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| imagerteleconnotes20180228 [2018/02/28 14:01] – hanany | imagerteleconnotes20180228 [2018/02/28 16:27] (current) – kyoung | ||
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| ====== Telecon 20180228 ====== | ====== Telecon 20180228 ====== | ||
| - | Attending: | + | Attending: |
| - | Notes by : \\ | + | Notes by : Qi\\ |
| === Agenda=== | === Agenda=== | ||
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| * {{:: | * {{:: | ||
| * {{:: | * {{:: | ||
| + | * {{:: | ||
| * Planck decontamination, | * Planck decontamination, | ||
| * Focal Plane configuration + ADR location + GRASP update (Karl) | * Focal Plane configuration + ADR location + GRASP update (Karl) | ||
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| === Notes === | === Notes === | ||
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| + | * **Planck decontamination, | ||
| + | * Someone needed to write ~ 1 paragraph. | ||
| + | * 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, | ||
| + | * May,2006 | ||
| + | * cryogenic, photometry, cooling down to 40 K, measuring surface separation | ||
| + | * July,2006 | ||
| + | * same run as above, to do calibration, | ||
| + | * 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, | ||
| + | * 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, | ||
| + | * 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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