Question: What American engineer and physicist taught at Princeton University and Massachusetts Institute of Technology and developed one of the first million-volt X-ray generators with John G. Trump?
{'answer': 'Robert J. Van de Graaff', 'supporting_facts': [['John G. Trump', 0], ['John G. Trump', 3], ['Robert J. Van de Graaff', 0], ['Robert J. Van de Graaff', 1]]}