CCD Test report

MARCONI-EEV 44-82
CCD name :
Serial number :
Type : Backside, Single layer AR Pixel size 15x15 µm
Number of photosensitive pixels 2048 x 4102 [HxV]
Number of outputs : 2
Overall rating : Science

Testing date: April 10 2001

Residual image

Residual image occurs when the CCD is either overexposed or when a CCD camera is first powered up.
Under these circumstances, electrons are found trapped at the silicon-silicon dioxide interface
that slowly de-trap into the pixel's potential well during the course of an exposure.
For very cold operating temperatures (-120°C), residual charge may take hours or even
days (depending on how long the sensor integrates) before the level of residual charge
seen is lost into the sensor's read-noise floor.


Just after setting FIERA online, we can observe a strong residual
effect (29e- for a 1800s exposure, at -120C).
(temperature:-120C, wavelength:630nm)


30s after the end of the previous image readout, few dark images have been taken consecutively to
observe the residual effects, and how this decreases.
No "on purpose action" has been made to decrease this effect (continuous CCD wiping, parrallel
clocks voltage modification, ...).

(temperature:-120C, exposure time:1800s)



The residual effect is almost not visible... and it is difficult to calculate its intensity expressed in e-.

No difference has been observed for different wavelength.