====== Telecon 20180228 ======

Attending: Bill, Tom, Kris, Hannes, Shaul, Karl, Qi

Notes by : Qi\\

=== Agenda===

  * Telescope and Instrument I+T (Tomo and Bill)
    * {{::20171212_picoi_t_v002.pdf|Tomo's slides}}
    * {{::plancki_t_jones_20171212.pdf|Receiver, Bill Jones}}
    * {{::iandt.pdf|I&T, PICO specific, Bill}}
  * Planck decontamination, cooling, and in-orbit checkout
  * Focal Plane configuration + ADR location + GRASP update (Karl)
    *  {{::focalplane_update_20180214.pdf|Focal plane slides}}
    * Adjusted system to alpha = 30, beta = 65. 
      * ADR position image:{{::180222_pico_beta65deg_karl_edits_adr.jpg?100|}}
    * GRASP quick update.  Slides just in case: {{::grasp_status_20180228.pdf|grasp_status}}

=== Notes ===

  * **Planck decontamination, cooling, and in-orbit checkout**
    * Someone needed to write ~ 1 paragraph.  Charles Lawrence suggested.
    * From Bill:
    * CPV (commissioning and performance verification) at L2
      * Telemetry checkout, cryogenic check, normal receiver operation etc.
      * For PICO, the best mode needs to be decided; spinning or spinning + precession; we have to spin to stabilize. Different spin rate is something interesting.
    * baking primary during launch to remove water not part of CPV
    * Passively cool, during the flight to L2

  * **Telescope and Instrument I+T (Bill)**: 
    * **Receiver**
      * Planck, did not include a lot of stuff prior to 2005
      * overview in page 1
      * some periods below:
        * Sep, 2005
          * Cryogenic chain, delivered and tested
        * Mar, 2006
          * HFI focal plane integration, 2 K bath, 100 mK, less than a week of testing; primary goal, show cryogenic works; gross noise check
        * May,2006
          * cryogenic, photometry, cooling down to 40 K, measuring surface separation
        * July,2006
          * same run as above, to do calibration, 20 day period, not fully integrated system, 2K to 100 mK, nothing at room T
          * Much longer time is better, 20 days is really risky
        * may,2008
          * final cool down, only time of fully integrated test
          * not designed to do any useful testing, cold load in front of focal plane, T is not stable, so no noise testing
        * may 2009
          * launch
     * **I&T, PICO specific**
      * counting back from launch, overview
        * T-4 years: devices level detectors 
        * T-3years: proving sub-k cryogenics, maybe spectroscopy and noise testing; 
          * the sooner you get integration tests, the better; example: problem related to wiring, you won’t know until you get the full integration
          * Planck did not have HFI+LFI fully test; 100 mK, 4K, more natural to sepaerate
          * Cryogenic photogrammetry of telescope and truss, very important for Planck
        * T-2 years: entire cooling chain
        * T-1years: require a proper chamber
      * Details:
        * T-3 years:
          * full focal plane, not the entire cooling chain
          * due to warm primary, be careful of how to mimic background operational conditions at L2
          * 3 mK fluctuation on 3K, heater, pump helium back; 10% percent level; as if we are observing CMB, for non-linearity etc.
          * no mirrors, find the right chamber, ~meter level, time being cold should not be less than 1 month
          * Polarimetric calibration ● Spectroscopic calibration
          * two runs because of some expectation of something not working
          * Planck never measured Spectroscopic with mirrors
          * Planck Polarimetric, used those obtained during device level testing; it’s tricky to do it with fully integrated system. Very difficult measurements
          * Cryogenic photogrammetry of telescope and truss [Large 300-40K chamber, 1 mo], may have to do mirrors separately for PICO, 30K, 4K
        * T-1 years:
          * cool the whole thing down, long run
          * Because of TES, optical loading, to see Psat
          * If we convince ourselves that we can do Polarimetric calibration ● Spectroscopic calibration on the whole system, we should
          * Shaul: depending on the size of chamber
          * Bill: do the math, and believe device level testings
          * Planck was lucky, given the limited time of fully integration testing.
          * Shaul: polarization modulation efficiency, one would calculate well based on the testings without mirrors.
          * Bill: angular calibration, independent may be demanding.
          * constrained bandpass mismatch, using data itself. It’s a big question to reach r<10^-4.
          * 2 month is the tight. sort of Planck schedule. better to add 1 month to do testing, not sure the cost.
          * in flight correction of HFI, the challenge is it’s difficult to do spectroscopy tests on the whole, which are in fact dependent on the whole system.
        * cost, driver, 3 level of testing set ups
          * modest, device, institutions
          * large, full focal plane, calibration equatment needed, time needed
          * 3rd, big chamber, fully integrated, time and calibration we want to test.
          * Timing is likely to drive the cost