Abstract: A clamp for positioning a photocell adjacent to an ultraviolet light source including: a housing sized and shaped to receive at least a portion of the photocell; a seal positioned about conductive members extending from the photocell and out of the housing against penetration of liquids into the housing; another seal connected to the housing and having an access opening to a detection end of the photocell; and spaced apart opposed arms extending from the housing and having portions sized and shaped to firmly receive an outer surface of the ultraviolet light source, wherein the detection end of the photocell is positioned at a predetermined distance from the light source.

Abstract: A submersible photocell for detecting ultraviolet light in disinfection apparatus including a quartz jacket capable of transmitting ultraviolet light and a fluorescent material sensitive to ultraviolet light at a wavelength of about 253.7 nm and which produces an infrared secondary emission having a wavelength of about 730-735 nm upon absorption of ultraviolet light. The photocell also includes a photoconductor sensitive to the secondary emission light, is located adjacent the fluorescent material and is capable of varying conductance of electricity upon absorbing light having a wavelength of about 730-735 nm from the infrared secondary emission. The photocell further includes electrically conductive wiring connected to the photoconductor and extending outwardly of the jacket at its remote end.