Assessment of the total radiant power or luminous flux of light sources using integrating spheres is one of the most important tests in light measurement. The inside surface of an integrating sphere is coated with a diffusely reflecting material which guarantees complete integration and homogenization of the emitted radiation. The integrated light is then measured at the detector port.
Instrument Systems has developed a complete series of integrating spheres, available in a wide range of sizes and providing functionality for a broad spectrum of applications. A deciding factor in choosing the appropriate integrating sphere is the maximum dimension of the light source to be measured. Larger sources require the use of larger integrating spheres in order to keep measurement errors to a minimum.
All integrating spheres have a side entrance port for determining luminous flux in the 2π configuration (i.e. for determining emission into the forward hemisphere only). With the larger integrating spheres, the test object can also be mounted in the center, thus permitting measurements in the 4π configuration (i.e. for determining emission in all directions).
The latest integrating spheres are specifically designed for measuring UV sources. They use polytetrafluoroethylene (PTFE) which is highly reflective in the UV spectral range down to 200 nm. It therefore allows high throughput, even for challenging UV-B and UV-C emitters. In combination with the proven CAS array spectroradiometers reliable and precise UV measurements are guaranteed.