{'fraction_non_alphanumeric': 0.018998272884283247, 'fraction_numerical': 0.0, 'mean_word_length': 4.492890995260663, '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}}
The size-of-source effect in practical measurements of radiance

One of the main sources of error when making precise measurements of radiance is the one associated to the variation in the output signal of the radiometer due to changes in the size of the source. This effect is known as the size-of-source effect (SSE). It is observed experimentally that as the size of the source increases, the output signal of the radiometer increases as well. No standard method for measuring the SSE exists. The SSE is estimated as the ratio of the output signal at a given diameter of the source to the signal at a reference diameter. One method considers this reference diameter as the diameter of an infinite source. A second method sets the reference diameter to the largest diameter experimentally possible. Commonly, the second method is the one used since it is more practical. However, the first one is a better model, even though the limit to infinite is not available experimentally. In this work, we discuss a formal method to calculate this limit. The limit can be used in the first method for a better quantification of the effect in practical measurements.