Specifications

Version 1.1 rev Jan 2013
Page 24
iXon Ultra
Introduction to iXon Ultra Hardware
1.7.9 - EM Gain ageing
It has been observed that some EMCCD sensors, more notably in cameras that incorporate L3Vision sensors from e2v,
are susceptible to EM Gain fall-off over a period of time. This ageing effect applies to any EMCCD camera manufacturer
that incorporates L3Vision sensors into their cameras. The Andor iXon Ultra 897 model uses an L3Vision sensor.
A technical note entitled: ‘EMCCD - RealGain
TM
& EMCAL
TM
’ , which further explains this phenomenon, can be
downloaded from the following website: http://www.andor.com/library/publications/?app=543
If left unchecked, this ageing phenomenon has the potential to signicantly compromise the long-term quantitative
reliability of EMCCD cameras. Andor has recognized this ageing issue and has implemented innovative measures to
stabilize the EM Gain on these sensors, ensuring that this ground-breaking ultra-sensitive technology can deliver a
prolonged quantitative service to the user and if these highly sensitive sensors are used with due care and attention,
ageing can be minimized and should not present any real problem to the user.
More details of this ageing effect and Andor’s solutions can be found on Section 3.1.7 on page 46. Some of the
guidelines to minimize the EM Gain ageing process are listed below:
• DonotuseEMGainvaluesgreaterthannecessarytoovercomethereadnoise.Againofx4orx5thermsread
noise (accessible from the spec sheet or performance sheet) is more than sufcient to render this noise source
negligible. In practice, this can be achieved with EM Gain of less than x300 at 10 MHz and x450 for 17MHz
operation. Pushing gain beyond this value would give little or no extra Signal to Noise benet and would only
reduce dynamic range.
• OnlyselecttheextendedEMGainscaleofx1000forsinglephotoncountingapplicationsandalwaysensure
that the signal falling onto the sensor is within the regime of low numbers of photons per pixel.
• Turndownthegainwhenthecameraisnotacquiring.
• Trynottoover-saturatetheEMCCDsensor.