Imaging with penetrating radiation for the study of small dynamic physical processes. (14th May 2015) - Merrill, F. E.
Abstract Since Roentgen's discovery of X rays in the late 1800s the use of penetrating radiation to form images has become a part of our everyday life as well as providing a useful tool for the scientific study of processes that have been previously impossible to measure. This can include the study of processes that are too deeply embedded in opaque materials for direct observation, or that occur on a length or time scale smaller than otherwise can be easily measured. As technologies to generate penetrating radiation and quickly collect images have matured, new techniques have emerged to measure processes that have been hidden for many years. One example is advances in flash radiography using charged particles as radiographic probes, including proton radiography and electron radiography. Recently the successful commissioning of proton microscope systems has provided remarkable improvements in spatial resolution. These techniques are being implemented for applications with electron radiography. With the evolution of these new techniques comes the opportunity to choose the probe that provides the maximum information for the desired measurement. This paper describes these new imaging techniques, predicts the capabilities of high-energy electron radiography, and provides a guide for identifying the optimal probe for a wide range of measurements.