A hollow sphere having a highly reflecting inside surface used as a device to collect,
with very high efficiency, light scattered or emitted from a sample contained in it
or located outside and near one of the ports. Small ports allow the entrance of light
and access to a detector.
Source:
PAC, 1996, 68, 2223
(Glossary of terms used in photochemistry (IUPAC Recommendations 1996))
on page 2248