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Plan for the NIKA2 re-commissioning (March 18th to 25th + March 30th to April 1st, 2025)

See also the minutes of the 2025/01/24 meeting dedicated to the re-commissioning (at the difference of the minutes, which describe things as they were discussed during the meeting, the test plan below, originally extracted from these minutes, may contain few differences resulting from upgrades depending on possible evolution of the hardware situation and new information since the meeting. So please refer to this test run page for the actual plan that the re-commissioning team will follow (in principle differences should be marginal).

Originally, two weeks were booked for the re-commissioning. The plan was to quickly assess the relative focus between the three arrays and decide if we need to re-open in order to move the arrays and bring them to the same focus position (as much as possible).

The re-commissioning has now been reduced to one week in march and a second week at a later time, possibly at the end of May or beginning of June. In fact we realised that warming up takes 5 days, cooling down takes ~one week, and therefore re-opening the cryostat to move the arrays would occupy more than one week and we would have had no time for the second part of the re-commissioning (after the 2nd opening).

Participants

(preliminary)

On site: Angel, Stergios, Stefano, Carsten, Juan Macias-Perez (to be confirmed)

Remotely: Nicolas (except 18/3 @ 17 and 21/3 in the evening), Xavier (20-24/3), Samuel, Alessia (18-21/3)

Brisa is warned of the chance of using EMIR if anything goes wrong with NIKA2

Overall schedule

• March 4th - 11th: NIKA2 hardware upgrade
• March 11th - 17th: NIKA2 cooling down (maybe start already on the 9th, see above)
• March 18th: start the re-commissioning of NIKA2, after cooling down

• We are going to use the use t22 account
  -> copy the current scripts into the directory PaKo/202503/

• IMPORTANT NOTE: if problems pop up during the recommissioning?
  -> re-open! (hardware people be ready)
  -> use EMIR meanwhile

• March 18: the first action is the new sweep (Martino, Alessandro, Dave)
• The second action is checking the radio alignment using the Eccosorb technic (added by SL, 30/01/2025). The following assumes radio alignment is correct (if not, either it can be compensated, or a re-opening is necessary, which means few hours to many days delay).
• We then spend one-two days for the first characterization of the arrays, aimed at determining the new kidpars (IDL pipeline). Nicolas will work with us remotely during these first phase. Details are given below.
• This process will take ~2 days, including the new kidpars/DAFs and likely also the verification of the relative focus between the arrays. It might be faster, but let's count ~2 days.

• At this stage we planned to know if we need/want to re-open the cryostat to adjust the relative position of the arrays (along the z axis). We have decided to post-pone this decision to a later time, after a thorough analysis of the data taken during this first re-commissioning week. Two cases might apply:
  

  1. The re-opening will happen (very likely). We had originally scheduled it for March 30th (Sunday), but eventually decided it was safer in terms of people travel organization to reach this stage of knowledge of the upgraded instrument situation before taking decision (reverse everything / just move arrays / no re-opening necessary: go to B.). The following assumes we don't need to reverse everything.
     For the rest of the March 18-25th week, we proceed with the first part of the re-commissioning, aimed at characterizing the new arrays and test/characterize as much as possible the upgraded NIKA2
     On March 25th (Tuesday, maintenance day) @ 10:30: start warming up NIKA2 Only if necessary (depends on the decision mentioned just above)
     On March 30th (Sunday) continue got get more re-commissioning data, possibly at the light of the processing of the preceding week data.
     At the date decided above, probably sometimes in April or early May: the 2nd hardware intervention will begin and will take 2 days. The arrays will be moved along the z-axis in order to bring them to the same focus (as much as possible)
     The 2nd half of the re-commissioning (after the 2nd intervention) will be at the end of May or beginning of June, because April is fully taken by EHT and in the first half of May not everyone will be available.
     

  2. we decide not to re-open (unlikely).
     We proceed with as many re-commissioning operations as possible, including the full characterization of the instrument, as described in the next Section below, including stage-2 operations such as a pointing session and de-focused beam-maps.

Detailed operations