THz transmission spectroscopy and imaging: application to the energetic materials PBX 9501 and PBX 9502.

We report the measurement of the effective complex index of refraction near 1 THz for the Plastic-Bonded eXplosives PBX 9501 and PBX 9502. These plastic-bonded explosives consist of organic crystalline energetic materials, HMX and TATB, embedded in a binder matrix. We find that they are partially transparent at a few hundred GHz and we have applied a two-dimensional imaging technique for the detection of pre-fabricated defects in small samples.