imagerteleconnotes20180425 [Probe Mission Study Wiki]

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====== Telecon 20180425 ======

Attending: Bill, Hannes, Shaul, Karl, Qi

Notes by : Qi

=== Agenda===

  * [[http://pico.umn.edu/program|Workshop next week]]
  * Comparing NETS: PICO, CORE, LiteBIRD
    * {{::pico_lb_core_net_comparisons_20180424.pdf|Noise comparison and margins slides}}
    

=== Notes ===

  * link for workshop


  * Noise comparison (Karl)
    * page 2
      * left is in log scale, right is just a zoom for low frequencies
      * a few changes:
        * 4 years to 5 years, after Mission study meeting, ~900M, still 10% less than cap
        * 10% loss from low-pass filters. Planck had ~15%. There are 3-4 elements, each has ~3% loss.
      * Bandwidth, optical efficiencies and temperatures are the main factors that distinguish experiments.
      * PICO: 25% top-hat bandwidth, 70% optical efficiency (lenselet+loss+bolo)
      * Karl is going to check with Jaques if spillover was included in optical efficiency for CORE; check with Toki if he can bring more numbers here for next week's workshop
      * CORE has higher load in high-v, probably due to both warm mirrors (and warm stop)
      * LiteBird: data not very available; from 2016 paper. Small pixel size, thus large spillover leads to low efficiency.
      * Conclusion: all similar, most difference is high frequency due to mirror temperatures.
    * page 3
      * 6K is not totally hypothetical; Shaul talked with JPL engineers and it could end up at 6K.
      * temperature stability at 6K
        * Planck's 2K stage had very high emissivity, it dominated the coupling. Though the time scale was long enough that it did not affect data much.
      * Bill: 95% observing time for 5 years may be optimistic.

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