Question: who invented the hot cathode x ray tube
[{'answer': 'William Coolidge', 'provenance': [{'wikipedia_id': '907899', 'title': 'X-ray tube', 'start_paragraph_id': 4, 'start_character': 283, 'end_paragraph_id': 4, 'end_character': 299, 'bleu_score': 1.0, 'section': 'Section::::History.\n'}]}, {'provenance': [{'wikipedia_id': '907899', 'title': 'X-ray tube', 'start_paragraph_id': 4, 'start_character': 249, 'end_paragraph_id': 4, 'end_character': 448, 'bleu_score': 0.9466178497997021, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 11546189395904859282}, 'section': 'Section::::History.\n'}]}]