Andor Technology iXon3 Series User Manual

Page 64
iXon 3
Hardware
4.1.4 - What applications are EMCCDs suitable for?
EMCCD based detectors have been designed for the most demanding of low light, dynamic applications. These
detectors have redened the sensitivity expectations of scientic grade cameras, with a detection limit as low as single
photons.
These levels of sensitivity are vital for low light, life science and physical science imaging applications such as single
molecule detection, live cell microscopy, weak luminescence detection, or demanding astronomy applications (to name
only a few).
4.1.5 - What is Andor Technology’s experience with EMCCDs?
Andor Technology was the rst company to introduce an EMCCD based detector in 2000. Since then the company has
led the way in the development of EMCCD detectors, introducing the rst back illuminated EMCCD in January 2003.
Andor now offers the widest range of EMCCD based detectors on the market. The company is also playing a pivotal role
in increasing our understanding of this ground-breaking technology.
In September 2003 it hosted the 1st International EMCCD Symposium in Limavady, Northern Ireland, a dedicated
conference which looked at the current usage and future development of EMCCDs. This was followed in April 2005 by
the 2nd International EMCCD Symposium, held in Connecticut, USA. Please go to www.emccd.com for further details.
4.2 - EMCCD SENSOR
The EMCCD sensor is the core enabling technology of the system. Everything else in the camera has been designed
to extract the absolute best operational performance from this sensor. All EMCCD sensors in the iXon3 range have a
frame transfer architecture. The frame-transfer EMCCD uses a two-part sensor in which one-half of the array is used as
a storage region and is protected from light by a light-tight mask. Incoming photons are allowed to fall on the uncovered
portion of the array and the accumulated charge is then rapidly shifted into the masked storage region for transfer to the
serial output register. While the signal is being integrated on the light-sensitive portion of the sensor, the stored charge
is read out. Frame transfer devices have typically faster frame rates than full frame devices and have the advantage of a
high duty cycle i.e. the sensor is always collecting light.
A potential disadvantage of this architecture is the charge smearing during the transfer from the light-sensitive to
the masked regions of the CCD, (although they are signicantly better than full frame devices).The smearing being
more prevalent when exposure times are closer to the time taken to shift the charge under the mask (in the order of
milliseconds).
The Andor iXon3 is the best camera on the market for minimizing such smear, as the vertical clock speeds can be tuned
via the software to deliver the fastest parallel shifts in the industry, which has the further advantage of faster overall
framerates(especiallywhenusingsub-arrayand/orpixelbinningreadoutoptions).
Essentially, the EMCCD sensor is capable of detecting single photon events without an image intensier, achievable by
way of a unique electron multiplying structure built into the chip. Traditional CCD cameras offered high sensitivity, with
readoutnoisesinsinglegure<10e-butattheexpenseofslowreadout.Hencetheywereoftenreferredtoas‘slow
scan’ cameras. The fundamental constraint came from the CCD charge amplier. To have high speed operation the
bandwidth of the charge amplier needs to be as wide as possible but it is a fundamental principle that the noise scales
with the bandwidth of the amplier hence higher speed ampliers have higher noise.

Andor Technology iXon3 Series Specifications

General

Brand	Andor Technology
Model	iXon3 Series
Category	Digital Camera
Language	English