|Figure 1: Multi-point hydrogen leak detection system for the NASA Stennis Space Centers cryogenic liquids handling technology|
A new-generation hydrogen sensor that is smaller, faster, sturdier, and less expensive to manufacture has been developed at Sandia National Laboratories. Early versions of this practical, reliable device for detecting hydrogen already have completed the design, fabrication, and test stages and are now in field application.
Existing techniques for detecting hydrogen have numerous drawbacks: limited dynamic range; poor reproducibility and reversibility; subject to false alarms; and tend to be slow, unreliable, and difficult to use.
In comparison, the Sandia sensor provides:
The sensor also exhibits outstanding reproducibility and reversibility, and good long term stability. It is manufacturable with standard microelectronics technology, and the sensor is simple to use.
|Figure 2: Sandias Robust, Wide-Range Hydrogen Sensor overcomes the limitations of existing hydrogen sensing technologies.|
A broad list of potential applications has been identified, such as:
The sensors are presently being used in a multi-point hydrogen leak detection system at NASAs Stennis Space Center (see Figure 1). Work is underway to use the devices in a number of additional NASA ground-based and flight systems. The sensors also have been used in two field applications--one in support of environmental monitoring at one of Hanfords waste sites and another involving nuclear reactor safety.
|Figure 3: Cross section of Sandias Robust, Wide-Range Hydrogen Sensor. Integration of sensing alloys with the CMOS technology allows fabrication of control electronics on-chip with the sensor elements.|
This new technology--known as the Robust, Wide-Range Hydrogen Sensor (shown in Figures 2 and 3)--was created by integrating special catalytic alloy films into Sandias existing complementary metal oxide semiconductor (CMOS) microelectronic technology. The hydrogen sensor uses catalytic palladium nickel (PdNi) gate metallization on field effect transistor sensors for detecting low concentrations of hydrogen (part per million); PdNi resistor sensors for detecting higher concentrations of hydrogen (up to 100%); and on-chip micro-thermometers and micro-heaters for maintaining constant chip temperature (see cross section in Figure 3). Custom control, communication, and other special function electronics can be fabricated on the same small piece of silicon containing the sensor elements. The unique PdNi catalytic alloy used in this project has been patented. This technology has been exclusively licensed by H2scan LLC of Valencia, California, Phone: (661) 775 9575. H2scan is interested in OEM and other partnering arrangements for specific applications of the hydrogen sensor.
Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy.
Last modified: May 14, 2003
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