Mapping Boron Dioxide (BO2) Light Emission During Ballistic Initiation of Boron
Technical Report,01 Feb 2013,28 Feb 2015
US Army Research Laboratory Aberdeen Proving Ground, United States
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This work describes chemical imaging of boron dioxide BO2 formed during ballistic initiation of 11 by weight powder-mixtures of boron B and potassium nitrate KNO3 contained within a polyethylene spherical projectile 25-mm diameter. Initiation was achieved by impact of the gas-gun-launched BKNO3-filled projectile with an anvil in a windowed, air-filled chamber. To monitor the subsequent chemical reaction, a 2-camera, optically filtered method to map discrete chemical emission from the BO2 molecule was used. This technique distinguishes incandescence of hot particles produced during the event from discrete chemical emission by BO2 near a wavelength of 546 nm. The dependence of delay in BO2 chemical emission that exceeded particle incandescence with impact velocity was investigated, and chemical emission movies, which ratio the intensity of discrete to thermal emission, are discussed. Emission spectra 300- to 1000-nm wavelength were recorded during the impact event and used to determine a gray-body temperature of the hot particles during the time when BO2 emission was most intense.