Design of tomographic diagnostic system for Indian Test Facility (INTF) neutral beam injector

A non-invasive diagnostic technique based on tomographic reconstruction has been developed for the design optimisation of tomographic diagnostic system to be used in Indian Test Facility (INTF) neutral beam injector. The technique uses measured line integrated value of optical emissions from the beam particles using an optical detection system. The 2D spatial profile of the beam can be obtained from the tomographic inversion of the line integrated emission data. The inversion technique often constitutes an underdetermined problem because of the restricted viewing port available for installing sufficient detectors, making it difficult for direct inversion without invoking any suitable constraint. For obtaining the 2D emission profile of such a system, a tomography algorithm taking "maximum entropy" concept has been developed. The detailed theory of the algorithm and its application in INTF is presented. A suitable detection system, its components and features to obtain the line integrated data is also discussed. The quality of reconstruction of the algorithm is tested for different detector configurations. Reconstructions after adding noise to the detector signals are also obtained. An error analysis for all the reconstructions is studied and based on that the number of detectors for complete reconstruction of the beam is optimised.