Telecon 20180425

Attending: Bill, Hannes, Shaul, Karl, Qi

Notes by : Qi

• Workshop next week
• Comparing NETS: PICO, CORE, LiteBIRD
  • Noise comparison and margins slides

• 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.