High Repetition Rate and Broadband Mid Infrared Spectroscopy of Post-Detonation Fireball with Novel Laser Sources
Abstract
This is a proposal to characterize post-detonation fireballs using novel laser sources and spectroscopic techniques in the mid-infrared (MIR) spectral region. Characterization of fireballs involving agent defeat additives and chemical agent simulants is needed to determine the efficacy of operations to destroy chemical and biological weapons and their precursors. A better fundamental understanding of the dynamic physical and chemical processes that occur inside the expanding and optically dense fireball will aid predictive models and efforts to determine the effects of different fireballs on chemical and biological weapons. Key diagnostic capabilities include the identification of multiple chemical species and their concentrations during the rapid fireball expansion to provide knowledge of combustion dynamics and temperature fields, and ultimately the lethality of detonations on chemical weapons. Characterization of the fireball on time scales of microseconds is needed to ensure elevated temperatures are attained for the defeat of hazardous materials. Optically based diagnostic techniques are robust in the high temperature and pressure environment of fireballs, and can provide time-resolved species identification and concentration measurements. However, monitoring emission of the intense fireball is ultimately limited to measuring its outer edges at early times due to its optical thickness. This can mask the dynamic chemical processes in its interior, and the intense continuum emission can further obscure critical spectroscopic information. They may however be penetrable in the MIR using high power coherent laser sources for absorption-based spectroscopy, which has largely been under explored due to a lack of suitable laser sources. Broadband absorption spectroscopy in the MIR has the potential to probe inside fireballs and identify key molecular fingerprints even in the presence of continuum emission. In this work, we will utilize high power and broadband MIR fiber laser frequency combs and time-resolved absorption spectroscopy techniques to penetrate and probe the fireball interior on microsecond timescales
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 10, 2017
- Source ID
- HDTRA11710030
Entities
People
- Jason C. Jones
Organizations
- Defense Threat Reduction Agency
- University of Arizona