====== 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.