Question

An astronomer is using a CCD with responsive quantum efficiency of 80%, readout noise of 5 e/pixel rms, bias level of 1000 e/pixel, well depth of 151,000 electrons, and 16-bit analogue-to-digital conversion. She is recording a flat-field, with a flux of 10,000 photons/second impinging on each CCD pixel.

(i) What is the dynamic range of the CCD?

(ii) What is the countrate (i.e. detected flux per second) per pixel?

(iii) After what exposure time will the image become saturated?

(iv) If the CCD gain is 4 e/ADU, what would be the saturation value be, in units of ADU?

(v) What is the maximum quantisation noise in this case?

Answer 1