Fast Camera Enhances Understanding of High Explosive Detonation

Specialised Imaging has released a new application note that describes how its SIM8 ultra fast camera offers the capability to capture and diagnose the process of detonation of high explosive driven liner.

The development of short-duration electrical-pulse detonators such as the exploding bridge wire (EBW) allows initiation of secondary explosives to be done with a higher level of safety, repeatability and reliability than is achievable with hot wire detonators. With the development of such detonation systems, diagnostic techniques capable of accurately characterising detonator functionality are required.

Application note 14 describes how a SIM8 Ultra Fast Camera running at 1 million frames per second (1360 x 1040 pixels per frame) with 500 ns exposures and front lighting was used to record the detonation of high explosive driven liner using a EBW detonator. Initial timing for the detonator and camera were generated using timing from digital delay generators. Additional synchronization of precise delays to start of frames and flashes were achieved using internal camera timing generators with nanosecond accuracy. Framing data is presented covering the 7.5 s recording period of interest enabling clear diagnosis of how the high explosive driven liner detonates.

Crucial for ultra fast events such as explosive detonation the optical design of the SIM8 provides the choice of up to 8 separate optical channels without compromising performance or image quality. Effects such as parallax and shading, inherent in other ultra fast framing cameras, are eliminated and the high spatial resolution (> 50 lp/mm) is the same from frame to frame and in both axes. Individual ultra-high resolution intensified CCD detectors, controlled by state-of-the-art electronics, offer almost infinite control over gain and exposure allowing researchers total freedom to capture images of even the most difficult transient phenomena.

A copy of Application Note 14 may be downloaded from http://www.specialised-imaging.com/apps_and_results.php.