Wavelength shifter
Is referred to as a wavelength shifter, fluorescent materials that absorb photons and emit higher-frequency low-frequency photons.
Introduction
In a wavelength shifter, a high-energy photon is absorbed and emitted more low -energy photons in many cases. The emission of photons is usually done immediately with relaxation times in the nanosecond range. Frequently used wavelength shifter in organic scintillators are POPOP, and 1,4- bis (2- methylstyryl ) benzene (bis- MSB).
These materials are used eg in the calorimeters in particle physics experiments for basic research ( for example, in experiments at DESY ), but they also find application in other material and technical areas, such as the efficiency of photovoltaic cells ( solar cells) to increase.
Others
Also special magnets in the electron storage ring BESSY as plants that are needed for the production of short-wave synchrotron, simplistically referred to as wavelength shifter.