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Title: Hot spot generation in energetic materials created by long-wavelength infrared radiation

Abstract

Hot spots produced by long-wavelength infrared (LWIR) radiation in an energetic material, crystalline RDX (1,3,5-trinitroperhydro-1,3,5-triazine), were studied by thermal-imaging microscopy. The LWIR source was a CO{sub 2} laser operating in the 28-30 THz range. Hot spot generation was studied using relatively low intensity (∼100 W cm{sup −2}), long-duration (450 ms) LWIR pulses. The hot spots could be produced repeatedly in individual RDX crystals, to investigate the fundamental mechanisms of hot spot generation by LWIR, since the peak hot-spot temperatures were kept to ∼30 K above ambient. Hot spots were generated preferentially beneath RDX crystal planes making oblique angles with the LWIR beam. Surprisingly, hot spots were more prominent when the LWIR wavelength was tuned to be weakly absorbed (absorption depth ∼30 μm) than when the LWIR wavelength was strongly absorbed (absorption depth ∼5 μm). This unexpected effect was explained using a model that accounts for LWIR refraction and RDX thermal conduction. The weakly absorbed LWIR is slightly focused underneath the oblique crystal planes, and it penetrates the RDX crystals more deeply, increasing the likelihood of irradiating RDX defect inclusions that are able to strongly absorb or internally focus the LWIR beam.

Authors:
; ;
Publication Date:
OSTI Identifier:
22283171
Resource Type:
Journal Article
Journal Name:
Applied Physics Letters
Additional Journal Information:
Journal Volume: 104; Journal Issue: 6; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0003-6951
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ABSORPTION; CARBON DIOXIDE LASERS; CRYSTALS; HOT SPOTS; INFRARED RADIATION; MICROSCOPY; REFRACTION; THERMAL CONDUCTION; TRIAZINES; WAVELENGTHS

Citation Formats

Chen, Ming-Wei, You, Sizhu, Suslick, Kenneth S., and Dlott, Dana D., E-mail: dlott@illinois.edu. Hot spot generation in energetic materials created by long-wavelength infrared radiation. United States: N. p., 2014. Web. doi:10.1063/1.4865258.
Chen, Ming-Wei, You, Sizhu, Suslick, Kenneth S., & Dlott, Dana D., E-mail: dlott@illinois.edu. Hot spot generation in energetic materials created by long-wavelength infrared radiation. United States. https://doi.org/10.1063/1.4865258
Chen, Ming-Wei, You, Sizhu, Suslick, Kenneth S., and Dlott, Dana D., E-mail: dlott@illinois.edu. 2014. "Hot spot generation in energetic materials created by long-wavelength infrared radiation". United States. https://doi.org/10.1063/1.4865258.
@article{osti_22283171,
title = {Hot spot generation in energetic materials created by long-wavelength infrared radiation},
author = {Chen, Ming-Wei and You, Sizhu and Suslick, Kenneth S. and Dlott, Dana D., E-mail: dlott@illinois.edu},
abstractNote = {Hot spots produced by long-wavelength infrared (LWIR) radiation in an energetic material, crystalline RDX (1,3,5-trinitroperhydro-1,3,5-triazine), were studied by thermal-imaging microscopy. The LWIR source was a CO{sub 2} laser operating in the 28-30 THz range. Hot spot generation was studied using relatively low intensity (∼100 W cm{sup −2}), long-duration (450 ms) LWIR pulses. The hot spots could be produced repeatedly in individual RDX crystals, to investigate the fundamental mechanisms of hot spot generation by LWIR, since the peak hot-spot temperatures were kept to ∼30 K above ambient. Hot spots were generated preferentially beneath RDX crystal planes making oblique angles with the LWIR beam. Surprisingly, hot spots were more prominent when the LWIR wavelength was tuned to be weakly absorbed (absorption depth ∼30 μm) than when the LWIR wavelength was strongly absorbed (absorption depth ∼5 μm). This unexpected effect was explained using a model that accounts for LWIR refraction and RDX thermal conduction. The weakly absorbed LWIR is slightly focused underneath the oblique crystal planes, and it penetrates the RDX crystals more deeply, increasing the likelihood of irradiating RDX defect inclusions that are able to strongly absorb or internally focus the LWIR beam.},
doi = {10.1063/1.4865258},
url = {https://www.osti.gov/biblio/22283171}, journal = {Applied Physics Letters},
issn = {0003-6951},
number = 6,
volume = 104,
place = {United States},
year = {Mon Feb 10 00:00:00 EST 2014},
month = {Mon Feb 10 00:00:00 EST 2014}
}