Proceedings Article | 29 August 2009
KEYWORDS: Waveguides, Silicon, NOx, Infrared spectroscopy, Microscopes, Data modeling, Sensors, Nondestructive evaluation, Fiber optics, Modulation
Hexanitrostilbene (HNS) is a secondary explosive widely used in a variety of commercial and military applications, due
in part to its high heat resistivity. Degradation of HNS is known to occur through exposure to a variety of sources
including heat, UV radiation, and certain chemical compounds, all of which may lead to reduced performance.
Detecting the degradation of HNS within a device, however, has required destructive analyses of the entire device while
probing the HNS in only an indirect fashion. Specifically, the common methods of investigating this degradation include
wet chemical, surface area and performance testing of the devices incorporating HNS rather than a direct interrogation of
the material itself. For example, chemical tests frequently utilized, such as volatility, conductivity, and contaminant
trapping, provide information on contaminants present in the system rather than the chemical stability of the HNS. To
instead probe the material directly, we have pursued the use of optical methods, in particular infrared (IR) spectroscopy,
in order to assess changes within the HNS itself. In addition, by successfully implementing miniature silicon (Si)
waveguides fabricated at Sandia National Laboratories to facilitate this spectroscopic approach, we have demonstrated
that HNS degradation monitoring may take place in a non-destructive, in-situ fashion. Furthermore, as these waveguides
may be manufactured in a variety of configurations, this direct, non-destructive, approach holds promise for
incorporation into a variety of devices.
