Further decisions about next interventions etc.
== Minutes of 2025/04/11 meeting ==
The next intervention, aimed at changing the Ar2 Box C cold amplifier, will be on 3-4 June 2025. The change will happen on June 3rd (Tuesday, 8 a.m. to 8 p.m., during extended maintenance. The team will stay at the telesscope until the next day, to be ready in case something needs to be done also on June 4th.
It is discussed if a change of Ar3 could be foreseen (Box S, i.e. line 7, is currently noisier). There is another Ar3 available, actually better performing, but line 7 is completely dead. The one installed was originally labeled as "spare". There exist yet a third, with all lines working, built on a different mask, but it seems to be more sebsitive to magnetic fields, therefore was excluded fom NIKA2.
Alessandro discussed with Xavier in the past days. As a matter of fact there is always one 1,2 mm araay dominating the sensitivity. In the current case it is Ar1. The other array (Ar3) gives a small contrinution. For example if the NEFD of Ar1,3 are 15 and 20, then the Ar1+3 result is 12.5 (if pure Gaussian noise). Alessandro proposes that it could be scientifically more interesting to have a third band in place of the Ar3. It must be at high frequencies, because of the dichroic. Possibilities are a 350 GHz band (unique in the World, but with difficulties in weather condidtions and not clear if compatible with the current corrugated lenses) and a 220 GHz band (zero level of the SZ effect). Very tempting. This possibility will be discussed further in the future months. At the moment, it goes beyond the aim of the next intervention.