NACO Quality Control: DARK frames

NACO Quality Control:
DARK frames

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read-noise | dark level | hot/cold pixels


QC PLOTS
	CURRENT	HISTORY
read-noise
ron
dark
dark_DCR
dark_FNS
dark_UCR
hot/cold pixels
QC1 database (advanced users): browse \| plot
Click on CURRENT to see the current trending (Health Check). Click on HISTORY to see the historical evolution of the trending.

A number of DARK frames is taken every day within the NACO daytime calibrations. Each DARK consists of 3 raw frames obtained with the instrumental setting matching the one used for science observations. The parameters matched are:

DET.DIT - detector integration time

DET.NDIT - number of sub-integrations

INS.OPTI7.NAME - camera

DET.NCORRS.NAME - detector read-out mode

DET.MODE.NAME - detector mode

In addition, each day, 3 dark frames are taken for the health check purpose, always with the same setup:

DET.DIT=1.7927 s, DET.NDIT=1, INS.OPTI7.NAME=S27, DET.NCORRS.NAME=FowlerNsamp, DET.MODE.NAME=HighSensitivity
DET.DIT=0.5 s, DET.NDIT=100, INS.OPTI7.NAME=S27, DET.NCORRS.NAME=Double_RdRstRd, DET.MODE.NAME=HighSensitivity
DET.DIT=300 s, DET.NDIT=1, INS.OPTI7.NAME=S27, DET.NCORRS.NAME=FowlerNsamp, DET.MODE.NAME=HighSensitivity

They are utilized to monitor performance of the NACO detector.

DARK frame - 0.5s, Double_RdRstRd, HighSensitivity This is an example of the master calibration DARK frame - NC_DCAL_0_5_S27_F_DRHS.fits. It is a pipeline product of the "naco_img_dark" recipe. The horizontal stripes on the edges of the detector are features characteristic to the Double_RdRstRd read-out mode.

DARK frame - 300s, FowlerNsamp, HighSensitivity This is an example of the master calibration DARK frame - NC_DCAL_300_S27_F_FSHS.fits. It is a pipeline product of the "naco_img_dark" recipe. The bright, diagonal stripes are associated with the "light leakage". They become prominent structures when darks are taken with long DITs.

top read-noise

QC1 parameters

parameter	QC1 database: table, name	procedure
"dark_ron12": read-out noise	naco_dark, dark_ron12	read-out noise calculated from the 2nd-1st raw; it is a median of the standard deviations measured from 100 4x4 windows on the difference frame, multiplied by sqrt(NDIT/2)

The following plot shows the temporal evolution of the read-out noise for different detector read-out modes: DoubleReadResetRead (panel 1), Uncorrelated (panel 2), FowlerNSample, DIT <= 90s (panel 3), and FowlerNSample, DIT > 90s (panel 4). In case of the FowlerNSample mode the read-out noise was found to depend strongly on the DIT. Thus, it is separated for the short and long DITs.

The other plot combines all the read-out noise values separated by the detector read-out mode.

top dark level

QC1 parameters

parameter	QC1 database: table, name	procedure
"dark_median": median dark level (ADU/pixel/s)	naco_dark, dark_median	median dark level in the central part of the master dark
"dark_min": minimum of the dark level (ADU/pixel/s)	naco_dark, dark_min	calculated by the stcube function
"dark_max": maximum of the dark level (ADU/pixel/s)	naco_dark, dark_max	calculated by the stcube function

The health check plot shows the dark current median value measured for the daily darks taken with DIT=300s, DET.NCORRS.NAME=FowlerNSamp, DET.MODE.NAME=HighSensitivity (plot 1), and with DET.DIT=0.5s, DET.NCORRS.NAME=Double_RdRstRd, DET.MODE.NAME=HighSensitivity (plot 2).

Trending

The additional trending plots show the dark current median calculated for the darks taken with:

the DoubleRdRstRd read-out mode dark_DCR,

the FowlerNSamp read-out mode dark_FNS,

and

the Uncorrelated read-out mode dark_UCR

top hot/cold pixels

QC1 parameters

parameter	QC1 database: table, name	procedure
"num_cold": number of cold pixels	naco_dark, num_cold	calculated by the pipeline recipe naco_img_dark
"num_hot": number of hot pixels	naco_dark, num_hot	calculated by the pipeline recipe naco_img_dark

The trending plot shows the number of the hot and cold pixels measured in the dark frames. The data points are separated by the detector read-out mode.