Definition of actinometer in US English:



  • An instrument for measuring the intensity of radiation, especially ultraviolet radiation.

    • ‘After the monochromator the light was reimaged onto the actinometer and a silicon photodiode, located behind the cuvette, by a normal-incidence spherical mirror as indicated in Fig.1.’
    • ‘Porrino et al using an instrument designed at the NIMH called the actinometer found that a 15 mg dose of DAS would produce a decrease in hyperactive motor behavior for 8 hours.’
    • ‘Chemical actinometry using the potassium ferrioxalate actinometer gave an incident intensity 10 of about 2.8 X 10 + 16 quanta-s 1.’
    • ‘Second, to measure the number of moles of photons or einsteins absorbed by the actinometer, a calibrated system must be used, which can be either another actinometric solution or a calibrated radiometer, photocell or photodiode.’
    • ‘Spherical and tubular actinometers containing iodide/iodate solution were suspended from the ceiling at the positions indicated in Fig.1.’


Mid 19th century: from Greek aktis, aktin- ‘ray’ + -meter.