Attending: Brian,

Agenda:

• optical system + noise model + focal plane options (Young, Wen)
  • 1.4 m Open Dragone Options
  • 1.2 m Crossed Dragone
• TM rates for large/small aperture systems (??)
• Scan angles
• Scan angles + full sky scan simulations + integration with systematics (Gorski, Delabrouille, + all)

Notes:

Open Dragone: optical system + noise model + focal plane options (Young)

• Size of pixel defined on lowest or middle frequency band.
  • middle band, smaller pixel, higher sensitivity
  • 10 db edge taper + middle band size, overall the best in terms of mapping speed
  • edge taper is at 4K stop

• For Open Dragone, the DLFOV is small. The outer range on focal plane is not usable for high frequency, thus it’s hard to trade low -frequency detectors for more high-frequency detectors.
  • We don’t know what we need for low frequency, it depends on the synchrotron structures.

• Open Dragone Optics
  • V3.D: focal plane further from stop, linearly 10% more focal plane compared to base line
  • looks good, has room for mechanical works
  • Karl is working on coma correction on this telescope, and hopefully we will have larger DLFOV (AI)
  • V4: 10% less DLFOV compared to baseline
  • sensitivity calculation uses edge taper defined as lowest band, can be done using middle band

Large-aperture Cross Dragone (Wen)

• Why 50cm? De-scoped, cost, with spectrometer

• Cross Dragone have large DLFOV if not limited by vignetting (blockage, mirror sizes etc) as current case
  • unlike Open Dragone case, we can trade detectors at low frequency for high-frequency detectors more easily
  • ~ 3K detectors (Open) VS ~ 5K detectors (Cross)
  • F number: 1.5 (Open) VS 2.5 (Cross)
  • more detectors + larger F#, means Cross Dragone has larger focal plane

• We have filled the matrix of telescope categories

Scan (Kris)

• Simulation
• use WMAP Q/U map in V band; alpha = 22 deg, beta = 73 deg, is close to WMAP
• fast spin + different precession (fast, slow, very slow)
• slower precession, more non-smooth features, higher resolution needed
• LiteBird & Core use same convention of alpha and beta, Kris will change his definition
• The simulations are the average over 1 year
• simulating over other different periods will be very useful, give more opportunities to look into the scanning
• Kris will do two-week simulation (AI)

Scanning strategy

• Julian: 6 + 1 parameters; precession angle alpha, spin angle beta, 3 rotation rates (spin, precession, HWP), radius of L2 orbit + moon light
• Jacques will lead to make tables in wiki (AI)
• Brian: there may not be many options of the L2 orbits
  • there could be, we need more information input from project
• Amy told Shaul that we will probably have a ??? antenna for tele-communication; fly wheels
• Kris: demonstration is also important
• 20s (3 rpm) is fast, Kris do 1 rpm (AI)
• Shaul’s comments on this parameters study: 1) optimization of parameters; 2) systematics given parameters
• When mapping + noise correlation? As soon as we have the tables from Jacques, we will have a range of parameters.
• Hardware table, Shaul (AI)