Abstract: A diagnostic apparatus includes a measurement head, a translating calibration element, and a calibration element actuator. The measurement head includes a diagnostic light source, a light sensor, and a measurement head body. The diagnostic light source operates at a diagnostic wavelength ?D and the measurement head body supports the diagnostic light source and the light sensor in a spaced apart relationship across a target fluid passageway to define a diagnostic light path extending from the diagnostic light source to the light sensor. The translating calibration element is partially transparent to light at the diagnostic wavelength ?D and the calibration element actuator is structurally configured to move the translating calibration element into and out of the target fluid passageway. A size and geometry of the translating calibration element is such that the translating calibration element occupies a substantial entirety of the diagnostic light path when moved into the target fluid passageway.

Abstract: A diagnostic apparatus includes a measurement head, a translating calibration element, and a calibration element actuator. The measurement head includes a diagnostic light source, a light sensor, and a measurement head body. The diagnostic light source operates at a diagnostic wavelength ?D and the measurement head body supports the diagnostic light source and the light sensor in a spaced apart relationship across a target fluid passageway to define a diagnostic light path extending from the diagnostic light source to the light sensor. The translating calibration element is partially transparent to light at the diagnostic wavelength ?D and the calibration element actuator is structurally configured to move the translating calibration element into and out of the target fluid passageway. A size and geometry of the translating calibration element is such that the translating calibration element occupies a substantial entirety of the diagnostic light path when moved into the target fluid passageway.

Abstract: Methods and systems for inactivating Desulfovibrio desulfuricans in a fracturing fluid are disclosed. The methods include exposing the fracturing fluid to a dose of from about 4 mJ/cm2 to about 10 mJ/cm2 of polychromatic ultraviolet radiation. The polychromatic ultraviolet radiation includes a plurality of major inactivation wavelength peaks in a range of from about 200 nm to about 400 nm. The system includes an ultraviolet radiation chamber in fluid communication with a fracturing fluid source and a wellbore, and at least one medium pressure ultraviolet lamp arranged substantially within the ultraviolet radiation chamber. The medium pressure ultraviolet lamp exposes the fracturing fluid containing the Desulfovibrio desulfuricans to a dose of from about 4 mJ/cm2 to about 10 mJ/cm2 of polychromatic ultraviolet radiation.