Telecon Notes Sep 12, 2018

Attendance: Amy, Kris, Roger, Shaul, Karl, Qi

Regrets:

• Science descopes (Shaul, Amy)
• Technology descopes (Shaul, Amy, Roger)
• Technology implementation plan (Roger)

PICO imager telecon - 09/12/2018

Technology descopes

• To specify potential descopes we can see
• Roger: not sure whether technology descopes are technology driven, whether the technology maturation is the right place for them
• Amy: there are different descops, only tech descopes be in tech section
• Shaul: science descopes and techo descopes; tech descopes is about ready/not-ready technology; science is about science goals
• Potential tech descopes (Roger):
  • 1) high-freq detectors; 2) multi-chroic; 3) readout
    • 3) readout is straightforward, don't suggest it to be challenging
    • 1) high-freq detetors
      • Shaul: not sure if high-freq is challenging
      • Roger: agree that it’s not a challenge
      • Shaul: it could be a science descope
      • Amy: risk matrix; two dimensions: one is risk being relized, another is consequences;
      • Shaul: removing high-v is not just affecting galaxy science, they might affect foreground, they are necessary from some studies; it’s debatable if we decrease number of pixels on the focal plane but keep bands, or simply remove some bands
      • Shaul: we can be very open, “at the moment, we don’t know; at phase A, we will know; there will be more knowledge about foreground available”
      • Amy: comment, removing high-v bands does not save a lot of money though
    • 2) multi-chroic
      • Roger: sinuous antenna, 2 issues have been raised in the community
        • polarization rotation with sinuous antenna. This may become an issue. It is worse with broader bandwidth.
        • different edge tapers over 3 bands. is it acceptable? is it a bad idea?
        • Experiments are fielding these pixels and both will be tested. We should know by early 2020's
        • In both cases could go down to 2 band pixels. This allows other tech such as horn coupled.
      • Shaul: none of sound like tech risks, they are systematics risks; there are experiments in near future; we are not seeing developing tech is risky
      • Roger: developing reliable tech is risky
      • Shaul: it isn’t clear to me what is the place to discuss this, do we discuss this in tech or systematics? it isn’t clear,
      • Amy: we need to talk about if we don’t have three colors; how we distribute, majority goes to systematics; we need to talk about the risk if we don’t have those 3-color, what would we do? For that descope option
      • Amy: descope, we could not get 3-color, and therefore the solution is 2-color pixel, tech chapter or risk, not systematics; if we have 3-color, but with systematics, that should be in systematics
      • Shaul: agree; also points out that it will not be that we won’t have, it will be like we have those detectors, but systematics exceeds; if you have sensitivity, you can clean systematics. There are systematics, we will numerate these, and; these words should be in systematics
      • Amy: is there a reaslistic situation, that in 2022, not makes sense to fly 3-color?
      • Shaul: we should know that we have not developed 2-color in most of our bands either
      • Roger: there is no concern on 2-color; there is concern on 3-color
      • Amy: with greater confidence to build 2-color
      • Shaul: this needs a significant amount of work
      • Amy: agree with Shaul that it’s a lot of work; but being able to address risk of 3-color is maybe worthy
      • Shaul: how serious is this issue?
      • Shaul: agree that readout is not a challenge

Science descopes

• Amy: what to save money: shrinking the operation, scaling down requires less mechanical reduces cost;
• one thing that’s is simple would be to slow the spin speed, it would reduce the requirement on motor, makes it easier to point reconstruction, data transfer and data on board. EPIC half rpm?
• Kris: what is the range to reduce?
• Amy: now 1rpm, if half rpm, don’t know how much can save
• Shaul: from science point of view, the impact is on noise, more 1/f, not easy to quantify; that is something has to be assessed by simulation
• Shaul: all of the small scale science should be fine, the only science affected could be largest angular scale and B modes; we can simply say “the effect on the largest angular scale will be accessed”.
• Amy: for baseline, it was 950 M, under 1B cap. Last decade, EPIC review increased 20-30%; showing some descopes is safer