Monthly Archives: April 2012

Opt-Diss 405 Detector

When discussing and demonstrating the Distek Opt-Diss 405 fiber-optic UV spectrophotometer, many customers have asked what type of detector the system uses to capture images in the UV spectrum.  

The Opt-Diss 405 utilizes a single charge-coupled device (CCD) as the system’s detector.  CCD’s were first developed in 1969 at AT&T’s Bell Labs, and have been applied most commonly for usage in digital cameras. 

The basic concept behind the CCD is that light falls upon an array of capacitors (the photoactive region), causing each capacitor to accumulate a charge proportional to the light intensity at each location.  A control circuit is then able to convert these charges into a sequence of voltages, which can then be converted into data by digital devices.  And by cooling a CCD (with the Peltier cooler, in the case of the Opt-Diss 405), the device becomes sensitive to the UV region of the electromagnetic spectrum.  

 

 

 

 

 

With the Opt-Diss 405, if the user clicks on the “View Image” icon or command in the software, one can actually see a digital representation of the CCD, and where the light from each channel falls on the detector (pictured below).

 

 

 

 

Using a CCD, the Opt-Diss 405 is able to acquire the entire UV spectrum simultaneously with every image collected.

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Dip Probe vs. Arch Probe

The Distek Opt-Diss 405 fiber-optic UV spectrophotometer utilizes the patented Arch probes in order to acquire absorbance-data in-situ.  Other fiber-optic systems use a different style probe called dip probes.  The Distek Arch probes have several advantages over the dip probes, thereby ensuring better results for in-situ UV analysis:

1) With a dip probe, the UV light has to reflect through a horizontally placed prism in order to be retransmitted back to the detector.  These horizontal surfaces allow either particulate matter to collect on the bottom surface of the prism, or air bubbles to be trapped underneath the top surface (shown above). 

2) The profile of an Arch probe is smaller and thinner than a dip probe, so there are less hydrodynamic effects from the Arch probe as it resides in the vessel.

3) The Arch probe has a wide-range of pathlengths, from 0.25mm to 10mm.  The shortest pathlength that a dip probe can be made in is 1mm.

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Certified Pre-Owned Spring Cleaning!

In Distek’s Certified Pre-Owned Department, spring not only brings fresh air and flowers but it also brings an opportunity to do some spring cleaning.  

Order any Certified Pre-Owned Instrument by June 20, 2012, and you will receive an additional six-month warranty on top of the already standard six-month Distek-backed warranty. 

That is a full year warranty, a $1500 value, on every Certified Pre-Owned Instrument!

Visit our Certified Pre-Owned Homepage for a complete list of all available instruments.

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