Thermal Impulse Sensors for Use in Explosions
Abstract
The United States faces a variety of threats from weapons of mass destruction, including biological agents. The defeat of biological agents such as anthrax spores poses some serious challenges as they are very difficult to destroy. Under controlled conditions, biological agents are destroyed in a furnace by exposing them to high temperatures for certain periods of time. However, in access-denied areas, explosive weapons may need to be used to destroy them. The responsible use of such weapons requires detailed knowledge of their effect and lethality. In particular, the development of weapons capable of destroying biological agents requires knowledge of the thermal impulse (i.e., temperature and heating duration) inside an explosive fireball. Until a few years ago, temperature measurements in explosive fireballs were limited to techniques such as optical pyrometry and spectral line fitting which provide only average temperatures from near the surface of the fireball, as well as thermocouples which are limited in their response time and their ability to withstand the extreme conditions inside an explosive fireball. More recently, a new approach was proposed – seeding the fireball with micrometer or nanometer sized sensors and then performing a post-detonation analysis on these sensors to determine the temperature and heating duration. We have developed some initial temperature sensors for such an approach and have successfully tested them for temperatures between about 250 °C and about 800 °C. In addition, we have developed some initial thermal impulse sensors, capable of measuring temperature and heating duration, and have tested them in the laboratory for temperatures above about 700 °C and for heating times between 2 s and 60 s. The goal of our current work is to provide the Defense Threat Reduction Agency with the capability to reliably measure temperature and heating duration inside the fireball of an explosion. To that end, we are evaluating and modifying our thermal impulse sensors for heating durations as short as 1 ms, and for temperatures between 200 °C and 1000 °C. Once the functionality of these thermal impulse sensors has been verified and the specific optical signatures identified, we will prepare a plan for the design and development of a portable computerized instrument. This instrument will allow trained technicians to perform measurements and analysis of the thermal impulse sensors in the field. At the completion of the base period we expect to have tested a set of calibrated thermal impulse sensors in laboratory- and field-environments, as well as a plan to design and build a portable computerized analysis instrument. At the end of the option period, we expect to have a fully functioning and field-tested portable computerized analysis instrument. These deliverables will provide DTRA with the means to assess, in field environments, the effectiveness of explosives developed for the destruction of biological agents.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- May 26, 2016
- Source ID
- HDTRA11510044
Entities
People
- Hergen Eilers
Organizations
- Defense Threat Reduction Agency
- Washington State University