Describe OffProcNika2Run1Beam here.

Discussion on beams

Page last updated, FXD, CK, 2015-11-02

We measure the beam by using the middle scan of the 3-scans sequence launched with @beammap Here are the best-of on 3 sources.

Beams on Mars

Beams on Uranus

Beams on 3C84

Preliminary findings

The main beam (the Gaussian part) seem with a normal width aka 11", 17".

The quadripod holding the secondary gives clear diffraction marks as a faint cross visible in all scans.

In between, there is a large near-side lobe, especially at 2mm (but also visible at 1mm), that shows up as a rectangular pyramid-like shape at the 10% level, the origin of which is unknown. It seems to scale with wavelength. It was not so apparent in NIKA. Therefore the quality of the dichroic is not at the center of this issue.