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Instrumentation Working Group

Page history last edited by Tony Mroczkowski 1 year, 10 months ago

Instrumentation working group

 

Directors: Tony Mroczkowski and Omid Noroozian

(amroczko@eso.org, onorooz@nrao.edu)

Membership:

email for the list is here: atlast-instrumentation@eso.org

https://www.eso.org/lists/listinfo/atlast-instrumentation

 

Some types of instrumentation we want to consider:

  1. Kinetic inductance detectors: LEKIDs, on-chip waveguide gratings, waveguide filter banks, Martin-Puplet interferometers, etc.
  2. Transition edge sensors: SQUIDs, microwave MUX, code-domain multiplexers, various low-resolution direct-dection spectrometers as above.
  3. "Classic" bolometers (e.g. similar to Artemis)
  4. Heterodyne FPAs: SIS, MMIC HEMT
  5. Paramps (could be in FPAs)
  6. ALMA-compatible front end
  7. Polarimetry versions of all of the above.


May be better to split direct-detection and heterodyne.

Aspects to consider:

  1. what is the state of the art?
  2. what predictions can we make for the state of the art in 2025?
  3. what is the ultimate noise floor?
  4. how does the multiplexing scale?
  5. what technological challenges must be overcome for the technology to fill a >1 square degree field of view? 
  6. what kind of spectral resolution can we attain?
  7. what is the bandwidth (including multichroics)?
  8. several of the above feed into mapping speed. How does the overall mapping speed compare to that of the ALMA 12-meter array (assuming 16 GHz bandwidth)?
  9. What are its prospects for polarimetry, either from the start or as an upgrade?

 

AtLAST instrument white paper:

https://www.overleaf.com/12954663cjfncytwbwpy#/49588118/

 

Some atmospheric considerations:

 

These are based on Scott Paine's am code models for the average transmission in the best 5th, 25th, 50th, 75th, and 95th percentile conditions (source: https://www.cfa.harvard.edu/~spaine/am/cookbook/unix/sites/ALMA/).  For these, I computed the values from 0-2 THz as such:

am ALMA/ALMA_annual_50.amc  0 GHz  2000 GHz  10 MHz  0 deg  1.0

the output file format has these columns:

frequency(GHz) Tau Transmission T_Rayleigh-Jeans T_brightness

 

ALMA_annual_05_percent_0_2000_GHz_zenith.txt

ALMA_annual_25_percent_0_2000_GHz_zenith.txt

ALMA_annual_50_percent_0_2000_GHz_zenith.txt

ALMA_annual_75_percent_0_2000_GHz_zenith.txt

ALMA_annual_95_percent_0_2000_GHz_zenith.txt

 

Using the values from http://www.ccatobservatory.org/index.cfm/page/observatory/Site_Facts/Characterization_Instr/Weather_Data.htm to modify the am models for the ALMA site, seting the base pressure and temperature as appropriate, we have these comparisons of the transmission for Cerro Chajnantor and the plateau. The ratio of the transmissions is plotted for values where the transmission from the CCAT-prime site is >= 5%.


CerroChajnantor_annual_05_percent_0_2000_GHz_zenith.txt

CerroChajnantor_annual_25_percent_0_2000_GHz_zenith.txt

CerroChajnantor_annual_50_percent_0_2000_GHz_zenith.txt

CerroChajnantor_annual_75_percent_0_2000_GHz_zenith.txt

CerroChajnantor_annual_95_percent_0_2000_GHz_zenith.txt 

 

 

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