Transition radiation detector

Transition radiation detectors (English Transition Radiation Detector TRD short ) are particle detectors that use the object created by the interface of two media with different dielectric constants in the passage of charged particles of highly relativistic transition radiation to determine the identity of the particle.

Operation

Transition radiation is used in particle physics for the detection and identification of high-energy particles (particularly electrons and hadrons ) from energies of about 1 GeV.

By the linear function of the radiation intensity of the Lorentz factor particle can be at a known ( otherwise specific ) to the particle mass and thus deduce the identity of the particle.

Since the radiation intensity per interface is very low ( in a typical configuration is detectable for a particle with an average much less than one photon ) are usually realized many transitions by the detector is built up in layers of thin films of different dielectric constants. The film stack are usually perpendicular to the direction of the Teilchendurchgangs. The periodic arrangement may also make use interference phenomena. The increase in intensity by increasing the film speed is set by the self- absorption of transition radiation limits. That form on the radiator foil X-ray photons are usually detected using gas detectors (eg multi-wire chambers or MPGD ), which are located either behind the film arrangement or are sandwiched integrated into the film stack.

Use

Transition radiation detectors are used for example in some LHC experiments to distinguish between electrons and hadrons (especially: pions ) use. So the ATLAS TRD the electron / pion separation is energy 1-100 GeV, the ALICE TRD covers the energy range 1-6 GeV from.

In astroparticle transition radiation detectors are used for example in the AMS and CREAM experiments.

Swell

• Particle