An overview ofthe radiographic capabilities with emphasis on electronic image detection and processing at the Los Alamos National Laboratory is presented. Fixed facilities and portable x-ray sources and imaging systems make up the Los Alamos capability. Examples of imaging with large area amorphous silicon imaging panels, a portable computed tomography system, high speed x-ray imaging applications and equipment, and small area, high resolution imagers are given. Radiographic simulation and reverse engineering from radiographic images to computer aided design files and solid models is also presented.
Time-resolved radiography is the creation of an x-ray image for which both the start-exposure and stop-exposure times are known with respect to the event under study. The combination of image and timing are used to derive information about the event. We have applied time-resolved radiography to evaluate motions of explosive-driven events.In the particular application discussed here, our intent is to measure maximum deflections of the components involved. Exposures are made during the time just before to just after the event of interest occurs. A smear or blur of motion out to its furthest extent is recorded on the image.Comparision of the dynamic images with static images allows deflection measurements to be made.
TIME-RESOLVED RADIOGRAPHYThe concept of time-resolved radiography (TRR) is outlined in the following steps.a) The subject is continuously irradiated with x-rays to form an image on a suitably fast phosphor screen placed behind the subject. (The continuous xray source actually needs only to be stably on during the exposure period.)b) The phosphor screen is viewed by a gated camera. c) A trigger signal is available to indicate the start of the event.d) The camera gate is opened for a selected duration exposure after a selected delay following the trigger.The basic idea is to acquire an image over a selected period of time known with respect to the event of interest.
Cineradiography and TRRCineradiography is a subset of TRR in that a contiguousseries of images are acquired within the time frame of an event and is connoted with stop-action imaging.Image converter cameras are commercially available which place 5 to 20 images on one film at rates up to 600 Mframes/sec. The camera output can also be digitized by a still video system.The highest rates available for video radiography are 2 kframes/sec at 192x240 pixel resolution or 12 kframes/sec at 64x64 pixels. Many times specialized systems are built using multiple cameras to achieve ultra-high frame rates. These multi-camera systems are limited to 270 / SPIE Vol. 1346 Ultrahigh-and High-Speed Photography, Videography, Photonics, and Velocimetry '90 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 06/23/2016 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx
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