====== Telecon 20171212 ======

Attending: Tom, Joy, Brian, Shaul, Karl, Qi, Toki, Jeff, Julian, Al, Jacques

Notes by : Karl \\

=== Agenda===
  * No telecon next week 
  * Preparations for TeamX (JPL + UMN, led by Brian/Amy)
  * Cosmic Rays (Jeff Filippini) [[http://indico.ipmu.jp/indico/event/143/session/3/contribution/51|B-mode from Space slides]]
  * GRASP (Brad)
  * {{::focalplane_update_20171212.pdf|Focal plane model, V3.0}} (Young)

=== Notes:===

No telecon next week (TeamX meeting)

Preparations for TeamX (JPL + UMN, led by Brian/Amy)
  * Brian making a list of files TeamX needs.
    * CodeV files.  .seq files.
      * prep a 1.6 m and 1.2 m versions.  **UMN**
      * 1.4 m with coma-correction and without.  **UMN**
    * Kevin's current thermal model
    * Will get files/numbers from Roger. In email to Shaul: 0.8 uW on 100 mK, 1.8 uW on 350 mK. for TDM.
      * Shaul will ensure Roger has a wire count for FDM.
    * Cryogenics, ADR cooling power 10 uW. Kevin made a model that works for this.
    * Roger estimated FP mass, for 12-15k detectors estimate 7-8 kg.
      * in EPIC-IM a 1.5 m focal plane was 26 kg.
      * Core had similar focal plane size with waveguides and was 8 kg.

Cosmic Rays (Jeff Filippini) B-mode from Space slides
  * first 2-3 slides are intro to problem.  Rest are data from SPIDER
  * Antarctic balloons good approximation of space at L2
  * impact rate set by area, deposition energy set by thickness.
  * Planck issue was wafer hits. long time constant (seconds) and high rate (few Hz)
  * new space mission, wafers hit at 100 Hz. need short time constants. need bolometers unresponsive to cosmic ray hits on wafers.
    * should be able to absorb ballistic phonons and cool to thermal if wafer is coated in a superconductor (or normal metal).
    * then heatsink wafer well.
  * if crosstalk of cosmic ray hits is nonlinear.  Could be issues.  increases the effective rate.
  * consider hits to readout electronics as well.  LC resonators could shift. SQUIDs respond. etc.
  * Shaul: anyone planning to test this? like the phonon down-conversion?
    * Jeff yes, in progess. and Berkeley is also testing this month.
  * SPIDER data. low coincidence rate, so no long distance propogation across wafer.
    * in lab tests see ~ 8 ms time constants. See saturated TES at high energies.
    * saw 'step' glitches. example of a weird thing. steps of 1 flux quantum.  Large cosmic ray causes SQUID to lose lock on rising edge.  Specific to TDM. Can be avoided in design.
      * Think about what readout does when large energy depositions.
  * Jeff: No evidence for bolometer response to cosmic rays hitting wafer.  Good sign, likely to avoid Planck's problem.
  * Shaul: what are 1st priorities to look for in EBEX data?
    * Jeff: Coincidence is good.
  * Shaul: Why does SPIDER see no long glitches?
    * Jeff: Better heat sinking. easier at 300 mK. 
  * Shaul: 100 mK measurements would be nice.  Really show the problem or not.
    * Jeff: 100 mK is planned at JPL.

GRASP (Brad)
  * Running, but Brad can't attend so topic delayed to next telecon.

Focal plane model, V3.0 (Young)
  * Focal plane with pixels and hexagonal wafers is laid out.
  * New sensitivity is 0.62 uK arcmin.
  * Version posted on wiki.
  * Toki: are all arrays < 150 mm wafer?  Karl: yes.