====== Telecon 20180509 ====== Attending: Toki, Shaul, Karl, Qi Notes by : Qi === Agenda=== * Workshop Follow Up Items * Focal plane mechanical model (SH + UMN); 1/f; temperature stability; detailed cryogenic model; * Precession Speed (Kris, Jacques) * TDM/FDM noise comparisons (Karl, Roger) * Plots of ratio of FDM to TDM noise. Ratios are NEP^2 (left) and NEP (right) * {{::tdm_fdm_ratios.png?direct&600| FDM/TDM noise}} * Largest difference is NEP_tot_FDM / NEP_tot_TDM = 1.02. Or ratio of squares, (NEP_tot_FDM / NEP_tot_TDM)^2 = 1.03 === Notes === * Workshop Follow Up Items * issues of mechanical model: focal plane weight, needs to be revisited and a more realistic model in a few weeks. Heat sinks, mounts etc. * **Toki will provide PB focal plane module** * 1/f * a number of discussions need to be tighten together * temperature stability of ADR, Hannes asked to what extend spikes of T affect responsivity * we know the magnitude of T spikes; should be straightforward * we don’t have complete cryogenic model, temperature loading is **AI for Shaul and jPL** * Precession * Jacques proposed slow precession; because the scan by scan is closer together, you can make full sky; harder to make continuous map with fast precession * Kris prefers fast precesson * TDM and FDM * We have been assuming sensitivities on FDM coming up from Matt and Franky, but the baseline (physical layout) is TDM * Karl's investigation * most recent TDM number from Roger * photon and phonon calculations between Karl and Roger agree within 1%. * ratio of total NEP squared, largest 3% * basically FDM is higher by 2-3% level. * Toki: readout noise is function of bolo normal resistance; TDM ~10 ohms, FDM ~1 ohm; TDM higher because it needs to compensate high current noise * **Conclusion: same. the numbers we had from FDM are fine.**