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imagerteleconnotes20171017 [2017/10/17 16:48] wenxx181imagerteleconnotes20171017 [2017/10/18 09:42] (current) kyoung
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 ====== Telecon 20171017 ====== ====== Telecon 20171017 ======
  
-Attending: Brian, +Attending: Brian, Julian, Shaul, Karl, Qi, Roger, Kris, Jacques
  
 __Agenda:__  __Agenda:__ 
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 Open Dragone: optical system + noise model + focal plane options (Young) Open Dragone: optical system + noise model + focal plane options (Young)
   * Size of pixel defined on lowest or middle frequency band.   * Size of pixel defined on lowest or middle frequency band.
-    * middle bandsmaller pixel, higher sensitivity +    * middle band means smaller pixel, higher sensitivity 
-    * 10 db edge taper + middle band size, overall the best in terms of mapping speed+    * 10 dB edge taper + middle band size, overall the best in terms of mapping speed 
 +    * lowest band has 4.8 dB edge taper
     * edge taper is at 4K stop     * edge taper is at 4K stop
 +    * Using 10 dB at middle of band moving forward.
  
-  * 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.+  * For Open Dragone, the DLFOV is small. The outer area of the 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.     * We don’t know what we need for low frequency, it depends on the synchrotron structures.
 +    * Plan is to optimize mirror shapes to increase ~150 GHZ DLFOV so trading low sensitivity for high sensitivity is an option.
  
   * Open Dragone Optics   * Open Dragone Optics
-    * V3.D: focal plane further from stop, linearly 10% more focal plane compared to base line +    * V3.D: focal plane further from stop, linearly 10% more focal plane compared to baseline 
-     * looks good, has room for mechanical works +     * looks good, has room for mechanical structure of focal plane 
-     * Karl is working on coma correction on this telescope, and hopefully we will have larger DLFOV **(AI)** +     * Karl is working on coma correction to this telescope, and hopefully we will have larger DLFOV **(AI)** 
-    * V4: 10% less DLFOV compared to baseline+    * V4: 10% less DLFOV compared to baseline.  Overall smaller telescope, allows roughly 2-3 deg. increase in alpha.
     * sensitivity calculation uses edge taper defined as lowest band, can be done using middle band     * sensitivity calculation uses edge taper defined as lowest band, can be done using middle band
  
 Large-aperture Cross Dragone (Wen) Large-aperture Cross Dragone (Wen)
-  * Why 50cm? De-scopedcost, with spectrometer +  * Follow-up to matrix from previous week.  Now we have a baffled, large cross dragone. 
- +  * Reminder: Why 50cm? De-scoped to save cost, if imager + spectrometer is emplemented. 
-  * Cross Dragone have large DLFOV if not limited by vignetting (blockage, mirror sizes etc) as current case+    * Still questions as to whether just 140cm --  50 cm saves cost.   
 +    * Idea here is to provide options to cost and be decided on by the EC. 
 +  * Cross Dragone has large DLFOV if not limited by vignetting (blockage, mirror sizes etc) 
 +    * current case is limited by vignetting and blockage, not image quality.
     * unlike Open Dragone case, we can trade detectors at low frequency for high-frequency detectors more easily     * unlike Open Dragone case, we can trade detectors at low frequency for high-frequency detectors more easily
     * ~ 3K detectors (Open)  VS ~ 5K detectors (Cross)     * ~ 3K detectors (Open)  VS ~ 5K detectors (Cross)
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   * We have filled the matrix of telescope categories   * We have filled the matrix of telescope categories
 +    * optics design is wrapping up.  Polishing will be done to improve sensitivities.
 +    * the large/small, open/cross options provide input to trade-off decisions.  
  
 Scan (Kris) Scan (Kris)
   * Simulation   * Simulation
-   use WMAP Q/U map in V band; alpha = 22 deg, beta = 73 deg, is close to WMAP+   note WMAP Q/U map in V band; Probe with alpha = 22 deg, beta = 73 deg, is close to WMAP
    * fast spin + different precession (fast, slow, very slow)    * fast spin + different precession (fast, slow, very slow)
-   slower precession, more non-smooth features, higher resolution needed+     for T spin 20s (3 rpm) is fast, Kris do 1 rpm **(AI)** 
 +     * slowest precession, more non-smooth features, higher resolution needed
    * LiteBird & Core use same convention of alpha and beta, Kris will change his definition    * LiteBird & Core use same convention of alpha and beta, Kris will change his definition
   * The simulations are the average over 1 year   * 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 +   * simulating over other different periods will be very useful, give more opportunities to look into the scanning. 
-   * Kris will do two-week simulation **(AI)**+     * Jacques: maps with no holes over week timescales are useful. 
 +     * Kris will do two-week simulation **(AI)**
  
 Scanning strategy Scanning strategy
-   * Julian: 6 + 1 parameters; precession angle alpha, spin angle beta, 3 rotation rates (spin, precession, HWP), radius of L2 orbit + moon light +   * Julian: 6 + 1 parameters; precession angle alpha, spin angle beta, 3 rotation rates (spin, precession, HWP), radius of L2 orbitdata (or sample) rate. 
-   * Jacques will lead to make tables in wiki **(AI)**+   * Jacques will lead to make table of scan drivers, wants, and evaluation metrics in wiki **(AI)** 
 +     * Shaul to make table of hardware or engineering limits on 6 + 1 parameters **(AI)**
    * Brian: there may not be many options of the L2 orbits    * Brian: there may not be many options of the L2 orbits
      * there could be, we need more information input from project      * 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 +     * Jacques: Planck had radius L2 = 300,000 km, small. Needed 380 kg fuel for insertion. 
-  * Kris: demonstration is also important +     * Brian and Amy to check details of L2 orbit **(AI)** 
-  20s (3 rpm) is fastKris do 1 rpm **(AI)** +  * Amy told Shaul that we will probably have a steerable antenna for tele-communication; also fly wheels for pointing 
-  * Shaul’s comments on this parameters study: 1) optimization of parameters; 2) systematics given parameters +  * Kris: demonstration of full scan + systematics + map making is also important 
-  * When mapping + noise correlation? As soon as we have the tables from Jacques, we will have a range of parameters. +    Julian: Agreethe machinery exists to do these sims.  They need to be in time domain.  They're computationally cheap.  Need limits on the input parameters and evaluation metrics. 
-  * Hardware table, Shaul **(AI)**+  * Shaul’s comments on this scan parameters study: 1) optimization of parameters; 2) systematics given parameters 
 +  * When mapping + noise correlation? Julian: As soon as we have the tables from Jacques, we will have a range of parameters. 
 +  
imagerteleconnotes20171017.1508276914.txt.gz · Last modified: 2017/10/17 16:48 by wenxx181