EM-CCD (Electron Multiplier CCD) camera

A CCD camera that achieves on-chip multiplication gain by impact ionization.  Because of the noise property associated with this multiplication process, the EM-CCD camera is suitable for extremely low-light, low-background applications.

Please refer to this link, if you would like to investigate the EM-CCD camera further. 


Etaloning is a phenomenon that occurs when the incident light interferes with the reflected light from the back surface of the silicon and causes varying sensitivity – dependent both on the spatial and the spectral position.

Excess noise

In the case of EM-CCD, multiplying of the signal in the multiplying register has noise associated with that process and this will influence the SNR. The noise caused by signal multiplying is called excess noise and is added to the signal. The excess noise F is calculated by the multiplying factor M and a ratio of the dispersion of a multiplying register input signal: σin and a dispersion of the multiplying register output signal: σout.

\[ F^2=\sigma^2_{out}/ M^2{\sigma^2_{in}} \]

Please refer to this link to see the influence of excess noise to the SNR.

External trigger mode

In external trigger mode, the camera receives timing signals via a trigger cable from external sources. The camera runs at a frame rate determined by the time between trigger inputs, but not less than the exposure time plus the readout time.