Quality Control and
Data Processing

HC PLOTS
Dark current
QC1 database (advanced users): browse | plot

Dark exposures are measured regularly for all read-out modes and detector binnings (1x1, 2x1, 4x2, and 8x4). A typical set consists of five exposures of 3600 secs per mode.

Dark frame. Example raw frame for the blue detector. The different levels for the 16 read-out ports are due to differences in the bias

QC1_parameters

FITS key	QC1 database: table, name	definition	class*	HC_plot**	more docu
none	espresso_dark..dark_mean_avg	average dark current across read-out ports [ADU/px/hour]	HC		[docuSys coming]
none	espresso_dark..dark_mean_rms	RMS of dark current across read-out ports [ADU/px/hour]	HC		[docuSys coming]
*Class: KPI - instrument performance; HC - instrument health; CAL - calibration quality; ENG - engineering parameter **There might be more than one.

ESPRESSO has two chips, one for the BLUE and one for the RED arm. Each chip has 16 read-out ports. Dark QC parameters are determined by the pipeline per read-out port which leads to 16 different values for each QC parameter per chip. They are written as header keys in the form of (for the mean dark current):

QC.EXT<n>.ROX<x>.ROY<y>.DARK.MEAN

with <n> being the detector (0 for BLUE and 1 for RED), <x> the x position of the read-out on the chip (0, 1, to 7), and <Y> the y position (0 or 1). The corresponding names in the QC1 database follow the scheme

dark_mean_<x>_<y> .

In addition to these individual values, the average and the RMS per chip are calculated and written into the QC1 database.

Trending

The dark current is trended separately for the four different read-out modes: 1x1 binning (fast read-out), and 2x1, 4x2, and 8x4 binning (all slow read-out).

Scoring&thresholds Dark current

The average and RMS QC parameters are scored per detector. Thresholds have been set according to the measured values during commissioning.

History

None.

Algorithm Dark current

The dark current (ADU/px/hour) is determined by the pipeline recipe per read-out port. The QC procedures calculate in addition the average and the RMS of all 16 ports per detector.