Tech Briefs

Description

Ion chambers are type of radiation detector that are used to measure the concentration of tritium in the gas phase. However, ion chambers gradually become covered with tritiated surface contaminants, which create a large background signal that obscures measurement. Previous efforts to reduce this “memory effect” include using gold coatings and electrodes with reduced surface areas. These approaches add to the cost and complexity of the instrument and only slow down the effect, instead of preventing it. Therefore, ion chambers must be periodically cleaned by hand, which increases the risk of worker exposure and instrument breakage. Periodic cleaning also does not address tritium level ambiguities created by an increasing background signal. An ideal solution to this issue would be to either develop an ion chamber that does not accrue surface contamination, or one that is self-cleaning while it is in operation.

This technology uses LED light illumination to desorb contamination from ion chambers while they are in operation, preventing the appearance of the negative effects of surface contamination. The concept benefits from the rapid improvement in LED technology that affords robust, long-lasting, and powerful light sources that can stimulate desorption. In addition to the benefits of a backgroundless ion chamber, this technology represents a large potential cost saving by negating the need for gold coatings because it works on both gold and other surfaces, such as stainless steel.