Diff for "DailyReportsNika2Run5" - www.iram.es Main Wiki

Differences between revisions 3 and 7 (spanning 4 versions)

Contents

September 2016, 17 (Saturday)

Finish mounting NIKA2 back in place. Everything went fine and smoothly, without problem.
Start leak tests.
Zemax simulations done. Ray tracing figures look scary, but it's the PSF that matters:
- For the default on the 1K lens: ~1/3 of the image surface is affected (top side); extra aberrations appear in the side lobes at ~10^-2 level, the beam peak decreases by up to 6%, the encircled energy at the 1st dark ring (13dB level) decreases by up to 5% <=> the benefice of the corrugations AR effect is cancelled out for those pixels. It seems acceptable; we'll see on the sky with beam maps.
- For the default on the 2 100mK lenses: 80% of the image is affected (red cross shape); extra aberrations appear in the side lobes at ~5x10^-3 level, the beam peak decreases by up to 4.5%, the encircled energy at the 1st dark ring (~-13dB level) decreases by ~3.7% <=> a significant fraction of the benefice of the corrugations AR effect is cancelled out, but not all. It seems acceptable.

Arrival at the telescope of Samuel.
Unload truck dismount NIKA2 nose, roll NIKA2 body it in the corridor.
Dismount NIKA2 body, up to the cold stage optics.
Change the 1K lens in the corridor: remove the smooth one, place the corrugated one. See a small default that hadn't been seen before on a section of the new corrugated lens: groove ~5mm wide, ~0.1-0.3mm deep, ~5-7cm long. Probably acceptable; decide to keep the lens, Samuel will simulate the effect with Zemax.
Change the 100mK lenses in the servo room (floor below the receiver cabin). Here also a small known default on 2 of the 5 lenses: ridge ~0.5mm wide, ~0.3mm high, along 2 perpendicular diameters. Before coming Samuel estimated with a simplified simulation it was acceptable, he will simulate more accurately the default.
Change the 2mm array: replace the 1020 KIDs array with the new 616 KIDs array.
Change the dichroic.
Start mounting again everything together.

Arrival at the telescope of Johannes, then Alessandro, Martino and Aurelien with the truck.

-  ⇤ ← Revision 3 as of 2016-09-17 16:30:17 → 
  Size: 1365
  Editor: NikaBolometer
  Comment:
+   ← Revision 7 as of 2016-09-17 18:00:23 → ⇥
  Size: 2255
  Editor: NikaBolometer
  Comment:
-Deletions are marked like this.
+Additions are marked like this.
 Line 8:
+ * Zemax simulations done. Ray tracing figures look scary, but it's the PSF that matters: 
  * For the default on the 1K lens: ~1/3 of the image surface is affected (top side); extra aberrations appear in the side lobes at ~10^-2 level, the beam peak decreases by up to 6%, the encircled energy at the 1st dark ring (~-13dB level) decreases by up to 5%  <=> the benefice of the corrugations AR effect is cancelled out for those pixels. It seems acceptable; we'll see on the sky with beam maps.
  * For the default on the 2 100mK lenses: 80% of the image is affected (red cross shape); extra aberrations appear in the side lobes at ~5x10^-3 level, the beam peak decreases by up to 4.5%, the encircled energy at the 1st dark ring (~-13dB level) decreases by ~3.7% <=> a significant fraction of the benefice of the corrugations AR effect is cancelled out, but not all. It seems acceptable.
-Line 15:
+Line 18:
- * Change the 2mm array: replace the 1100 KIDs array with the new 660 KIDs array.
+ * Change the 2mm array: replace the 1020 KIDs array with the new 616 KIDs array.