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2048 X 2048 pixels CCD LORAL 2k3eb Back illuminated W1-1


A complete characterization report of the LORAL W1-1(0,0) CCD is here.


The instrumental setup to obtain these images is very easy. We replaced the 100 mm quartz window of the Infrared lab. dewar with a 50 mm window and we used a shutter in front of the window as shown in figure. As ligth source we used a LED matrix that illuminates a white plexiglass window.

View of the instrumental setup: near the dewar is visible the ligth source. On the background you can see the CCD controller and the shutter controller.

dewar shutt

1 second (left panel) and 10 seconds (right panel) exposure time images of the LORAL 2k3eb BI W1-1 Back charged with Catalytic B coating

loralw1 1s loralw1 10s

Both images show, of course, a vignetting due to the small diameter of the window. In the 1 second (left) exposure image is evident a problem of trapping on the left side of the chip. This trouble disappears by increasing the signal, as is shown in the 10 seconds (right) exposure image. Furthermore the CCD is driven with clocks that have approriate waveform and levels. In this case the levels are: -4 Volts (low level) and +4 Volts (high level) for the serial clocks and -8 Volts +3 Volts for the parallel clocks.


By rising a little more the level of the parallel clocks from + 3 Volts to +4.1 Volts the problem of trapping at low signal level disappears as shown in the following images.

 

lorph4 1s  lorph4 10s

 


The figure below shows the gain ( K ) obtained using the photon transfer technique as described by Janesick et al. (Opt. Eng. 26, 972, 1987).
The b output is biased with VRD = 14.3 Volts, VDD = 24.1 Volts and VOG = 1 Volt, while the SUBSTRATE is connected to GND.
The CCD is operated in non-MPP mode.
The pixel readout time is 32 microseconds, including the video processing time (10 + 10 microseconds CDS integration ).
With these operating conditions we measured a readout noise of 5 electrons r.m.s.

 

fconv




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