====== Telecon 20180404 ======

Attending: Kris，Brian, Toki, Tom, Jeff, Shaul, Karl, Qi

Notes by : Qi

=== Agenda===

  * SPIE Papers 
    * {{::sutinspie_pico_v8.docx|Sutin Abstract}}
    * {{::kyoung_abstract_pico_spie_2018_v2.doc|Young Abstract}}
  * TeamX
    * {{::finalfocalplane_20180404.pptx|Final Focal Plane configuration}} 
    * {{::banddefinitions_v3.2.xlsx|Latest noise budget V3.2}} 
  * Setting Margins
    * {{::pico_sensitivity_calculations_teamx.pptx|PICO Noise Assumptions}}
  * {{::picoscienceprogram2.pdf|Any suggestions for workshop?}} 

=== Notes ===
  * SPIE
    * in June, mostly technical
    * Apr 9, deadline for finalizing the author list and material 

  * TeamX meeting
    * 2nd Instrument meeting; Mission meeting
    * Overall cost is the the most important product
    * no significant revelation
    * Focal plane
      * converged to one configuration; most compact, proper strehl ratio for high frequency
      * the other two, we have to change the optical design, to accommodate with high frequency
      * this focal plane has largest number of detectors; the difference compared to other two is very small though.

  * Noise budget
    * V3.2: very little change from V3.1; noise 0.63 uK arcmin before, now 0.61 uK arcmin
    * compare values with CORE and LiteBird calculation, single detector
    * we are using two independent codes to calculate. Karl at UMN; Roger at JPL. Agree within 5%, slightly difference. Reasonable confidence. 
    * various assumptions
      * to what extend our assumptions agree with other experiments
      * in some bands, noise lower than LIteBird, some bands higher than LiteBird.
      * everything seems consistent, no major change
      * Psat, safety factor of 2, we haven chosen a factor of 2, it’s used by JPL folks, also by SPIDER AND KECK. We thought it’s reasonable.
      * Quantitative calculations will be done by next week: what T of elements (mirros) could bring us to a factor of 2
      * Efficiency
        * It varies between the bands
        * Detector: lenselet + antenna + bolo, 70%
        * Edge Taper: center 10 db, lower band and higher band have different values; low, center, high: 70%, 90%, 99%.
        * End to end, 50-70%
        * Optical efficiency can mess up the estimate on safety factor
      * Emissivity
        * We are using measured emissivity from Planck. We already know, for highest bands, we may need to change to be more conservative

  * Margins
    * Space Mission, “current best estimate”, e.g. 100% yield; we are not likely to do better than 0.61 uK arkmin
    * What margin is the judge, successful or not.
    * Two paths: 
      * 1. start with assumptions 
        * each one assumption
        * "worst case"
      * 2. We can propagate backs from sigma_r 2*10^-5. 
      * 3. maybe a 3rd one, some factors on NET. 
      * Kris: instrument is one thing, how to get data to science is another
      * Raphael used mapping speed, assuming delensing on our own resolution. 1*10^-4 is the limit that Shaul said in AAS, which has margins from calculated value 2*10^-5.
        * It's not a trivial calculation
    * LiteBird 
      * does have margins
      * "large sections", different categories, based on what's typically achieved in lab and by ground experiments
      * quote r with margin in it
      * nominal performance and worst performance. Give both to science team. Worst case did not give too much science. Lately, increase number of detectors to improve “worst case”
    * Shaul is going to check with Planck team

  * Workshop
    * suggestions:
      * Kris: 1) without modulator 2) arguments on margins