Moll thermopile
From Glossary of Meteorology
A thermopile used in some types of radiation instruments.
Alternate junctions of series-connected manganan–constantan thermocouples are embedded in a shielded nonconducting plate having a large heat capacity. The remaining junctions, which are blackened, are exposed directly to the radiation. The voltage developed by the thermocouple is proportional to the intensity of radiation.
See solarimeter.