Source characterization and modeling development for monoenergetic-proton radiography experiments on OMEGA

作者：Manuel M J E^*; Zylstra A B; Rinderknecht H G; Casey D T; Rosenberg M J; Sinenian N; Li C K; Frenje J A; Seguin F H; Petrasso R D

来源：Review of Scientific Instruments, 2012, 83(6): 063506.

DOI：10.1063/1.4730336

A monoenergetic proton source has been characterized and a modeling tool developed for proton radiography experiments at the OMEGA [T. R. Boehly et al., Opt. Comm. 133, 495 (1997)] laser facility. Multiple diagnostics were fielded to measure global isotropy levels in proton fluence and images of the proton source itself provided information on local uniformity relevant to proton radiography experiments. Global fluence uniformity was assessed by multiple yield diagnostics and deviations were calculated to be similar to 16% and similar to 26% of the mean for DD and (DHe)-He-3 fusion protons, respectively. From individual fluence images, it was found that the angular frequencies of greater than or similar to 50 rad(-1) contributed less than a few percent to local nonuniformity levels. A model was constructed using the Geant4 [S. Agostinelli et al., Nuc. Inst. Meth. A 506, 250 (2003)] framework to simulate proton radiography experiments. The simulation implements realistic source parameters and various target geometries. The model was benchmarked with the radiographs of cold-matter targets to within experimental accuracy. To validate the use of this code, the cold-matter approximation for the scattering of fusion protons in plasma is discussed using a typical laser-foil experiment as an example case. It is shown that an analytic cold-matter approximation is accurate to within less than or similar to 10% of the analytic plasma model in the example scenario.

• 出版日期2012-6