ITEM            general
ITEM_TITLE      NONE

<b>2008-05-24:</b> GIRAFFE CCD &quot;Carreras&quot; operational (often called "new")
	      (replacing &quot;Bruce&quot;).
	      Both CCDs are identical in format and size.<p>
	<p><b>2011-01-11: </b>
	fast read mode added 
	<p><b>2016-04-01:</b>
	the 'slow' mode is offered in VM,
	calibration data are processed and QC parameters are available, but they are
	not trended  because of their very rare acquisition. <p>

      <p>A set of 5 BIAS frames is measured daily as part of the routine calibration
	        and health check plan. The BIAS level, the read noise and the
	structure are monitored.
	      <p> 'Normal' is the standard read mode of the CCD. The
	QC1 database has  also some data for the 'Fast' and the 'Slow' mode, but (with
	the exception of the BIAS plot) there are no HC plots for these rarely used
	modes.</p>
	      <p>Since October 2010, the fast readout mode is offered
	in addition to
	          the normal readout mode. Its trending plots are set up the same way
	as the ones for
	          normal read mode, find them under '<a
	href="/observing/dfo/quality/GIRAFFE/reports/HEALTH/trend_report_BIAS_HC.html">bias_Fast</a>'.

	<p>
	        Other CCD parameters are monitored using the <a
	href="/qc/GIRAFFE/reports/HEALTH/trend_report_DARK_HC.html">darks</a> and
	        the <a href="iflat_qc1.html"> image
	          flats</a>. </p>

TABLE_NAME	bias1
TABLE_TYPE	FIGURE_2
TABLE_WIDTH	60%
TABLE_IMG1	AHREF="../img/bias.gif"
TABLE_IMG1	"../img/bias.gif" width="140" height="270" border="1"
TABLE_CAP1	<b>BIAS frame</b>, old CCD. There is an upward gradient of the order of several ADU which is monitored by the STRUCTY parameter. The bright vertical feature is a bad column.
TABLE_IMG2	AHREF="../img/bias_new.png"
TABLE_IMG2	"../img/bias_new.png" width="140" height="286" border="1"
TABLE_CAP2	<b>BIAS frame</b>, new CCD. The new CCD has  cleaner cosmetics, there is no bad column. The gradients in X and Y are much smaller.