and that there are no other issues with some other optical element (the polarizer? the arrays "z" angle wrt their optical axis? else?). If confirmed, I think that this should be fixed.