- H1 (particle detector)
H1 is a
particle detectorin operation at HERA (" Hadron Elektron Ring Anlage") in DESY, Hamburg. It began operating together with HERA in 1992. Leptons( electrons or positrons) are collided with protons by HERA in the interaction pointof H1. H1 is operated by an internationalcollaboration of about 400 physicists from 42 institutes in 15 countries. The detectoris about 12 x 15 x 10 meters big and weighs 2800 tons. It is accompanied by an electronics trailer 3 stories high.
While H1 is a general purpose detector its main design feature is an asymmetric constructionto cope with the
boosted center of massin the laboratory frame due to the large energy imbalance of the colliding beams.In the forward (incident proton) direction the instrumentation has higher granularity to give a betterresolution for refined measurement of the proton remnant left after the collision with the incident lepton.The reaction products, often including the proton remnant and the scattered lepton, are detected by several subdetectors. Combination of their information allows the identification of particles from the reaction,or a least the reconstruction of the overall reaction kinematics. This in turn allows the classification ofthe reaction. From the center outwards, H1's most important systems are:
* Silicon trackers for the determination of primary and secondary vertices.
Jet chambers for the measurement of charged particle tracks.
Argon(LAr) calorimeter for the measurement of electromagneticand hadronicshowers.
* Lead/scintillating fibre calorimeter (SpaCal) in the backward direction for the measurement of the scattered lepton.
* Muon detectors in the iron magnet yoke surrounding H1 and in the forward direction.In addition to these systems, H1 has several helper systems, such as a
luminositysystem, ToF (time of flight) detectors and radiationmonitors. Also in the course of time additional detector systems have been added as the focus on special physics processes has become bigger. For example, forward instrumentation for diffractive physics has been added far down the HERA tunnel.
The most interesting physics topics treated at H1 include
* Cross section measurements of reactions with charged and neutral
* Studies of proton structure and determination of
quarkand gluonparton distribution functions
* Tests of QCD in jet and particle production
* Production of heavy
quarks ( charmand bottom)
* Diffraction (physics with the exchange of a
* Search for physics beyond the
Standard Model(For example the substructure of quarks / contact interactions, Leptoquarks, magnetic monopole)
The H1 detector took data until the shutdown of HERA in June
* [http://www-h1.desy.de/general/home/home.html H1 Homepage]
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