Flash X-ray photography

Compared to optical photography. X-rays have the distinct advantage that they see through opaque clouds of smoke and debris. Most materials can also be penetrated by the appropriate high-energy X-rays, making internal voids in materials, such as incipient spalls, clearly visible. 

In a dynamic event, one obtains only one X-ray per X-ray head, as opposed to a number of optical photographs taken through a given optical lens. Often several X-ray heads are used to show the evolution of the deformation, but each X-ray views the event from a different angle and it is not uncommon to view the event orthogonally. This can be used to advantage to determine the location of certain features through parallax. For a review on this technique, see Isbell (1987). 

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Hulling, L., Zhengping, H, and Jing, B. Displacement Gradient Method for Measuring Detonation Parameters Using Flash X-Ray Photography, Proc. 8th Symposium (International) on Detonation, NSWC MP 86-194, Albuquerque, NM, 1985, pp. 440-446. 

Determination of the Detonation Wave Parameters Using Flash X-Ray Photography... 

The diagnostics applied to shock experiments can be characterized as either prompt or delayed. Prompt instrumentation measures shock velocity, particle velocity, stress history, or temperature during the initial few shock transits of the specimen, and leads to the basic equation of state information on the specimen material. Delayed instrumentation includes optical photography and flash X-rays of shock-compression events, as well as post-mortem examinations of shock-produced craters and soft-recovered debris material. 

When a visible light flash cannot be applied because extreme lighting obliterates the effect under study, one resorts to " X- Ray Photography , also known as "Radiography of High Speed Event . It is briefly described on pC17-R of Vol 2. 

Hewitt GF, DN Roberts. Studies of Two-Phase Flow Patterns by X-Ray and Flash Photography. Report AERE-M 2159. London HMSO, 1969. 

Hewitt, G.F. and Roberts, D.N., Studies of two-phase flow patterns by simultaneous X-ray and flash photography. Report AERE-M 2159. London, HMSO (1969). 

These X-ray flashes are an important means of short-time photography because they enable fast occuring phenomena to be recorded by means of X-ray photographs. 

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