Transitional radiation detector

Transition radiation detectors (engl. Transition Radiation Detector, short TRD) are particle detectors , the, during the passage of charged highly relativistic particles through the interface between two media with different dielectric constants resulting transition radiation use to determine the identity of the particles. ${\displaystyle \varepsilon }$

functionality

Transition radiation is used in elementary particle physics to detect and identify high-energy particles (especially electrons and hadrons) from energies of around 1  GeV .

The linear dependence of the radiation intensity on the Lorentz factor allows conclusions to be drawn about the particle mass and thus the identity of the particle if the particle energy is known (otherwise determined). ${\displaystyle \gamma ={\tfrac {E}{mc^{2}}}}$

Since the radiation intensity per interface is very low (in a typical configuration, a particle with on average far less than one photon can be detected), many transitions are usually implemented by building up the detector in layers from thin foils with different dielectric constants. The film stacks are usually perpendicular to the direction of particle passage. Due to the periodic arrangement, interference phenomena can also be used. The increase in intensity by increasing the number of foils is limited by the self-absorption of the transitional radiation. The X-ray photons generated on the radiator foils are usually detected with the aid of gas detectors (e.g. multi- wire chambers or MPGD ), which are either located behind the foil arrangement or are integrated into the foil stack in a sandwich-like manner. ${\displaystyle \gamma =1000}$

commitment

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

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

swell

1. ↑ Jochen Schnapka: Double track detection using the cathode readout on the ZEUS transition radiation detector. Archived from the original on June 26, 2007. Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. In: Bonn University (Ed.): Diploma thesis University of Bonn . October 1998. Retrieved March 16, 2008.  
2. ↑ Frank Hagenbuck: Development of a novel imaging method for digital subtraction radiography with transition radiation at the Mainz microtron MAMI . In: Mainz University (Hrsg.): PhD Johannes Gutenberg University Mainz . March 2002.
3. ↑ AMS TRD , login required
4. ↑ CREAM