Science Operations




LMIRcam was upgraded to HAWAII-2RG (H2RG) HgCdTe detector in 2018. This detector is 2048 x 2048 pixels2.  The outer pixels are vignetted.  In Summer of 2017 LMIRcam electronics were upgraded with Teledyne’s SIDECAR electronics. 
The LMIRcam plate scale is ~10.7mas/pix with a FoV 22 arcseconds squared.  Due to vignetting at the edges this FoV is closer to 18 arcseconds squared.


The dark current and read noise are low, allowing for background-limited observations in most imaging and spectroscopic configurations. There is significant persistence and nonlinearity with these detectors. Detector characterization in progress.  
 Detector Area(pixels) See Readout Stripes 2048×2048 2048×2048 1024×1024
 Pixel Scale(mas/pixels) 10.7 10.7 10.7 17.9
 Frame Time [s] see Readout Stripes 0.4918 1.4753 TDB
Saturation Level 3900 62000 62000 16000
5% non-linearity 2900 47500 47500 N/A
Bias Level 500 5000 5000 1200-2500
Dark Count 2 18 18 TDB
Read Noise 2 35 40 15-30

Sub windowing is available for LMIRCAM in FAST mode only. Minimum exposure time scales linearly with the vertical pixel size.

Readout Stripes

 Label  First Row Last Row Frame Time [ms]
 Full Image 1 2048 27.5
Center_Stripe_1024 513 1536 13.7
Center_Stripe_512 1025 1536 6.9
Center_Stripe_256 1025 1280 3.4


Saturation is around 64K counts. ??% non linear at ~40K. Persistence is negligible.


All near-infrared detectors are non-linear. The script should be run about once per run. The script takes a series of exposures intended to cover the full dynamic range of the detector and allows the users to characterize the linearization fit across the detector. If you work with high-dynamic range data or you care about doing higher precision photometry, it will be very important to linearize your data.  


At the speed the detector is read out, there is some crosstalk. For sources where the PSF core is saturated, evidence of channel crosstalk can be observed as dark spots on either side of the PSFs (approximately 64 pixels away to the left and right).