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A sheathed silicon optical fiber probe was used to observe the radiance in explosive combustions. The utility of such probes was demonstrated by placing them both inside and in the vicinity of the explosion's fireball. H-6 composition (100 g of RDX/TNT, 60:40 ratio mixed with aluminum) was used. It was shown that the probes were capable of surviving the hostile environment in the presence of shock waves and temperatures (2,000 - 3,000 degrees Celsius) beyond the melting point of silicon glass. This paper describes the use of a light pipe radiometer consisting of a silicon optical fiber cable which has a core/outer diameter of 62.5/125 micrometer and the steel conduit (20 mm diameter) that was used to firmly hold it. The advantages of such a probe are that it allows the use of very high speed photodetectors (InGaAs PIN photodetector, with bandwidth of 10 kHz - 125 MHz, rise time 3 ns and operating wavelengths in the range of 800 - 1800 micrometer). The low cost, readily available probe was insensitive to pressure and has a very high resistance to the effects of shock waves. This device provides a radiant measurement technique that can be applied in situations where cameras can neither reach, nor afford to be destroyed. The disadvantage is that the fiber facet may become coated by opaque combustion products which tend to interfere with the radiant reading. This technique is particularly suitable for cross examination of explosive combustion where a number of such probes are employed in an array. It can also be used to monitor the presence of burning particles within defeated armours and hence via their irradiance, to determine the danger to personnel.
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