Memo Title:                        MityCCD Noise Analysis Summary

Memo Number:                  0010

Revision No.:                      2.0

Date:                                    28-Sep-2009

This document explores some of the sources of noise in the MityCCD scientific camera. The level of contribution of each type of noise changes with the type of sensor and the application.

The major sources of noise are:

Shot Noise From Dark Current – Dark current is a thermally generated current, which stems from impurities in the silicon. Dark current in CCDs can be significantly reduced by cooling.  Dark current itself is not a problem, since it is, on average, repeatable and can be subtracted off from images.  Shot noise is a quantum noise effect related to the discreteness of photons and electrons [2].  It is a statistical component of the dark current and can be quantified as the square-root of the dark current. 

Readout Noise – Readout noise contribution in a CCD is due to the readout electronics of the CCD, i.e. the on-chip amplifier.

Electronics Noise – Electronics noise is the noise generated due to the external hardware and gain circuitry in a CCD scientific camera.

The total system noise can be defined by the equation below [1].

Total Noise = √(Readout Noise ² + Shot Noise ² + Electronics Noise ²)

For short exposures, i.e. little or negligible contribution due to dark current shot noise the total noise can be calculated as

Total Noise = √Readout Noise ² + Electronics Noise ²

The table below shows a comparison of some of the CCD scientific cameras offered by Critical Link and their performance.

Table 1 : MityCCD Camera Performance Summary