Finding the “lost-time” in detonator function

Journal Article · Wed Mar 13 00:00:00 EDT 2019 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.5088606· OSTI ID:1511626

Smilowitz, Laura Beth  ^[1]; Remelius, Dennis Keith  ^[1]; Suvorova, Natalya Alexandra ^[1]; Bowlan, Pamela Renee  ^[1]; Oschwald, David M. ^[1]; Henson, Bryan Faye  ^[1]

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1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Exploding bridgewire (EBW) detonators were invented during the Manhattan Project over 75 years ago. Initially developed for precise timing and reproducibility, they continue to be used in many applications. Despite widespread use and reliability, their mechanism for function remains controversial. They provide precision timing, yet their function is described in terms of a “lost time” accounting for nearly half of the function time. Buried in understanding the EBW function is the mystery of how an incoherent impulse such as powering a bridgewire yields the coherent energy output of a detonation. Even the general phenomena by which release of chemical energy in a crystalline organic explosive becomes associated with the sonic plane of a steady detonation wave remain uncertain. Here, we investigate the EBW function with a suite of diagnostics and show that stationary heating occurs during the “lost-time.” We use x-ray radiography to observe the propagation of a shock wave from bridgewire vaporization and establish that the origin of the radially emanating detonation wave is spatially separated from the initial shock. Utilizing the observed temperature as a boundary condition in our explosive response models yields a thermal ignition consistent with the “lost-time” and detonation location consistent with previous work. With these findings, we define a direct thermal initiation mechanism for the EBW function consistent with previous integral observations and explain the displacement of initiation from the bridgewire burst in time and space.

• Research Organization: Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: 89233218CNA000001
• OSTI ID: 1511626
• Report Number(s): LA-UR-18-31794
• Journal Information: Applied Physics Letters, Vol. 114, Issue 10; ISSN 0003-6951
• Publisher: American Institute of Physics (AIP)
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
detonator