Signal-to-Noise
The performance of Gemini (prior to June 1994) is described in the SPIE Kona conference paper (McLean et al. 1994). Several improvements were made after than meeting which led to improved performance at wavelengths longer than 3 um. The following tables give the current estimates or measurements of important properties.
| Typical measured point source sensitivities on the 3-m telescope | |||||||
|---|---|---|---|---|---|---|---|
| Filter/Band (um) | B (e-/s/pix) | B (mag/arcsec2) | mZP | % | mlim, 3-sigma, 1 min | tFW | tblip |
| J (1.22, 0.29) | 1200 | 16.1 | 21.4 | 19 | 19.0 | 167 s | 2.1 s |
| H (1.63, 0.29) | 5000 | 14.3 | 21.2 | 33 | 17.8 | 40 s | 0.5 s |
| K (2.1, 0.35) | 10100 | 13.0 | 20.5 | 34 | 17.2 | 15 s | 0.4 s |
| nbL (3.6, 0.07) | 2.5 x 106 | 4.8 | 16.5 | 27 | 12 | 60 ms | 1.4 ms |
| Measured Detector Properties | ||
|---|---|---|
| Rockwell HgCdTe (NICMOS 3) | SBRC InSb | |
| Full Well | 200,000 electrons | 150,000 electrons |
| Q.E. (J) | 40 % | --- |
| Q.E. (H) | 60 % | --- |
| Q.E. (K) | 60 % | 70 % |
| Q.E. (L) | --- | 70 % |
| Mean Dark Current | < 1 e-/s/pixel | < 15 e-/s/pixel |
| Non-uniformity | 10 % | 5 % |
| Good Pixels | 99.6 % | 99.9 % |
| Noise in 8 reads (Fowler CDS) | 30 electons | 40 electrons |
Last modified: Mon Apr 21 04:05:01 PDT 2008 by Elinor Gates