Distribution and Radiation Method for Measuring the Ultraviolet Radiation Flux 1: Definition and Characteristics of Ultraviolet Radiation

Abstract: In recent years, with more and more attention is paid to the UV light source, people attach more importance to the evaluation. The total radiation flux is one of the most important technology indexes of UV light source. This paper describes the basic principle and method of using the distribution Spectrophotometer to measure the flux of ultraviolet radiation flux, analyzes and discusses the ultraviolet detector cosine fixed problem.

Keywords: ultraviolet radiation; radiant flux; ultraviolet power

Ultraviolet radiation is the optical radiation of the wavelength range between 10～400nm. In this wavelength range, the ultraviolet with different wavelength has different effect. In the process of research and application, ultraviolet is often divided into the following parts: UV-A（400～320nm）; UV-B（320～280nm）; UV-C （280～200nm）; vacuum ultraviolet band (200～10nm). Ultraviolet radiation with less than 200nm wavelength can not spread in the air because of the atmospheric absorption.

The development and application of uv light source is in a high speed development period, the constant research and development of the uv light source gradually fills the light source variety blank of each ultraviolet wave band. A series of different types of ultravoilet product includes ultraviolet mercury lamp, ultraviolet metal halide lamp, ultraviolet fluorescent lamp, xenon lamp and other ultraviolet light source.

A remarkable characteristic of the ultraviolet ray is that it has the biological effects.

Physiological changes will happen when human body or other organism is irradiated by the ultraviolet ray. For example, when human body is irradiated by the ultraviolet ray, the skin will produce pigmentation and get darkened.  The bacterium will die soon after the irradiation of the shortwave. Human body will strengthen the disease-resistant ability after the irradiation of a certain wavelengths of the ultraviolet, skin regeneration will be strengthened, and hair growth speed will also be quickened, etc. Especially the short wave (peak wavelength λ = 253.7 nm) uv light source has a strong biological effect, and has the characteristics of no pollution, convenient use, and energy saving etc. So whatever international or domestic biology, medicine, sanitation and epidemic prevention department widely use the radiation source for the wavelength disinfection and sterilization.

At present, uv light source usually uses the ultraviolet irradiation meter to test a surface radiation (unit: W/m2) to represent the ultraviolet intensity of the ultraviolet light source. In the application of air sterilization, water treatment and photochemical reaction, it is more important to know the certain scope (solid angle) of uv radiation flux, and even the ultraviolet radiation intensity size of the whole space, which is usually represented by the uv radiation fluxes. There are two kinds of methods to test the radiation flux of the ultraviolet light source.

The radiation flux of the measured lamp is measured out by comparing the standard lamp of the known radiation flux with the measured lamp within the integrating sphere. Because the Integrating sphere wall coating has absorbed the ultraviolet ray, the ultraviolet reflectance of the coating is low. In addition, excited by the ultraviolet radiation, organic solvents and glue in the coatings will produce the fluorescence effect, therefore the integrating sphere coating must use a special ultraviolet diffuse material of high reflection. Another method is to use distribution meter to measure the radiation flux of the measured light source in each direction. The former method is simple, but the measurement accuracy is less than the latter. So this paper tells a measuring method based on the distribution radiation, namely the distribution radiation method.

Tags：Ultraviolet Radiation , UV Light , UV Radiation Flux