Parameters of CCD and CMOS cameras

by Christian Buil

This page gives the optoelectronic parameters measured by the author of some models of popular cameras used for astronomical observation.

 

For measurement of quantum efficiency (QE = quantum efficiency) I used as a reference the adapted value of the efficiency given by the manufacturer at the peak of sensitivity for the sensor KAF-3200ME (Kodak). With this exception, all profiles are derived from data measured by the author using spectrographs (Lhires III, Alpy 600) and stable light sources.

 

Note that I always give the « apparent » quantum efficiency (taking into account the windows of the camera and the protection  window of the detector itself). The absolute quantum yields displayed are therefore not strictly that of the detector alone, but the gap is quite small (slight under-evaluation of a few percent).

 

The electronic  gain (in electrons/ADU (e-/ADU) is given by the formulae:

where B is the mean value signal (in ADU) for a given area of a bias image, F is the mean value of the signal of the same area for a flat-field image (in ADU), σ(B1-B2) is the standard deviation of the pixels signal in the area of the difference of two bias images, σ(F1-F2)  is the standard  deviation of the pixels signal in the area of the différence of two flat field images.

 

The external camera (include detector) readout noise (RON) in electrons is given by:

The dark signal rate, in electrons/s/pixel, is given by:

where σADU is the standard deviation observed in the difference of two dark frame exposed each T seconds.

KAF-3200ME  (test camera : QSI 532)

Origin : Kodak

Type : CCD

Shutter type : global shutter

Number of pixel :  2184 x 1742

Pixel size : 6.80 microns

Electronic gain (G) : 1.413 e-/ADU

Read Out Noise (RON) : 12.6 e-

Dark signal at 0°C : 0.080 e-/s/pixel

Quantum Efficiency at 6563 A : 79%

Digital coding : 16 bits

Apparent charge capacity : 70000 e-

ICX694AGL  (test camera : ATIK 460EX)

Origin : Sony

Type : CCD

Shutter type : global shutter

Number of pixel :  2749 x 2199

Pixel size : 4.54 microns

Electronic gain (G) : 0.276 e-/ADU

Read Out Noise (RON) : 5.8 e-

Dark signal at 0°C : 0.0065 e-/s/pixel

Dark signal at -20°C : 0.0014 e-/s/pixel

Quantum Efficiency at 6563 A : 58%

Digital coding : 16 bits

Apparent charge capacity : 18000 e-

MN34230PL  (test camera : ASI1600MM)

Origin : Panasonic

Type : CMOS

Shutter type : rolling shutter

Number of pixel :  4656 x 3520

Pixel size : 3.80 microns

Electronic gain (G) : 0.477 e-/ADU (g = 20 dB)

Read Out Noise (RON) : 1.4 e- (g = 20 dB)

Dark signal at 0°C : 0.042 e-/s/pixel

Dark signal at -20°C : 0.010 e-/s/pixel

Quantum Efficiency at 6563 A : 39%

Digital coding : 12 bits

Apparent charge capacity : 1950e-

MN34230PL  (test camera : ASI1600MC)

Origin : Panasonic

Type : CMOS (CFA version)

Shutter type : rolling shutter

Number of pixel :  4656 x 3520

Pixel size : 3.80 microns

Electronic gain ( g = 20 dB) :

  - Red channel : 0.460 e-/ADU

  - Green channel : 0.460 e-/ADU

  - Bleu channel : 0.255 e-/ADU

Read Out Noise (RON) : 1.4 e- (g = 20 dB)

Quantum Efficiency at 6563 A : 34%

Digital coding : 12 bits

Apparent charge capacity : 1950e-

IMX290  (test camera : ASI290MM)

Origin : Sony

Type : CMOS (back illuminated)

Shutter type : rolling shutter

Number of pixel :  1936 x 1096

Pixel size : 2.90 microns

Electronic gain ( g = 20 dB) : 0.373 e-/ADU

Electronic gain (g = 40 dB) : 0.037 e-/ADU 

Read Out Noise (RON) : 1.26 e- (g = 20 dB)

Read Out Noise (RON) : 0.99 e- (g = 40 dB) 

Quantum Efficiency at 6563 A : 67%

Digital coding : 12 bits

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