UVB-100 Low Temperature Water Desorption System

Designed to desorb water vapor in high and ultra-high vacuum chambers, the UVB-100 Water Desorption System utilizes UV radiation to desorb layers of water vapor without the intense heat of IR or a radiant bakeout.

For surface analysis systems, using a UVB-100 means that you can load samples more quickly and without introducing water vapor into your system. For high vacuum systems, faster pump-down times mean more process runs and higher productivity.

Benefits include faster ultimate pressure in production systems, and quicker removal of desorbed water during pumpdown.
See UVB-100 product specification sheet (pdf) for more information.

For added safety when using the UVB-100, RBD also produces a handheld, easy-to-use battery powered UV-C Meter.

UVB-100 Theory

Layers of water vapor molecules on the inside of vacuum chambers can be desorbed by energizing them with ultra-violet radiation in the range of 190 to 200nm, which provides sufficient energy to break covalent bonds. The graphs below show the effect of UV energy on water, hydrogen, oxygen and CO2. In this case, the UV emitter was activated for 8 minutes and then turned off. You can see from the graphs that the water vapor desorption rate increased during the UV ON time and then dropped off significantly when the UV was turned OFF.

The second graph shows an increase in H and a significant increase in CO2 as well as a reduction in oxygen during the UV ON time and a corresponding decrease in CO2 and H when the UV was turned OFF. The CO2 will vary with the amount of hydrocarbon available for reaction with O free radicals and O3.

UVB-100 Water Graph

UVB-100 Gases Graph

Application Notes

For more information on the use of in-situ Ultraviolet Radiation to desorb water vapor we suggest the following publication:

Water vapor in vacuum systems by A Berman
The National Physical Laboratory of Israel, Danciger Bldg. Hebrew University, Jerusalem 91904, Israel
Accepted 12 December 1995. ;
Available online 5 February 1999.

The following application notes are modified versions of various editions of The Vacuum Chronicles, originally published by Phil Danielson. All of these articles are just as pertinent today for the UVB-100 as they were for the Phototron. UVB-100 System

History of the UVB-100

In the late 80s and early 90s, Phil Danielson produced the Phototron ultraviolet source which was used to effect the desorption of water vapor from vacuum system surfaces. After Phil’s company was sold, the Phototron was no longer produced. In speaking with many people about the effectiveness of the Phototron, we discovered a lot of people who thought that the Phototron worked very well, but others felt it was underpowered. In researching the conditions under which the Phototron was not effective, we determined that most likely the ultraviolet source selected was not the correct match for the size of the chamber. We found that if sufficient power is applied, that UV does effectively remove water vapor from vacuum systems exactly as Phil had described it in his many publications over the years.
RBD Instruments went back to the drawing board and designed a more powerful version of the Phototron, our UVB-100. We also added more adaptability for interfacing with vacuum process controllers and improved safety features.

Here is a link to Phil’s Website and a list of many useful vacuum related articles that he has written: http://www.vacuumlab.com/articles.htm

UVB-100 Emitter Options

Flange Mounting:
2.75 CF or NW40 (K150) KF

Bakeout Temperature:
Standard emitter – 150° C
High Temp emitter - > 150° C

Note that the Standard emitter will work on most radiant baked systems.

UVB-100 Emitter Flange Options

(CF (top) and KF (bottom) style flanges)

UV Safety Considerations

There are no immediate warning symptoms to indicate overexposure of UV radiation. Symptoms of overexposure can include sunburn on skin or photokeratitis (an inflammation of the cornea) or photoconjunctivitis (an inflammation of the conjunctiva, the membrane that lines the inside of the eyelids) in eyes and typically appear hours after exposure has occurred.
Photokeratitis and photoconjunctivitis can be very painful, however, they are reversible and do not seem to result in any long-term damage to the eye or vision.

Special UV Safety Practices

Never allow the skin or eyes to be exposed to UV radiation sources. The UV radiation generated by laboratory equipment such as the UVB-100 can exceed recommended exposure limits and cause injury with exposures as brief as three seconds in duration.
The UVB-100 should never be operated when the system is up to air and vacuum ports are open. To ensure this, the control is key operated. Ensure that proper safety protocol is followed at all times when operating the UVB-100.