Evaluation of Nuclear Warhead Symmetry Detection by Compton Camera

Abstract

Compton camera is a promising instrument for nuclear material imaging in arms control scenarios. In planning to build a Compton camera to detect the symmetry of shielded nuclear materials, the energy spectrum of gamma-rays escaping from the Steve Fetter Nuclear Warhead model is obtained using Monte Carlo simulation. Then, a point model is defined for our study. The proposed Compton camera uses a 5-cm × 5-cm × 1-mm double-sided silicon strips detector as the scattering detector and a segmented ϕ5.08 × 5.08-cm NaI(Tl) array as the absorbing detector. How high-energy gamma-rays impact low-energy characteristic gamma-ray imaging is studied. The result shows that high-energy gamma-rays will reduce the imaging accuracy and signal-to-noise ratio. The holistic angle resolution measured can reach 4.15 deg by all characteristic gamma-rays. The symmetry research result shows that the Compton camera can detect the symmetry property of a nuclear warhead with obvious symmetry or asymmetry.

Keywords:

• Compton camera
• gamma-ray imaging
• nonproliferation
• Monte Carlo method
• nuclear security

Acknowledgments

This work was supported by the Foundations for Development of Science and Technology of the China Academy of Engineering Physics under grant 2015B0103007 and the National Natural Science Foundation of China under grants 11605175 and 11375157.