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imagerteleconnotes20180228 [2018/02/28 14:01] hananyimagerteleconnotes20180228 [2018/02/28 16:27] (current) kyoung
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 ====== Telecon 20180228 ====== ====== Telecon 20180228 ======
  
-Attending:+Attending: Bill, Tom, Kris, Hannes, Shaul, Karl, Qi
  
-Notes by : \\+Notes by : Qi\\
  
 === Agenda=== === Agenda===
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     * {{::20171212_picoi_t_v002.pdf|Tomo's slides}}     * {{::20171212_picoi_t_v002.pdf|Tomo's slides}}
     * {{::plancki_t_jones_20171212.pdf|Receiver, Bill Jones}}     * {{::plancki_t_jones_20171212.pdf|Receiver, Bill Jones}}
 +    * {{::iandt.pdf|I&T, PICO specific, Bill}}
   * Planck decontamination, cooling, and in-orbit checkout   * Planck decontamination, cooling, and in-orbit checkout
   * Focal Plane configuration + ADR location + GRASP update (Karl)   * Focal Plane configuration + ADR location + GRASP update (Karl)
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 === Notes === === 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
 +
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imagerteleconnotes20180228.1519848079.txt.gz · Last modified: 2018/02/28 14:01 by hanany