UVB-100 Low-Temperature Water Desorption /

Oxidative Hydrocarbon Removal System

Ideal for large O-ring sealed vacuum systems and load locks

 

Designed to desorb water vapor and remove oxidative hydrocarbon 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.


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


For more information on water vapor and it's effects on vacuum chambers, please see this collection of articles (compiled by Normandale Community College) by the late Phil Danielson (formally of The Vacuum Lab).


More information...  or call us at 541-550-5016

water-vapor-desorption-UVB-100


Testimonials


After an unfortunate oil contamination event in our UHV system, we were in need of a rapid method for cleaning the equipment without the time consuming process of completely disassembling the chamber. Having read that oxygen plasma is an effective method of removing hydrocarbon contamination, we decided to utilize the UVB-100 while backfilling the UHV chamber with O2 gas.


After installing the UVB-100 in the chamber, we turned off the high vacuum pumps and left only the scroll pump on. We then backfilled the chamber with ~10 Torr O2 gas and turned on the UVB-100. Due to the high flux of 185nm light emitted, abundant oxygen radicals were created which in turn reacted with the oil hydrocarbons adsorbed on the surface walls of the vacuum chamber, converting them to more volatile species (CO, CO2, H2O, etc) that could then be easily evacuated by the scroll pump. After leaving the system run in this state for 12 hours, we pumped the system back down and a residual gas analysis revealed that the majority of the contamination had been reduced to background levels. .


- Micah J. Schaible, Postdoctoral Researcher, Georgia Institute of Technology


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.


water-vapor-desorption-graph       water-vapor-desorption-CO2-graph


Application Notes

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

Degassing a vacuum system with in-situ UV radiation.

(Journal of Vacuum Science & Technology A (Vol.30, Issue 6)_

 

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.

water-vapor-desorption-UVB-100-system

 

water-vapor-desorption-UVB-100


UVB-100 Solid Works Drawing

UVB-100 SOLIDWORKS® File

UVB-100 SOLIDWORKS

 


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.


Here is a link to Phil’s Website and a list of many useful vacuum related articles that he has written.


UVB-100 Emitter Options


Flange Mounting:
2.75 CF or NW40 (K150) KF
(other flange mounts are available on request)

water-vapor-desorption-UVC-emitter

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


UVC-Meter

UVC-meterRBD produces a hand-held UV meter that is an economical and accurate way to measure UV-C radiation. It is ideally suited as a safety tool to test for UV-C that may be passing though viewports in vacuum systems that have an internal source of UV-C, such as our UVB-100 water vapor desorbing emitter.

 

 

 

 


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.


Test Units

Try One!

Not sure if the UVB-100 will work for your application? Contact us for more information about our rental program. For a nominal rental charge, you can try a UVB-100 package for 30 days and see if you get the desired results. If so and you decide to purchase the package, then the rental fee is applied to the purchase price.