fall time

https://doi.org/10.1351/goldbook.F02318
See:
response time (of a radiation detector)
Source:
PAC, 1995, 67, 1745. (Nomenclature, symbols, units and their usage in spectrochemical analysis-XI. Detection of radiation (IUPAC Recommendations 1995)) on page 1751 [Terms] [Paper]
See also:
PAC, 1990, 62, 2167. (Glossary of atmospheric chemistry terms (Recommendations 1990)) on page 2174 [Terms] [Paper]