SPEC: Info

Characteristic	Value	Comments
Detector	Hawaii-2	2048 x 2048
Minimum Exposure Time	2 s
Saturation	33,000 DN
Persistence	>500 DN	Occasionally seen at lower exposure levels
Bad Pixels
Typical Exposure Level	150 DN/s/wavelength channel	10th mag star, K-band, 20 mas scale, AO loops closed

SPEC: Measured Noise Characteristics

Characteristic	Integration Time	Mean	Median	Measurements
Dark Current	900 s	1.34 ± 0.60E-02 DN/s	1.34E-02 DN/s	112
Read Noise	900 s	12.81 ± 0.95 e-	12.52 e-	107

Gain = 0.23 DN/e- (assumed)
900 s is the most common OSIRIS integration time
All measurements are from dark images with SCURTMP = 68.0 ± 0.2 K
Dark current was determined by taking the mean and median values of the mean pixel value of individual dark frames
Read Noise was determined using the "2-bias method": RN = stdev(im1-im2) / sqrt(2) / gain; where im1 and im2 are darks and no account of the noise due to the dark current was considered.
This implies the stated read noise is an upper limit.

Long-term Monitoring Noise Plots

Dark Current	Read Noise

Notes: Negative values are not understood Values above 0.02 DN/s are thought to be shortly after a detector reset	Notes: Values above 14 e- are thought to be from images shortly after a detector reset

Noise Plots vs. Integration Time

Dark Current	Read Noise

Notes: Dark current values in the shorter integration times appear significantly influenced by the reset anomaly of the Hawaii-2 detector. The true dark current appears to be asymptotic value towards longer integration times.	Notes: Read noise values are uncorrected for the contribution by noise of the dark current.