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Plan for the NIKA2 re-commissioning, after the March 2025 upgrade

See also the minutes of the 2025/01/24 meeting dedicated to the re-commissioning.

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).

Overall list of operations (see detailed list below)

• 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)
• 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 will know if we need/want to re-open the cryostat to adjust the relative position of the arrays (along the z axis).

  1. the re-opening will happen (very likely).
     The re-opening is already scheduled for March 30th (Sunday).
     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
     On March 30th (Sunday) @ 10:30 the 2nd hardware intervention will begin and will take 2 days (until Tuesday morning). 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.
     

     B. 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.