Role of sandwich holography in inertial confinement fusion

At KMS Fusion we have adapted the technique of Sandwich Holography to characterize cryogenic targets used in inertial confinement fusion (ICF). The procedure allows us to expose a holographic film at a given moment and later (minutes, hours, days) expose a second plate. On reconstruction of the two images, we have a holographic interferogram of any change of state of the fuel. This means that on large ICF target chambers, in spite of vibration and thermal induced motions, it is possible to characterize cryogenic targets. The technique also holds great promise for observing the fuel layers produced in beta heating experiments now in progress. In these experiments it can be minutes to days between the required exposures. A micropositioner is necessary for interferometric reconstruction, since indexing of the order of a wavelength of light is required to interpret the resulting fringe pattern. The procedure and some practical applications are discussed in the paper