Particle detector

A particle detector is a device or instrument for detecting free, moving molecules, atoms or elementary particles. Since particles with very different properties can be detected with particle, there are many different particles and radiation detectors with different operating principles. For most detectors, the incident particles are registered as individual events; the average number of events per unit time is then called count rate.

Proof of electromagnetic interaction with matter

Gas-filled ionization detectors

  • Ionization chamber: Here, the electrical charge generated by ionizing radiation is measured either as a single current pulses or, in some applications as an integrated stream.
  • Proportional counter
  • Geiger- Müller counter: Counts individual ionizing particles regardless of their type and energy. Suitable Depending on the structure ( entrance window ) and fill gas for different particles
  • Spark counter ( streamer chamber )
  • Straw - detector
  • Multi-wire proportional chamber ( short wire chamber, English multi -wire proportional chamber, MWPC. )
  • Track drift chamber (german time projection chamber, TPC)
  • Resistive plate chamber ( engl. resistive plate chamber, RPC)
  • Microstructured gas detectors (English micro -pattern gas detector, MPGD ) achieve by reducing the read-out structures better spatial resolution than 'conventional' gas detectors and therefore represent an active research area dar. These include: Gas Electron Multiplier (abbreviated GEM)
  • Micromegas (English for Gaseous micromesh structure )

Semiconductor detectors

In semiconductor detectors of ionizing radiation produced similar ionization chambers (see above) free electric charges. These pulses are ( eg, transistors ) reinforced by appropriate circuits that can be assembled directly to the detector.

So can be used silicon pin photodiode in reverse direction at low operating voltage in a shielded light-tight and sensitive, high-impedance amplifier and subsequent noise-canceling discriminator or comparator.

Scintillation detectors

The scintillation detector is a detector that exploits the property of different materials to convert the excitation generated on passage of ionizing particles into light. The generated light is a function of the energy emitted by the particles. The resulting flash of light is detected, for example with a photocell with a downstream secondary electron multiplier.

Track detectors

  • Bubble chamber
  • Diffusion chamber
  • Wire chamber
  • Hodoscope
  • Spark chamber
  • Cloud chamber

Cherenkov detectors

A Cherenkov detector is a detector that uses the Cherenkov effect for the detection of particles. There are various designs, ranging from measuring whether light is emitted ( threshold detector ), up to the determination of the direction and angle of the light cone (for example RICH and DIRC ).

Cherenkov detectors can be very large and therefore suitable as neutrino detectors.

Other methods

  • Transition Radiation Detector (English Transition Radiation Detector TRD short ): These detectors usually consist of a stack of sheets perpendicular to the direction of the Teilchendurchgangs. By detection of the transition radiation, it is possible to identify the passing particles.
  • Particle detectors, which detect slow electrons or ions: the particles solve one or more electrons from a suitable surface, they are in a secondary electron multiplier ( channeltron for example ) multiplied and detected
  • Electromagnetic calorimeter

Evidence of uncharged particles

  • Neutron detectors: Fast neutrons (mostly protons) detected via elastic initiated charged particles.
  • Slow and thermal neutrons can be detected by appropriate nuclear reactions (for example with 10Bor ) and detection of the resulting charged particles.
ALICE: A Large Ion Collider Experiment Gaseous ionization detectors Calorimeter (particle physics)
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