Controlling EMCCD charge handling capacity through customized clocking

EMCCDs are capable of operating in both a standard CCD mode with high dynamic range and a low-light mode with single photon sensitivity. Standard CCD mode benefits from maximizing the image area FWC, while in photon counting mode passing large signals through the EM register should be avoided. Here, we present customized clocking schemes that enhance the image area FWC of 2-phase EMCCDs by nearly a third. Serial clocking schemes are presented that provide a user configurable level of control over the register FWC for the CCD201. This dynamic control of serial FWC provides a convenient and powerful means to control the signal passing through the EM register at high at high gain values, limiting the size of cosmic ray “tails”, reducing background detector noise while also acting as a means of protection against device ageing.