Go to the U of M home page
School of Physics & Astronomy
Probe Mission Study Wiki

User Tools

Trace:
beams_and_cl_1

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revisionPrevious revision
Next revision		Previous revision
beams_and_cl_1 [2018/07/09 11:17] – hivonbeams_and_cl_1 [2018/07/16 09:25] (current) – hivon
Line 1: Line 1:
 ====== Beams and C(l) ====== ====== Beams and C(l) ======
  
- --- //[[hivon@iap.fr|Eric Hivon]] 2018/07/02 11:37//+ --- //[[hivon@iap.fr|Eric Hivon]] 2018/07/16 09:09// 
 + 
 +[[systematicswg|Back to Systematics WG]]
    
 +=== 2018/07/16 ===
 +The beam computed at 150GHz, at a location offset by 10cm in the X (=co-scan) direction is now also available, on top of the central beam and Y=10cm beams generated earlier this month.\\
 +{{:systematicswg:maps_x10cm_feed_150ghz.png?direct&500}}
 +
 +Two different effects are now visible on the power spectra:
 +  * an overall rotation of the polarization by 1.74 deg, showing up as a strong EE to BB leakage when the full IQU beam is used instead of assuming a copolar beam (something we did **not** see in the (X,Y)=(0,0) and (0,10cm) cases)
 +  * the ell-dependent leakage from EE to BB seen previously is now larger than before.
 +
 +{{:systematicswg:w_qp_pico150_cxy_v1_picobeams.png?direct&500}}
 +{{:systematicswg:w_qp_pico150_cxy_pol_v1_picobeams.png?direct&500}}
 +
 +=== 2018/07/13 ===
 +Same exercise as on July 02, this time considering a beam at 150GHz located 10cm in the Y (=cross-scan) direction from the focal plane center (in a focal plane of 45cm in diameter).\\
 +We see this time a much larger contamination of BB, which looks like an ell-increasing leakage from EE to BB, probably due to the m=4 components (=square-like shape) of the beam map.
 +As for the central beam, the pure copolar and full IQU beam models return the same power spectra.
 +
 +{{:systematicswg:maps_y10cm_feed_150ghz.png?direct&500}}
 +
 +{{:systematicswg:w_qp_pico150_cxy_v1_picobeams_old.png?direct&500}}
 +
 === 2018/07/02 === === 2018/07/02 ===
 First GRASP simulations by Karl Young of PICO main beam responses at 150GHz at the center of focal plane, for 2 orthogonal detectors. First GRASP simulations by Karl Young of PICO main beam responses at 150GHz at the center of focal plane, for 2 orthogonal detectors.
Line 9: Line 31:
 and the ratios of U/I about 1.e-4 for both beams, meaning that the beams are very much co-polar, with very little spurious rotation (~<0.5 arcmin).\\ and the ratios of U/I about 1.e-4 for both beams, meaning that the beams are very much co-polar, with very little spurious rotation (~<0.5 arcmin).\\
 {{:systematicswg:maps_center_feed_150ghz_crop.png?direct&500}} {{:systematicswg:maps_center_feed_150ghz_crop.png?direct&500}}
 +
 +
  
 The same exercise would have to be repeated at a more representative position (ie, off-axis) where systematics (=elongation of beam and rotation of polarization) could be larger. The same exercise would have to be repeated at a more representative position (ie, off-axis) where systematics (=elongation of beam and rotation of polarization) could be larger.
beams_and_cl_1.1531153033.txt.gz · Last modified: 2018/07/09 11:17 by hivon

Page Tools