365:. The characteristic build-up time expected for the HERA accelerator was approximately 40 minutes. Spin rotators on either side of the experiments changed the transverse polarisation of the beam into longitudinal polarisation. The positron beam polarisation was measured using two independent polarimeters, the transverse polarimeter (TPOL) and the longitudinal polarimeter (LPOL). Both devices exploit the spin-dependent cross section for
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of circularly polarised photons off positrons to measure the beam polarisation. The transverse polarimeter was upgraded in 2001 to provide a fast measurement for every positron bunch, and position-sensitive silicon strip and scintillating-fibre detectors were added to investigate systematic effects.
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and pre-accelerated to 50 MeV in a linear accelerator. They were then injected into the proton synchrotron DESY III and accelerated further to 7 GeV. Then they were transferred to PETRA, where they were accelerated to 40 GeV. Finally, they were injected into their storage ring in
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H1 was a universal detector for the collision of electrons and protons, located in the HERA Hall North. It measured 12 m Ă— 10 m Ă— 15 m, weighed 2800 tons and was operated from 1992 to 2007. It was designed for probing the inner structure of the proton, the exploration of the strong
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The construction of HERA was one of the first truly internationally financed projects of this magnitude. Previously, the construction of scientific facilities was always financed by the country in which they were located. Only the costs for the experiments were borne by the conducting national or
261:) the magnitude of their differential cross sections become comparable so the charged and neutral currents (CC (red) & NC (blue)) appear indistinguishable but it also becomes lower so they look hard to distinguish from the massless photon too, that is EW unification starts to set in.
269:, which was also a world first. At HERA, it was possible to study the structure of protons up to 30 times more accurately than before. The resolution covered structures 1/1000 of the proton in size, facilitating many discoveries concerning the composition of protons from quarks and
469:. For this purpose, the electrons were scattered at energies of 27.5 GeV at an internal gas target. This target and the detector itself were designed especially with a view to spin-polarised physics. The detector measured 3.5 m Ă— 8 m Ă— 5 m and weighed 400 tons.
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were located on top of each other inside the tube. One accelerated electrons to energies of 27.5 GeV, the other one protons to energies of 920 GeV in the opposite direction. Both beams completed their circle nearly at the speed of light, making approximately
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HERA-B was an experiment in the HERA Hall West, which collected data from 1999 to
February 2003. By using HERA's proton beam, researchers at HERA-B conducted experiments on heavy quarks. The detector measured 8 m Ă— 20 m Ă— 9 m and weighed 1000 tons.
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Following the example of HERA, many large-scale scientific projects have since then been financed jointly by several countries. This model has become established and international cooperation is moderately common in the construction of those facilities.
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Like H1, ZEUS was a detector for electron–proton collisions, located in the HERA Hall South. It measured 12 m × 11 m × 20 m, weighed 3600 tons and was operated from 1992 to 2007. Its tasks were similar to those of H1.
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run by international groups of researchers. These groups developed, constructed and ran the multi-storey, complex measurement devices in many years of cooperative work and evaluated enormous amounts of data.
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More than 45 institutes and 320 corporations participated in the construction of the facility with donations of money or materials, and more than 20% of the costs were borne by foreign institutions.
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Abramowicz, H.; Abt, I.; Adamczyk, L.; Adamus, M.; Andreev, V.; Antonelli, S.; Antunović, B.; Aushev, V.; Aushev, Y.; Baghdasaryan, A.; Begzsuren, K. (8 December 2015).
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On 30 June 2007 at 11:23 pm, HERA was shut down, and dismantling of the four experiments started. HERA's main pre-accelerator PETRA was converted into a
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A small segment of the HERA tunnel. The proton beam is travelling in the large vacuum tube in the middle to the right, the electron beam tube is below that.
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is mediated to first order therefore when the momentum transfer-squared becomes bigger than the mass of the charged W and the neutral Z boson squared (<
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since 2009. Today, a section of the HERA tunnel and 24 former superconducting dipole magnets are being used for the new ALPS experiment, which looks for
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foreign institutes. Due to the enormous scope of the HERA project, many international institutions agreed to participate already in the construction.
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of 6.3 km and an inner diameter of 5.2 m. For the construction, the same technology was used as for the construction of subway tunnels. Two
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the HERA tunnel and reached their final energy of 920 GeV. The proton storage ring used superconducting magnets to keep the protons on track.
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The HERMES experiment in the HERA Hall East was operated from 1995 to 2007. HERA's longitudinally polarised electron beam was used to explore the
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in the linear accelerator LINAC II. From there, they were injected into the storage ring DESY II and accelerated further to 7.5
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interaction as well as the search for new kinds of matter and unexpected phenomena in particle physics.
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around the ring, which were used by the experiments
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particle physics laboratory today. HERA is the only
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842:Buildings and structures in Altona, Hamburg
564:Heuer, R.-D.; Wagner, A. (21 August 2007).
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124:Learn how and when to remove this message
566:"HERA leaves a rich legacy of knowledge"
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687:"Any Light Particle Search (ALPS) II"
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537:Warmbein, Barbara (21 August 2007).
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539:"End of an era: HERA Switches off"
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709:"Last run of HERA (30 June 2007)"
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389:International project HERA
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29:Hera (disambiguation)
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367:Compton scattering
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461:HERMES experiment
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836:Categories
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181:ccelerator
114:March 2022
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809:9°53′13″E
719:6 October
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201:positrons
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