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== Beam maps analysis ==

We have a new Ar3 and we need to characterize its geometry and its flat field. To this aim, on 2026/03/24 we took two beam maps focused on Ar1 (scans 20260324s169 and 177). The idea and hope is that the focus of Ar3 is roughly the same of that of Ar1, thanks to the March 10 intervention, and these beam maps will be good for our purpose.

We reduce the beam maps during the night between 2026/03/24 and 25. <<BR>>
Ar2 is out of focus and in order to be able to reduce it, we need to relax completely the constraints on its beam size and shape. <<BR>>
Ar1 is well on focus. The best beam map is 177. The other (169) has some problems at the lower edge for unknown reasons. <<BR>>
The Ar3 focus is decent. The array is missing Box S, as already known, and also several KIDs in Boxes M, N O (supposedly).

Below here you can see the geometry of the three Arrays as derived from the average of these two beam maps.

[[attachment:ar2run80_yynn_1_0_2_beamsAvMedAll.jpg|{{attachment:ar2run80_yynn_1_0_2_beamsAvMedAll.jpg|Ar2 beam maps 169 and 177|height=400}}|target="_blank"]]
[[attachment:ar1run80_yynn_1_0_2_beamsAvMedAll.jpg|{{attachment:ar1run80_yynn_1_0_2_beamsAvMedAll.jpg|Ar1 beam maps 169 and 177|height=400}}|target="_blank"]]
[[attachment:ar3run80_yynn_1_0_2_beamsAvMedAll.jpg|{{attachment:ar3run80_yynn_1_0_2_beamsAvMedAll.jpg|Ar3 beam maps 169 and 177|height=400}}|target="_blank"]]

== Study of the Ar1 and Ar2 beams at different focus values ==

On 2026/03/25, we carried out a series of calib_1scan with different focus values, starting from the Ar1 optimal focus to the Ar2 optimal focus, in steps of 0.2 mm. The aim was to study the change of MB flux (because the CAL is based on main beams), % of flux in the side lobes of the beam, and FWHM of the minor/major axes of the beam, as a function of focus (distance from the optimal position). Below here you find a table that summarizes our measurements and a series of plots produced by the PIIC monitors for Ar1 and Ar2.
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 |||||||||||||||||||||||||| Study of side lobes (TP, point-like) ||
 |||||||||| General |||||||| Ar1 |||||||||| Ar2 ||
 || Scan nr || El. [deg] || Target || Z Focus [mm] || Notes || MB flux [mJy] || Side lobes % || FWHM min [arcsec] || FWHM max [arcsec] || MB flux [mJy] || Side lobes % || FWHM min [arcsec] || FWHM max [arcsec] ||
 || 243 || 48.8 || 3C273 || 1.35 || Ar1 focus || 4.85 || 7.4% || 11.40 || 11.86 || 6.96 || 8.5% || 17.72 || 20.47 ||
 || 245 || 50.1 || 3C273 || 1.15 || Ar1-0.2 mm || 4.32 || 9.5% || 11.43 || 12.84 || 7.19 || 7.7% || 17.54 || 19.49 ||
 || 247 || 51.8 || 3C273 || 0.95 || Ar1-0.4 mm || 4.07 || 11.2% || 11.61 || 13.06 || 7.21 || 7.8% || 17.24 || 19.60 ||
 || 249 || 52.9 || 3C273 || 0.75 || Ar1-0.6 mm || 3.77 || 16.0% || 12.44 || 15.67 || 7.51 || 7.2% || 17.19 || 18.84 ||
 || 251 || 53.7 || 3C273 || 0.55 || Ar1-0.8 mm || 3.62 || 19.8% || 14.78 || 21.86 || 7.47 || 7.3% || 17.34 || 18.56 ||
 || 253 || 54.3 || 3C273 || 0.35 || +/- Ar2 focus || 3.64 || 28.1% || 17.40 || 29.17 || 7.34 || 8.0% || 17.59 || 18.59 ||
 || || || || || || || || || || || || || ||
 || || || || || || || || || || || || || ||
 |||||||||||||||||||||||||| NOTE: the focus values listed here do already include the -0.2 adjustment for the curved focal surfaces ||

Back to the NIKA2 Run 80 main page

Run80 data processing

Here we include the preliminary data reduction results of the re-commissioning NIKA2 run 80, as obtained at the telescope during this week (2026/03/24-31).

Focus difference between the three arrays

As of 2026/03/25 @01:25 UT.
The focus difference Ar1-Ar2 is roughly +1.00 mm.
The focus difference Ar3-Ar1 is roughly -0.05 mm.

  • Focus sequences

    Scan nr

    Target

    Ar2

    Ar1

    Ar3

    Polarized?

    Notes

    20260324s153-157

    Uranus

    0.27

    1.25

    1.2

    no

    Started at 1.0 mm; tadadada; Ar2 good fit; Ar1 and Ar3 fit is marginal

    158-162

    Uranus

    out

    1.3

    1.25

    no

    Started at 1.5 mm; Ar1 perfect fit; Ar2 out of range

    163-167

    Uranus

    0.28

    out

    out

    no

    Started at 0.5 mm; Ar2 perfect fit; Ar1 out of range

    171-175

    Uranus

    out

    1.22

    1.18

    no

    started at 1.5 mm; Ar1 perfect fit; Ar2 out of range

    206-210

    0851+202

    out

    1.36

    1.31

    no

    Started at 1.4 mm; Ar1 and Ar3 perfect fit; Ar2 out of range

Ar2 focus, scans 153-157 Ar1 focus, scans 153-157 Ar3 focus, scans 153-157

Ar2 focus, scans 163-167 Ar1 focus, scans 158-162 Ar3 focus, scans 158-162

Ar1 focus, scans 206-210 Ar3 focus, scans 206-210

Beam maps analysis

We have a new Ar3 and we need to characterize its geometry and its flat field. To this aim, on 2026/03/24 we took two beam maps focused on Ar1 (scans 20260324s169 and 177). The idea and hope is that the focus of Ar3 is roughly the same of that of Ar1, thanks to the March 10 intervention, and these beam maps will be good for our purpose.

We reduce the beam maps during the night between 2026/03/24 and 25.
Ar2 is out of focus and in order to be able to reduce it, we need to relax completely the constraints on its beam size and shape.
Ar1 is well on focus. The best beam map is 177. The other (169) has some problems at the lower edge for unknown reasons.
The Ar3 focus is decent. The array is missing Box S, as already known, and also several KIDs in Boxes M, N O (supposedly).

Below here you can see the geometry of the three Arrays as derived from the average of these two beam maps.

Ar2 beam maps 169 and 177 Ar1 beam maps 169 and 177 Ar3 beam maps 169 and 177

Study of the Ar1 and Ar2 beams at different focus values

On 2026/03/25, we carried out a series of calib_1scan with different focus values, starting from the Ar1 optimal focus to the Ar2 optimal focus, in steps of 0.2 mm. The aim was to study the change of MB flux (because the CAL is based on main beams), % of flux in the side lobes of the beam, and FWHM of the minor/major axes of the beam, as a function of focus (distance from the optimal position). Below here you find a table that summarizes our measurements and a series of plots produced by the PIIC monitors for Ar1 and Ar2.

  • Study of side lobes (TP, point-like)

    General

    Ar1

    Ar2

    Scan nr

    El. [deg]

    Target

    Z Focus [mm]

    Notes

    MB flux [mJy]

    Side lobes %

    FWHM min [arcsec]

    FWHM max [arcsec]

    MB flux [mJy]

    Side lobes %

    FWHM min [arcsec]

    FWHM max [arcsec]

    243

    48.8

    3C273

    1.35

    Ar1 focus

    4.85

    7.4%

    11.40

    11.86

    6.96

    8.5%

    17.72

    20.47

    245

    50.1

    3C273

    1.15

    Ar1-0.2 mm

    4.32

    9.5%

    11.43

    12.84

    7.19

    7.7%

    17.54

    19.49

    247

    51.8

    3C273

    0.95

    Ar1-0.4 mm

    4.07

    11.2%

    11.61

    13.06

    7.21

    7.8%

    17.24

    19.60

    249

    52.9

    3C273

    0.75

    Ar1-0.6 mm

    3.77

    16.0%

    12.44

    15.67

    7.51

    7.2%

    17.19

    18.84

    251

    53.7

    3C273

    0.55

    Ar1-0.8 mm

    3.62

    19.8%

    14.78

    21.86

    7.47

    7.3%

    17.34

    18.56

    253

    54.3

    3C273

    0.35

    +/- Ar2 focus

    3.64

    28.1%

    17.40

    29.17

    7.34

    8.0%

    17.59

    18.59

    NOTE: the focus values listed here do already include the -0.2 adjustment for the curved focal surfaces

Run80processing (last edited 2026-08-30 17:59:13 by imyserlis)