The effects of Co/sup 60/ gamma radiation on electron multiplying charge-coupled devices

Electron multiplying charge coupled devices (EMCCDs) utilize impact ionization to achieve subelectron noise up to video frame rates and above. This paper describes the effects of Co/sup 60/ irradiation on device performance parameters including the dark signal, charge transfer and multiplication gain. Devices were irradiated with different ionizing doses, and biases chosen to simulate operating conditions. The 'global' threshold voltage shift was measured to be around 0.14 V/krad (Si) for all devices. However, the multiplication gain was unchanged by the irradiation. The radiation-induced multiplication register component of dark signal was found to be an order of magnitude larger than that from the image section at room temperature, and to have lower temperature dependence.