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imagerteleconnotes20180516 [2018/05/16 12:35] – created hananyimagerteleconnotes20180516 [2018/05/16 15:49] (current) – wenxx181
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 ====== Telecon 20180516 ====== ====== Telecon 20180516 ======
  
-Attending: +Attending: Brian, Tom, Kris, Hannes, Jacque, Shaul, Karl, Qi,  
  
 Notes by : Qi Notes by : Qi
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   * Precession Period (Kris, Jacques)   * Precession Period (Kris, Jacques)
 +    * 10 hour precession period: {{:systematicswg:telecons:2018-05-14:orth_nobs_tprec10hrs_190_days.png?25|}} 
 +    * 48 hour precession period: {{:systematicswg:telecons:2018-05-14:orth_nobs_tprec48hrs_190_days.png?25|}}
 +    * {{::nobs_maps.pdf|More Slides}}
 +  *  {{::sensitivity_vs_frequency_20180516.pdf|Noise/Bands Figure}}
 +  * Noise Requirements vs Best Case Estimate (BCE)
 +    * Proposal: Req = BCE*rt(2)/0.9, independent of frequency
 +    * rt(2) because "Planck achieved noise within ~20% of BCE" (to be checked) 
 +    * 0.9 because the cost models assume 90% yield
 +    * first factor is applied on individual detectors, second factor on the array. 
 +
 +===Notes===
 +  * Precession Period (Kris)
 +    * Shaul: we've debating whether fast or slow precession; Jacques's argument was too fast precessions give large gaps
 +    * high-resolution, 1.6 arcmin simulations, single detector
 +    * 10 hours vs 48 hours; 2,4,5,..., 365 days of scanning
 +    * blue (or gray on right side) is either 0 or just a few hits; yellow is a few hundred
 +    * short-time plots show difference, but long-time show less difference
 +    * Kris argues that either option is good at some locations; we need to specify science goals before we really answer this question. Also, since we are using action-wheels, we can fairly easily adjust precession in space. This is different from Planck. Planck did have some big gaps.
 +    * Jacque argues that we need to compare gap size with beam size. 48 hours comes from CORE study, which has 2-min spin rate and 96-hour precession.
 +    * conclusion: the report should probably say “there are a range of considerations, for either 10 or 48 hours”
 +    * Shaul: the fly-wheel will be able to do the change of precession; slow-motion can also be done.
 +
 +  * Noise Requirements vs Best Case Estimate (BCE)
 +    * Best case estimate: not everything is most optimistic, just reasonable.
 +    * Shaul proposed BEC/sqrt(2)*0.9
 +      * root 2 is coming from Planck, which had achieved within 20% BCE.
 +      * 0.9 is 90% yield of pixels; BCE is optimistic on 100%-yield assumption
 +      * This number is for feedback loop to science teams.
 +      * Jacques: CORE did something similar, no major impacts on science
 +
   * Noise/Bands Figure   * Noise/Bands Figure
-  * Noise Requirements vs Best Case Estimate+    * goal: a standard visual 
 +    * needs to clarify things, needs suggestions 
 + 
 + 
imagerteleconnotes20180516.1526492134.txt.gz · Last modified: 2018/05/16 12:35 (external edit)

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