Notes for the next re-commissioning campaign(s)

Following the results of the July 12-13th, 2025 session, and the 2025/07/16 NIKA2 meeting, here come some notes and suggestions about how to proceed with the next re-commissioning time.

Comments and impressions by SB about the last re-commissioning session:

• we still do not have DAFs/Kidpars with the central KID as reference for all three arrays. With the June 3rd intervention, Box C was recovered, therefore we can use the Ar2 DAFs/Kidpars of run 68 (the SWEEP hasn't changed). On the other hand for the new Ar1 and Ar3 we do not have yet any DAFs/Kidpars with the central KID (in Box C - Ar2) as reference because run 72 had no Box C and the beam maps of run 73 were not good enough.
• Therefore the priority of run 74 were beam maps rather than calib_1scans
• The daily report of run 74 mentions a problem with the focus of Ar1 and Ar3. this was followed up also in an emails exchange yesterday. The problem here is that the DAFs of Ar1 and Ar3 are shifted wrt those of Ar2. We need to use the Ar2 centered on the the central KID, though, because we need to produce DAFs well cenetred also for Ar1 and Ar3. This shift makes so that the source in Ar1 and Ar3 is far from the center (it's only a software shift, not a real one), and falls out of the 30 arcsec circle that is used by the PIIIC QL to "mask" the source. Consequently the data reduction rejects the KIDs that see the source, because the timelines are "too noisy" (the source is not masked).
• the daily report also mentions that the old imbfits scripts did not work. SB looked for the data but he took some time to find them because he was looking for those produced by the old make-imbf scripts. The question is whether the new make-imbf data are now free from the "slow/fast/fused traces problem" that started in February. If yes, then PIIC can process the beam maps imbf produced in this way. If not, then it can't because times are not monotonic. Miguel reports that the problem was recently fixed by OHB, therefore there should be no problem. There are still a couple of such events per day, but nothing dramatic.
• SB will then process th ebeam maps in the next days
• Jean suggests that some fix could be implemented in PIIC, in case the remaining few events per day would affect some NIKA2 scans. SB says that we should understand first if it's worth it: in order to implement a patch, he needs to find where in PIIC to do it (which takes at least one month of study of the code), then few hours of coding, and finally few days of testing. He thinks that recovering a couple of scans per day, it is not worth to work more than one month on PIIC.

  
  

Beam maps reduction by Nicolas using the IDL pipeline

• Nicolas has reduced the three beam maps with the IDL pipeline.
• scan 45 looks fine for Ar2. Ar1 is rather bad. In Ar3 most of the KIDs were rejected. SB has the feeling that this is simply due to the fact that Ar3 is completely ot of fcus when focusing on Ar2
• scan 47 looks very weird. Only a small circular patch is preserved, while the outer ring is lost. It's strange, becaue such a pattern looks line if there was an obscuration of the windown or so, and it does not even go by boxes.
• scan 78 looks OK for Ar2, decent for Ar1 (missing mainly KIDs in one box), and better than 45 for Ar3, but still rather bad.
• the feeling by SB and NP is that we will need yet another re-commissioning session to have proper beam mps for proper DAFs/Kidpars.
• Current (preliminary) estimate of focus offsets: AR2 (0mm), AR1 (+0.3 mm), AR3 (+0.6 mm).

  
  

Possible new re-commissioning sessions:

• Carsten says that few hours of NIKA2 recommissioning could be included in the next EMIR pool (August 19-26th). Therefore it is important to make so that NIKA2 will be cold during that week. Miguel will be the AoD.
• similarly there will be another EMIR pool in Spetember, but it has not been scheduled yet.

  
  

Main Goals:

• the prioriy are beam maps

• produce new final NEFDs for total power
• produce new final NEFDs for polarimetry (probably and likely in Autumn).

Observing procedure for August (by SB, double checked by Lea)

• the prioriy are beam maps, as a start.

• under the assumption that the PIIC DAFs will still be hybrid: Ar2 DAFs referred to the central KID (i.e. run 68 DAFs); Ar1 and Ar3 DAFs shifted (i.e. run 72 DAFs).
  • @nkpoint b
  • set pointing XX YY (use the Ar2 offsets)
  • @focusOTF-Z zz
  • set focus ZZ (use the Ar2 focus)
  • @nkpoint b
  • set pointing XX YY (use the Ar2 offsets)
  • @beam map 99 scans !!! this is going to be the Ar2 beam map
  • @nkpoint b
  • set pointing XX YY (use the Ar1 offsets)
  • @focusOTF-Z zz
  • set focus ZZ (use the Ar1 focus)
  • @nkpoint b

  • set pointing XX YY (use the Ar2 offsets)

  • @beam map 99 scans !!! this is going to be the Ar1 beam map
  • @nkpoint b
  • set pointing XX YY (use the Ar3 offsets)
  • @focusOTF-Z zz
  • set focus ZZ (use the Ar3 focus)
  • @nkpoint b

  • set pointing XX YY (use the Ar2 offsets)

  • @beam map 99 scans !!! this is going to be the Ar3 beam map
• then proceed with focus sequence for Ar2, Ar1 and Ar3, using the scheme as above for the beam maps
• then calib_1scan on primary and secondary calibrators
• then a deep field (5 hours on source)