ALEPH | Apparatus for LEPPHysics |
---|---|
DELPHI | DEtector with Lepton, Photon and Hadron Identification |
OPAL | Omni-Purpose Apparatus for LEP |
L3 | Third LEP experiment |
ALEPH was a particle detector at the Large Electron-Positron collider (LEP) at CERN. It was designed to explore the physics predicted by the Standard Model and to search for physics beyond it. [1] [2] [3]
The ALEPH detector was built to measure events created by electron positron collisions in LEP. It operated from 1989 to 1995 in the energy range of the Z particle (around 91 GeV) and later (1995 to 2000) above the threshold of W pair production (up to 200 GeV)[ citation needed ]. Typical events have many particles distributed in jets over the entire detector volume. The event rate ranged from around 1 Hz at the peak of the Z to at least a factor hundred smaller at the highest energies. The ALEPH detector was therefore designed to accumulate, for each event, as much information over as much solid angle as was practical.
This was achieved by a cylindrical arrangement around the beam pipe with the electron-positron interaction point in the middle. A magnetic field of 1.5 Tesla was created by a superconducting coil 6.4 m long and 5.3 m in diameter. The iron return yoke was a dodecagonal cylinder with two end-plates that left holes for a focusing magnet (quadrupole) of the LEP machine. The iron was 1.2 m thick and was subdivided into layers that left space for the insertion of layers of streamer tubes. In this way the iron yoke was a fully instrumented hadron calorimeter (HCAL), which was read out in 4608 projective towers. Outside the iron, there were two double layers of streamer tube chambers to record the position and angle of muons that had penetrated the iron. [4]
Inside the coil was the electron-photon calorimeter (ECAL), designed for the highest possible angular resolution and electron identification. It consisted of alternating layers of lead and proportional tubes read out in 73,728 projective towers, each subdivided into three depth zones. The central detector for charged particles was the time projection chamber (TPC), 4.4 m long and 3.6 m in diameter. It provided a three dimensional measurement of each track segment. In addition, it provided up to 330 ionisation measurements for a track; this was useful for particle identification. The TPC surrounded the inner track chamber (ITC); an axial-wire drift chamber with inner and outer diameters of 13 cm and 29 cm and a length of 2 m. It provided 8 track coordinates and a trigger signal for charged particles that came from the interaction point. Closest to the beam pipe, was a silicon strip vertex detector. For each track, this measured two pairs of coordinates, 6.3 cm and 11 cm away from the beam axis over a length of 40 cm along the beam line. The beam pipe, made out of beryllium, had a diameter of 16 cm. The vacuum inside was about 10−15 atm. [5] [6]
The Compact Muon Solenoid (CMS) experiment is one of two large general-purpose particle physics detectors built on the Large Hadron Collider (LHC) at CERN in Switzerland and France. The goal of the CMS experiment is to investigate a wide range of physics, including the search for the Higgs boson, extra dimensions, and particles that could make up dark matter.
The Large Electron–Positron Collider (LEP) was one of the largest particle accelerators ever constructed. It was built at CERN, a multi-national centre for research in nuclear and particle physics near Geneva, Switzerland.
A wire chamber or multi-wire proportional chamber is a type of proportional counter that detects charged particles and photons and can give positional information on their trajectory, by tracking the trails of gaseous ionization. The technique was an improvement over the bubble chamber particle detection method, which used photographic techniques, as it allowed high speed electronics to track the particle path.
The Compact Linear Collider (CLIC) is a concept for a future linear particle accelerator that aims to explore the next energy frontier. CLIC would collide electrons with positrons and is currently the only mature option for a multi-TeV linear collider. The accelerator would be between 11 and 50 km long, more than ten times longer than the existing Stanford Linear Accelerator (SLAC) in California, US. CLIC is proposed to be built at CERN, across the border between France and Switzerland near Geneva, with first beams starting by the time the Large Hadron Collider (LHC) has finished operations around 2035.
The Underground Area 2 (UA2) experiment was a high-energy physics experiment at the Proton-Antiproton Collider — a modification of the Super Proton Synchrotron (SPS) — at CERN. The experiment ran from 1981 until 1990, and its main objective was to discover the W and Z bosons. UA2, together with the UA1 experiment, succeeded in discovering these particles in 1983, leading to the 1984 Nobel Prize in Physics being awarded to Carlo Rubbia and Simon van der Meer. The UA2 experiment also observed the first evidence for jet production in hadron collisions in 1981, and was involved in the searches of the top quark and of supersymmetric particles. Pierre Darriulat was the spokesperson of UA2 from 1981 to 1986, followed by Luigi Di Lella from 1986 to 1990.
In physics, a time projection chamber (TPC) is a type of particle detector that uses a combination of electric fields and magnetic fields together with a sensitive volume of gas or liquid to perform a three-dimensional reconstruction of a particle trajectory or interaction.
DELPHI was one of the four main detectors of the Large Electron–Positron Collider (LEP) at CERN, one of the largest particle accelerators ever made. Like the other three detectors, it recorded and analyzed the result of the collision between LEP's colliding particle beams. The specific focus of DELPHI was on particle identification, three-dimensional information, high granularity (detail), and precise vertex determination.
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ALICE is one of nine detector experiments at the Large Hadron Collider at CERN. The experiment is designed to study the conditions that are thought to have existed immediately after the Big Bang by measuring properties of quark-gluon plasma.
The DØ experiment was a worldwide collaboration of scientists conducting research on the fundamental nature of matter. DØ was one of two major experiments located at the Tevatron Collider at Fermilab in Batavia, Illinois. The Tevatron was the world's highest-energy accelerator from 1983 until 2009, when its energy was surpassed by the Large Hadron Collider. The DØ experiment stopped taking data in 2011, when the Tevatron shut down, but data analysis is still ongoing. The DØ detector is preserved in Fermilab's DØ Assembly Building as part of a historical exhibit for public tours.
The Mark I, also known as the SLAC-LBL Magnetic Detector, was a particle detector that operated at the interaction point of the SPEAR collider from 1973 to 1977. It was the first 4π detector, i.e. the first detector to uniformly cover as much of the 4π steradians around the interaction point as possible with different types of component particle detectors arranged in layers. This design proved quite successful, and the detector was used in discoveries of the
J/ψ
particle and tau lepton, which both resulted in Nobel prizes. This basic design philosophy continues to be used in all modern collider detectors.
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The Underground Area 7 (UA7) experiment was a high-energy physics experiment at the Proton-Antiproton Collider, a modification of the Super Proton Synchrotron (SPS), at CERN. The purpose of the experiment was to measure the invariant cross section of photons and neutral pions (π0) emitted close to zero degrees, by using silicon shower detectors. The experiment data taking ran from 1985 to 1986, and the final analysis was completed in 1996.
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