Abstract: A process for measuring transmittance of a fluid with first and second radiation wavelengths includes (i) positioning a polychromatic radiation source and a polychromatic radiation sensor in a spaced relationship to define a first thickness of fluid; (ii) detecting a first radiation intensity corresponding to the first wavelength at the first thickness; (iii) detecting a second radiation intensity corresponding to the second wavelength at the first thickness; (iv) altering the first thickness to define a second thickness; (v) detecting a third radiation intensity corresponding to the first wavelength at the second thickness; (vi) detecting a fourth radiation intensity corresponding to the second wavelength at the second thickness; and (vii) calculating radiation transmittance of the fluid in the radiation field from the first radiation intensity, the second radiation intensity, the third radiation intensity and the fourth radiation intensity.

Abstract: There is disclosed a process for measuring transmittance of a fluid in a radiation field comprising polychromatic radiation—i.e., radiation at a first wavelength and radiation at a second wavelength different from the first wavelength.

Abstract: An optical radiation sensor device for detecting radiation in a radiation field having a thickness. A preferred embodiment of the device includes a radiation source and a radiation sensor element positioned to receive radiation from the radiation source. A motor (or other motive means) is provided to alter the thickness of the radiation field from a first thickness to a second thickness. The sensor element is capable of detecting and responding to incident radiation from radiation source at the first thickness and at the second thickness. The optical radiation sensor device allows for determination of radiation (preferably ultraviolet radiation) transmittance of a fluid of interest.

Abstract: An optical radiation sensor device for detecting radiation in a radiation field having a thickness. A preferred embodiment of the device includes a radiation source and a radiation sensor element positioned to receive radiation from the radiation source. A motor (or other motive means) is provided to alter the thickness of the radiation field from a first thickness to a second thickness. The sensor element is capable of detecting and responding to incident radiation from radiation source at the first thickness and at the second thickness. The optical radiation sensor device allows for determination of radiation (preferably ultraviolet radiation) transmittance of a fluid of interest.

Abstract: An optical radiation sensor device for detecting radiation in a radiation field having a thickness. A preferred embodiment of the device includes a radiation source and a radiation sensor element positioned to receive radiation from the radiation source. A motor (or other motive means) is provided to alter the thickness of the radiation field from a first thickness to a second thickness. The sensor element is capable of detecting and responding to incident radiation from radiation source at the first thickness and at the second thickness. The optical radiation sensor device allows for determination of radiation (preferably ultraviolet radiation) transmittance of a fluid of interest.