A comparison of four reconstruction methods for JET neutron and gamma tomography

The JET neutron profile monitor coverage of the neutron/gamma emissive region enables tomographic reconstruction. However, due to the availability of only two projection angles and to the coarse sampling, tomography is a highly limited data set problem. A comparative study concerning the applicability to JET tomography of four methods—maximum likelihood, maximum entropy, Tikhonov regularization and a Monte Carlo back-projection algorithm—is reported. The methods have been tested on numerically simulated phantoms with shapes characteristic for this kind of tomography. The retrieval of sophisticated structures in the emissive distribution has been addressed in order to have a complete image of the quality and reliability of the methods. A both qualitative and quantitative evaluation is reported.