attenuation

https://doi.org/10.1351/goldbook.A00515
The reduction of a radiation quantity upon passage of radiation through matter resulting from interactions of the radiation with the matter it traverses.
Source:
PAC, 1982, 54, 1533. 'Glossary of terms used in nuclear analytical chemistry (Provisional)' on page 1536 (https://doi.org/10.1351/pac198254081533)