A faint astronomical source delivers to a detector pixel of quantum efficiency

PHYSICS · Multi-part · Fermi University Physics · Optics & Photonics · Photodetection, photonic sources and quantum optics · Photodetection, photonic sources and quantum optics

What an Instrument Can See, Ch Radiance, etendue and a throughput budget that is spent

Problem

A faint astronomical source delivers

2.0\ \mathrm{photons\,s^{-1}}

to a detector pixel of quantum efficiency

90\%

. The exposure lasts

1000\ \mathrm{s}

. The pixel's dark current is

5.0\ \mathrm{electrons\,s^{-1}}

and its read noise is

5\ \mathrm{electrons}

(added once per readout). ((a)) Find the detected signal in electrons. ((b)) Find the signal-to-noise ratio, combining signal shot noise, dark-current shot noise and read noise in quadrature. Identify which noise term dominates the total noise.

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