Difference between revisions of "Beams LFI"
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Each beam of the radiometer pair (Radiometer Chain Assembly - RCA) is named as LFIXXM or LFIXXS. XX is the RCA number ranging from 18 to 28; M and S are the two polarization namely main-arm and side-arm of the Orthomode transduccers <cite>#darcangelo2009b</cite>. | Each beam of the radiometer pair (Radiometer Chain Assembly - RCA) is named as LFIXXM or LFIXXS. XX is the RCA number ranging from 18 to 28; M and S are the two polarization namely main-arm and side-arm of the Orthomode transduccers <cite>#darcangelo2009b</cite>. | ||
− | [[File:fieldofview.png|500px|thumb|centre|Figure 1. A sketch of the Planck LFI field of view in the (u,v) plane is shown. The polarization direction on the sky are highlighted by the colored arrows. The M-polarization is shown in green and the S-polarization in red. | + | [[File:fieldofview.png|500px|thumb|centre|Figure 1. A sketch of the Planck LFI field of view in the (u,v) plane is shown. The polarization direction on the sky are highlighted by the colored arrows. The M-polarization is shown in green and the S-polarization in red. Main beam shapes are shown for completness and they are not representative of flight beams.]] |
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For the beam we consider these three regions: | For the beam we consider these three regions: | ||
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; near sidelobes: is the pattern contained between the main beam angular limit and 5 degrees from the beam center (this is often called <b>intermediate beam</b>). | ; near sidelobes: is the pattern contained between the main beam angular limit and 5 degrees from the beam center (this is often called <b>intermediate beam</b>). | ||
; far sidelobes: is the pattern at angular regions more than 5 degrees from the beam center. | ; far sidelobes: is the pattern at angular regions more than 5 degrees from the beam center. | ||
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== Main Beams and Focal Plane calibration == | == Main Beams and Focal Plane calibration == |
Revision as of 14:17, 25 February 2013
Contents
Wish List[edit]
list of information to be inserted in the explanatory supplements
- Description of LFI FOV.
- Description of various telescope models as reported in the beam paper.
- Format of beam data
- Definition of various coordinate frames for beams
Overview[edit]
LFI is observing the sky with 11 pairs of beams associated with the 22 pseudo-correlation radiometers. Each beam of the radiometer pair (Radiometer Chain Assembly - RCA) is named as LFIXXM or LFIXXS. XX is the RCA number ranging from 18 to 28; M and S are the two polarization namely main-arm and side-arm of the Orthomode transduccers #darcangelo2009b.
Main Beams and Focal Plane calibration[edit]
Describe the RIMO content (beam section)
The beam solid angle, Ω
, of an antenna is given by\Omega where
is the normalized power pattern and the field computed by GRASP is normalised to a total power of 4π watt, i.e.,Effective beams[edit]
TBW
Window Functions[edit]
TBW
Sidelobes[edit]
TBW
References[edit]
<biblio force=false>
</biblio>
(Planck) Low Frequency Instrument
Field-Of-View
LFI Radiometer Chain Assembly
[LFI meaning]: absolute calibration refers to the 0th order calibration for each channel, 1 single number, while the relative calibration refers to the component of the calibration that varies pointing period by pointing period.