The H1-Experiment at HERA

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The H1 Detector

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Detector Graphic

  1. Beam pipe and beam magnets
  2. Central tracking chambers
  3. Forward tracking and Transition radiators
  4. Electromagnetic Calorimeter (lead, liquidargon)
  5. Hadronic Calorimeter (stainess steel)
  6. Superconducting coil (1,2T)
  7. Compensating magnet
  8. Helium cryogenics
  9. Muon cambers
  10. Return yoke (instrumented iron with streamer tubes
  11. Myon-Toroid-Magnet
  12. Warm calorimeter (Spacal)
  13. Plug calorimeter
  14. Concrete screen
  15. Liquid Argon cryostat.

HERA

Hera is a unique facility in the world where electrons and protons are accelerated to the highest collision energies ever attained. HERA consists of two storage rings, one for protons of 820 GeV and one for electrons (or positrons) of 30 GeV. The two beams circulate in opposite directions in an underground tunnel, 6.3km in length. At two interaction points the particle beams are directed against each other and collisions between protons end electrons take place. The reaction products are measured by large detectors like H1.

H1

H1 is a collaboration of about 400 scientists of 39 institues from 12 countries throughout the world. A large particle detector has been constructed by H1 in the Hall North of the HERA accelerator, for studying collisions between electrons and protons . The internal structure of the proton is being investigated with unprecedent accuracy by this detector, which is also suitable for searching for hitherto unobserved particles. The unique experiment will lead to a better understanding of the various particles that make up our world and the interactive forces between them. The picture shows the H1-detector being moved into its final position at HERA in February 1992.

Detector.gif (97K)

H1 was designed to detect and measure the energetic particles and jets emitted in the reactions taking place in collisions between electrons and protons at HERA. Special emphasis was placed on the identification of these particles, especially electrons and muons. The fact that the protons enter the interaction zone with much higher energy than the electrons was also taken into account.

The design and construction of the calorimeter was one of the most challenging tasks for the scientists and engineers in H1. The determination of the jet energy is performed by reliable and stable techniques using liquid argon ionisation chambers. The interaction zone is surrounded by the calorimeter so that practically no particles can escape undetected. In addition it is divided into very small cells so that the jets can be very well localised in space.

The tracks of charged particles are measured in various kinds of wire chambers. Points along the the track can be measured with an accuracy of about a thenth of a millimeter and in this way the curvature of the tracks in the magnetic field can be determined, thus allowing the momentum of the particles to be calculated.

The data flow resulting from the interactions is prodigious and after careful filtering and sorting using the most up-to-date technique available at the present time, the resulting information is stored on magnetic tape cartridges at the DESY central main frame computer, for subsequent analysis.

The structure of the proton

This is the web version of an H1 leaflet (Status 3.96)

Translated to html by C.Preine (3.96)

Last updated 27.3.96 by JB