<title>High-spatial-resolution imaging system for high-energy neutrons in inertial confinement fusion experiments</title>

Abstract

The penumbral imaging technique has proven to be ideally suited for neutron imaging. The French CEA has successfully installed a neutron imaging system at the LLE (Rochester-New York) in June 2000.Images ofthe 14MeV fusion neutrons produced in the target have been recorded in the range 1012 to 1014 with a two-point resolution of 45 micrometers. The detector used was a 1 5cm diameter circular array composed ofplastic scintillator elements. For several ofthe CEA experiments, bubble detectors developed for General Atomics simultaneously recorded neutron images. The SIRINC (Simulation and Reconstruction Imaging Neutron Code) code has been used to unfold neutron images obtained both with the segmented scintillator detector and with the bubble detector. We first describe the experimental setup and detector designs, then compare the sensitivity, quantity of information, and signal to noise ratio for those two detectors. Then raw and unfolded images are presented. The spatial resolution obtained for the unfolded images are estimated and compared for the two detectors types