Strawperson Donut/Double-Ring Configurations

by Min S. Yun & L. Kogan

Design Considerations:

  1. A scaling factor of 2.1 to the next largest array
  2. Minimum sidelobe optimization for 20 synthesized beam radius
  3. "5 degree slop" digital mask
  4. Maximum pad re-use (50%)
  5. Short baselines in all configurations
  6. 10% N-S elongation
  7. Hybrid configurations with large N-S elongation
  8. Easy access to interior antennas in E-array


5 Basic Configurations:

Summary of the ALMA strawperson configurations.

Array

Minimum

Maximum

Time for

Natural

 

Baseline

Baseline

FOC = 0.4

Beam at 345 GHz

 

[m]

[m]

[hours]

[arcs]

A

85

3000

10

0.050

B

35

1430

4

0.101

C

15

680

1.5

0.22

D

15

325

0.5

0.47

E

15

150

0.02

0.97



Fraction of the uv cells sampled by each configuration with earth rotation. A reasonable target for good imaging is thought to be about 40%.