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Plan for the NIKA2 upgrade operations (March 1st to 11th)

See also (mention here the various pages in relation with the upgrade).

Participants

(preliminary)

On site: Samuel, Alessandro, Martino, Gregory Garde (from NEEL workshop) (to be confirmed), others (Dave, Carlos, Andrea...) ?

Remotely (people who may be contacted for particular questions in their domain of expertise) : Juan ?, Nico ?, Xavier ?, others ?

Hardware & tools situation

Hardware currently in Grenoble, to transport to the telescope (early January Samuel brought to NEEL everything that was at IRAM Grenoble):

• 3x 1 mm Arrays new design + spares
  

• Dichroic #1 with new Cu mount + Al+SS rings
  

• 1x AR pyramids machined array-side lens
  

• New "funny shape" extra optics baffle shield
  

• 5x nex IR filters
  

Already at the telescope (checked by Samuel during Jan 14-21 pool):

• 2x AR pyramids machined array-side lenses
  

• NIKA2 operation tool boxes
  

• Super-insulator spare roll
  

• PIMP with its mount, electronic gray box, and Raspberry control unit
  

Overall schedule

• Feb 25th - March 3rd: warm up NIKA2
• NIKA2 will be already warm on 2025/03/04
• March 4th - 11th: NIKA2 hardware upgrade

  • Remove NIKA2 Nose (entrance window, temperature screen behind, M7 & M8 mirrors unit).

  • Slide all cryostat main body screens to the position were the nose was to access the 100 mK mount (aka "Robot Dog") on which all cold elements are mounted (dichroic, lenses, arrays...). Be extra careful with super insulator.
  • Change 1mm arrays
  • Change of cryo lenses
  • Change dichroic
  • Slide all cryostat main body screens back in place
  • Put back the M7-M8 unit, take care of the long tie rods in order to get the best possible alignment of the cryostat optics (important not only to get the optical axis of the whole system aligned with the center of the arrays so that without Nasmyth correction the image of the point source is at the center of the arrays, but more importantly to get the pupils well aligned so that the illumination of M1 from the cryostat optics is well centered, otherwise we would pickup some warm spillover from the background behind the telescope, degrading the signal to noise (sensitivity) and the beam shape quality).
  • While putting back the nose screen one by one, change IR-blocking filters mounted on them
• March 11th - 17th: NIKA2 cooling down (maybe start already on the 9th if we are as efficient as we hope for the preceding operations)

• Once cool down has been started: check the optical alignment using the elevation axis lasers, and possibly the cryostat laser plate to be placed on the entrance window.
  

• March 18th: Once the cryostat is cold, that KID traces can be displayed on the acquisition software GUI, and that the telescope can point a blank sky in good atmosphere conditions perform a radio alignment (has to be done by the team on site during the Mar 18th-25th week; see the re-commissioning preparation page, which contain a detailed description of the radio alignment procedure)
  

For more details on the optical and radio alignments with NIKA2 check the following link: History of optical and_radio alignments of NIKA2; this document (which is also available from the NIKA2 wiki main page) contains drawings that help understanding the procedures.

Detailed operations

Not sure it makes sense to describe all the operations the team will perform in details. This would be quite cumbersome and not necessarily super useful.