Project Title:
Rapid Sensor to Detect Leaks During Fueling Operations
94-1 13.01 4844 A
Rapid Sensor to Detect Leaks During Fueling Operations
Abstract:
An innovative microelectronic gas sensor utilizing plasma enhanced
chemical vapor deposited (PECVD) diamond in conjunction with a
catalytic metal has been fabricated and demonstrated in the
laboratory to detect hydrogen gas. The device is fabricated in a
layered Pd/i-diamond/p-diamond Schottky diode configuration. Test
results indicate that the technology will allow rapid detection of
hydrogen leaks during fueling operations. The same technology with
modifications can provide a similar capability for detecting
oxygen. The objective of this Phase I project is to develop and
deliver a brassboard hydrogen gas sensor and to develop and
demonstrate in a laboratory setting the capability to detect
gaseous oxygen. The effort proposed includes modification of the
current hydrogen detector to meet NASA requirements, development of
readout/interface circuitry, demonstration/ delivery of the
hydrogen sensor with PC interface in brassboard form, performance
of R&D to modify the design to detect oxygen, and demonstration of
the oxygen detector in a laboratory test. Phase II would take the
combined hydrogen/oxygen sensor to the prototype level. The net
result will be a hydrogen/oxygen sensor meeting NASA requirements
for detection of leaks in the 1-1000 ppm range during fueling
operations.
The diamond chemical sensor can work for either gases or liquids
and operates as a direct electronic device known as a diode. The
device can be modified to detect minute changes in the type and
amount of any of several chemical agents that are in proximity to
the diamond sensor. This causes large changes in the electrical
current which flows through the detector diode. As a result, the
usefulness of this sensor technology is not limited to hydrogen and
oxygen but may be useful in many commercial applications such as
identification of trace amounts of toxins in biological fluids, in-
process control of critical chemical concentrations, continuous and
direct measurement of internal combustion engine noxious emissions,
and direct measurements of low concentrations of gaseous hydrogen
and hydrocarbons for mine safety. The ruggedness of diamond
materials allows use of this detector in environments where no
other device would survive. In addition, various aspects of this
technology make it a strong candidate for the development of
personal warning detectors which could be applied to a broad range
of requirements in the government and private sectors.
Key Words
Physitron, Inc.
3304 Westmill Drive
Huntsville, AL 35805-6132