Analysis of the backscatter edges on nToF data from NIF

An important metric on a shot at the National Ignition Facility (NIF) is the uniformity of the compression of the capsule. In order to obtain information on the areal density (rhoR) distribution multiple diagnostics are being used: neutron activation diagnostics obtain an intensity profile at many different locations, while neutron Time-of-Flight (nToF) is used to obtain a down scattered ratio on four lines-of-sight. While the downscattered ratio measures the rhoR of the shell for small angle scattering towards the detector, the backscatter edges for (n,d) and (n,t) elastic scattering provide insight to the rhoR at the opposite side of the detector and could therefore be used to improve the angular coverage of the nToF detectors. The analysis of those backscatter edges from nToF data on the NIF will be discussed.