{'fraction_non_alphanumeric': 0.04365079365079365, 'fraction_numerical': 0.001984126984126984, 'mean_word_length': 5.0843373493975905, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Ultra-Low-Emittance Light Sources

In this special issue, we delve into the subject of ultra-low-emittance storage ring light sources. While these go under various names, such as “diffraction-limited storage rings” and “ultimate storage rings,” perhaps the most universally applicable name is “fourth-generation storage rings” or 4GSRs. As this name suggests, these rings promise improvements in X-ray brightness that are comparable to those seen in the transition from second- to third-generation rings.