Beams LFI
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.
For the beam we consider these three regions:
- main beam
- is the portion of the pattern that extends up to 1.9, 1.3, and 0.9 degrees from the beam center at 30, 44, and 70 GHz, respectively.
- near sidelobes
- is the pattern contained between the main beam angular limit and 5 degrees from the beam center (this is often called intermediate beam).
- far sidelobes
- is the pattern at angular regions more than 5 degrees from the beam center.
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]
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(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.