EXFO X-Cite exacte System

The X-Cite® exacte is a research grade broad spectrum light source that excites a wide range of fluorophores. In addition to the functions of its cousins (the X-Cite 120 XL and X-Cite 120PC XL), the X-Cite exacte has a DC powered lamp with patented Closed-Loop Feedback engineered so that 1. it illumination output is stable, 2. the user can adjust the intensity with fine precision , 3. the instrument incorporates a high speed shutter, and 4. with the optional X-Cite Radiometer then the output can be calibrated precisely allowing uncommonly precise repeatability.

The X-Cite® exacte is provided with software that presents a Graphical User Interface (GUI) that enables the operator to employ a PC to control it's lamp, iris and shutter. X-Cite® exacte Control Panel software also logs events (exporting data in .csv format), records and displays real-time stability data. This is ideal for verifying intensity stability during automated or long term experiments. These functions can be controlled either locally or remotely via PC computer, or controlled by an automated instrument. The straightforward command set easily allows integration into automated systems as well as with commercially available imaging software platforms, or write your own scripts!

Right: X-Cite exacte DC Illumination System
Click on image to see enlarged view.

The X-Cite illuminators are compatible with modern microscopes from all major manufacturers, or could be employed as a standalone coaxial or off axis illuminator for other applications including uses with other lenses and film or digital imaging systems. The light is pumped through a Liquid Light Guide (LLG) that ensures homogeneity at the delivery end. Because of the length of the LLG (several lengths are available, or a custom LLG can be made) the X-Cite unit can remain far enough away from the microscope so that heat and vibration do not interfere with the observations.

X-Cite® exacte employs an optimized 200 watt Mercury Vapor Short Arc, DC lamp that warms up in about four (4) minutes to deliver rich spectral excitation across a uniformly illuminated field from 340 to 675 nm. The proprietary Intelli-Lamp® technology provides more than 2,000 hours (2,500 typical) of life, and the advanced circuity provides a consistent output is maintained over all of this lifespan. The lamp is a module that aligned at the factory and so changing the lamp is a safer and simple, one-step process. The provided adjustable iris allows the operator to set the level of illumination in 1% increments between 100% down to 0%. This is ideally suited to routine fluorescence assays and use in multi-user facilities.

EXFO short arc lamps for AC (X-Cite® 120 series) or DC (X-Cite® exacte) operation burn in an atmosphere of mercury vapour at high pressure. In cold lamps (i.e. at room temperature) metallic droplets of mercury can be seen in the lamp bulb. During operation of the lamp the mercury vaporizes due to heating of the discharge tube (lamp body) and the gas between the electrodes approaches temperatures of up to 10,000°C. The temperature of the discharge tube reaches approximately 800°C. After the lamp is in thermal equilibrium (5 to 10 minutes after ignition), the vaporized mercury gives rise to a pressure routinely of 30 to 75 times the atmospheric pressure.

Caution: any HG LAMP CONTAINS MERCURY. Inhaling mercury vapour or small particles of mercury or its compounds can be harmful to lungs, kidneys and the nervous system. Injuries to oneÕs health can arise due to penetration of the skin or resorption via the gastro-enteric tract. So manage these risks in accord with Disposal Laws and refer to www.lamprecycle.org, or call 1-800-668-8752. Lamps sold by Company Seven may be returned in their original packaging to us; contact Company Seven in advance to obtain Return Authorization and instructions. Otherwise return directly to EXFO in the original packaging for disposal in the appropriate manner. For additional information about this refer to Mercury Safety Instructions for Short Arc Lamps in our Library.

Above: Spectral output of X-Cite® exacte Mercury Arc Lamp compared to HBO 100 Watt Mercury source.
Click on image to see an enlarged view (84,878 bytes).

A valuable attribute of X-Cite exacte is how is Closed Loop Feedback system works to maintain consistent output over time, see the simulation below:

Above: X-Cite® exacte with Closed Loop Feedback system 'On'. Illumination intensity remains consistent throughout.
Above: Lamp with none or with Closed Loop Feedback system 'Off' and so as lamp ages, the intensity diminishes.