Science Operations

Detector Characteristics

Blue Channel Detectors
Chip 350 nm 400 nm 500 nm 650 nm 900 nm 1000 nm
1 53.8 81.3 85.4 78.8 28.3
2 56.1 83.7 88.2 80.1 27.3
3 53.8 81.1 83.8 76.8 27.4
4 56.3 77.7 80.5 75 28.3

 

Red Channel Detectors
Chip 350 nm 400 nm 500 nm 650 nm 900 nm 1000 nm
1 95.1 96.7 57.0 13.2
2 82.8 90.2 53.2 11.8
3 84.3 90.6 51.5 11.2
4 87.4 95.7 54.4 11.2

Gain and Readout Noise

The gain, readout noise and approximate bias level for each of the science detectors are listed in the tables below. The bias levels are not stable throughout the night, in particular the bias level decreases after the camera is turned on and only reaches a stable value after 20-25 biases. The dark current is almost negligible, 0.01 ADU/s.

 

Blue Channel
Chip Gain(e-/ADU) Readout Noise2 (ADU) Bias level3,4 (ADU)
1 1.96 5.2 549
2 2.09 4.8 537
3 2.06 4.8 522
4 1.98 5.0 521
Tech 1 5.5
Tech 2 5.2

 

Red Channel
Chip Gain1 (e-/ADU) Readout Noise2 (ADU) Bias level3,4 (ADU)
1 2.08 5.0 475
2 2.14 5.0 480
3 2.13 5.3 477
4 2.09 4.8 492
Tech 1 6.0
Tech 2 8.0
  1. Gains were remeasured in 2017 with controller 6 (Blue) and controller 1 (Red) and the values: LBCB 1.5, 1.8, 1.7, 1.8 and LBCR 1.8, 2, 2, 2 for chips 1, 2, 3 and 4; are consistent with the those provided in the commissioning reports.
  2. Readout noise was measured in the lab on 19 August 2010. For the science chips, these values are consistent with standard deviations measured from the series of biases taken on 16 Sep 2017.
  3. The average of the mean bias level for 25 biases taken on 16 Sep 2017.
  4. During summer shutdown in August 2018, the bias levels on both LBCB and LBCR were changed to ~300 ADU.