Magnetic horn

Last updated

A magnetic horn or neutrino horn (also known as the Van der Meer horn) is a high-current, pulsed focusing device, invented by the Dutch physicist Simon van der Meer in CERN, that selects pions and focuses them into a sharp beam. The original application of the magnetic horn was in the context of neutrino physics, where beams of pions have to be tightly focused. When the pions then decay into muons and neutrinos or antineutrinos, a focused neutrino beam is obtained.

Contents

Description

Production of a neutrino beam generally involves directing protons onto a fixed target of solid material. The protons interact strongly with the nuclei in the target, producing a variety of secondary hadrons. The proton beam energy and target material are chosen so that these hadrons are mostly pions and kaons. Both of these particles' decays produce neutrinos. However, without a neutrino horn, the resulting neutrino beam is very wide, both geometrically and in energy spread. This is because the secondary particles are produced at a variety of angles and energies and then when they decay, the neutrinos are again produced at a variety of angles and energies.

The neutrinos themselves cannot be focused with electric or magnetic fields because they are electrically neutral. Instead, one or more magnetic horns can be used to focus the secondary particles. The shape of the horn and strength of the magnetic field can be tuned to select a range of particle energies that are to be best focused. In this way, the resulting neutrino beam is both geometrically focused and given a chosen range of energies. Note however that the decays of the secondary hadrons still impart some random direction to the neutrinos, so the beam will always spread to some degree no matter how well the horn works.

Notable uses

Related Research Articles

<span class="mw-page-title-main">Compact Muon Solenoid</span> General-purposes experiment at the Large Hadron Collider

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.

<span class="mw-page-title-main">ATLAS experiment</span> CERN LHC experiment

ATLAS is the largest general-purpose particle detector experiment at the Large Hadron Collider (LHC), a particle accelerator at CERN in Switzerland. The experiment is designed to take advantage of the unprecedented energy available at the LHC and observe phenomena that involve highly massive particles which were not observable using earlier lower-energy accelerators. ATLAS was one of the two LHC experiments involved in the discovery of the Higgs boson in July 2012. It was also designed to search for evidence of theories of particle physics beyond the Standard Model.

The International Muon Ionization Cooling Experiment is a high energy physics experiment at the Rutherford Appleton Laboratory. The experiment is a recognized CERN experiment (RE11). MICE is designed to demonstrate ionization cooling of muons. This is a process whereby the emittance of a beam is reduced in order to reduce the beam size, so that more muons can be accelerated in smaller aperture accelerators and with fewer focussing magnets. This might enable the construction of high intensity muon accelerators, for example for use as a Neutrino Factory or Muon Collider.

<span class="mw-page-title-main">Gargamelle</span> CERN Bubble chamber particle detector

Gargamelle was a heavy liquid bubble chamber detector in operation at CERN between 1970 and 1979. It was designed to detect neutrinos and antineutrinos, which were produced with a beam from the Proton Synchrotron (PS) between 1970 and 1976, before the detector was moved to the Super Proton Synchrotron (SPS). In 1979 an irreparable crack was discovered in the bubble chamber, and the detector was decommissioned. It is currently part of the "Microcosm" exhibition at CERN, open to the public.

<span class="mw-page-title-main">Jack Steinberger</span> German-American physicist, Nobel laureate (1921–2020)

Jack Steinberger was a German-born American physicist noted for his work with neutrinos, the subatomic particles considered to be elementary constituents of matter. He was a recipient of the 1988 Nobel Prize in Physics, along with Leon M. Lederman and Melvin Schwartz, for the discovery of the muon neutrino. Through his career as an experimental particle physicist, he held positions at the University of California, Berkeley, Columbia University (1950–68), and the CERN (1968–86). He was also a recipient of the United States National Medal of Science in 1988, and the Matteucci Medal from the Italian Academy of Sciences in 1990.

The Neutrino Factory is a proposed particle accelerator complex intended to measure in detail the properties of neutrinos, which are extremely weakly interacting fundamental particles that can travel in straight lines through normal matter for thousands of kilometres. Up until the 1990s, neutrinos were assumed to be massless, but experimental results from searches for solar neutrinos and others are inconsistent with this assumption, and thus indicate that the neutrino does have a very small mass.

T2K is a particle physics experiment studying the oscillations of the accelerator neutrinos. The experiment is conducted in Japan by the international cooperation of about 500 physicists and engineers with over 60 research institutions from several countries from Europe, Asia and North America and it is a recognized CERN experiment (RE13). T2K collected data within its first phase of operation from 2010 till 2021. The second phase of data taking is expected to start in 2023 and last until commencement of the successor of T2K – the Hyper-Kamiokande experiment in 2027.

<span class="mw-page-title-main">COMPASS experiment</span>

The NA58 experiment, or COMPASS is a 60-metre-long fixed-target experiment at the M2 beam line of the SPS at CERN. The experimental hall is located at the CERN North Area, close to the French village of Prévessin-Moëns. The experiment is a two-staged spectrometer with numerous tracking detectors, particle identification and calorimetry. The physics results are extracted by recording and analysing the final states of the scattering processes.

Neutrinos at the Main Injector, or NuMI, is a project at Fermilab which creates an intense beam of neutrinos aimed towards the Far Detector facility near Ash River, Minnesota for use by several particle detectors. As of June 2010, the MINOS, MINERνA and NOνA experiments use the NuMI beam.

The Oscillation Project with Emulsion-tRacking Apparatus (OPERA) was an instrument used in a scientific experiment for detecting tau neutrinos from muon neutrino oscillations. The experiment is a collaboration between CERN in Geneva, Switzerland, and the Laboratori Nazionali del Gran Sasso (LNGS) in Gran Sasso, Italy and uses the CERN Neutrinos to Gran Sasso (CNGS) neutrino beam.

<span class="mw-page-title-main">NA62 experiment</span>

The NA62 experiment is a fixed-target particle physics experiment in the North Area of the SPS accelerator at CERN. The experiment was approved in February 2007. Data taking began in 2015, and the experiment is expected to become the first in the world to probe the decays of the charged kaon with probabilities down to 10−12. The experiment's spokesperson is Cristina Lazzeroni. The collaboration involves 333 individuals from 30 institutions and 13 countries around the world.

<span class="mw-page-title-main">CERN Neutrinos to Gran Sasso</span>

The CERN Neutrinos to Gran Sasso (CNGS) project was a physics project of the European Organization for Nuclear Research (CERN). The aim of the project was to analyse the hypothesis of neutrino oscillation by directing a beam of neutrinos from CERN's facilities to the detector of the OPERA experiment at the Gran Sasso National Laboratory (LNGS), located in the Gran Sasso mountain in Italy. The CNGS facility was housed in a tunnel which diverged from one of the SPS–LHC transfer tunnels, at the Franco–Swiss border near Geneva. It used the Super Proton Synchrotron (SPS) accelerator as a source of high-energy protons.

MINOS+ was a continuation of the MINOS experiment to measure neutrino oscillation with improved electronics. It started taking data in 2013 and ran for 3 years. The experiment has ended and a 6-month dismantling project began in early October 2016.

<span class="mw-page-title-main">Accelerator Neutrino Neutron Interaction Experiment</span> Water Cherenkov detector experiment

The Accelerator Neutrino Neutron Interaction Experiment (ANNIE) is a proposed water Cherenkov detector experiment designed to examine the nature of neutrino interactions. This experiment will study phenomena like proton decay, and neutrino oscillations, by analyzing neutrino interactions in gadolinium-loaded water and measuring their neutron yield. Neutron Tagging plays an important role in background rejection from atmospheric neutrinos. By implementing early prototypes of LAPPDs, high precision timing is possible. The suggested location for ANNIE is the SciBooNE hall on the Booster Neutrino Beam associated with the MiniBooNE experiment. The neutrino beam originates in Fermilab where The Booster delivers 8 GeV protons to a beryllium target producing secondary pions and kaons. These secondary mesons decay to produce a neutrino beam with an average energy of around 800 MeV. ANNIE will begin installation in the summer of 2015. Phase I of ANNIE, mapping the neutron background, completed in 2017. The detector is being upgraded for full science operation which is expected to begin late 2018.

<span class="mw-page-title-main">Luigi Di Lella</span> Italian experimental particle physicist

Luigi Di Lella is an Italian experimental particle physicist. He has been a staff member at CERN for over 40 years, and has played an important role in major experiments at CERN such as CAST and UA2. From 1986 to 1990 he acted as spokesperson for the UA2 Collaboration, which, together with the UA1 Collaboration, discovered the W and Z bosons in 1983.

<span class="mw-page-title-main">David B. Cline</span> American particle physicist

]

The Enhanced NeUtrino BEams from kaon Tagging or ENUBET is an ERC funded project that aims at producing an artificial neutrino beam in which the flavor, flux and energy of the produced neutrinos are known with unprecedented precision.

<span class="mw-page-title-main">FASER experiment</span> 2022 particle physics experiment at the Large Hadron Collider at CERN

FASER is one of the nine particle physics experiments in 2022 at the Large Hadron Collider at CERN. It is designed to both search for new light and weakly coupled elementary particles, and to detect and study the interactions of high-energy collider neutrinos. In 2023, FASER and SND@LHC reported the first observation of collider neutrinos.

An accelerator neutrino is a human-generated neutrino or antineutrino obtained using particle accelerators, in which beam of protons is accelerated and collided with a fixed target, producing mesons which then decay into neutrinos. Depending on the energy of the accelerated protons and whether mesons decay in flight or at rest it is possible to generate neutrinos of a different flavour, energy and angular distribution. Accelerator neutrinos are used to study neutrino interactions and neutrino oscillations taking advantage of high intensity of neutrino beams, as well as a possibility to control and understand their type and kinematic properties to a much greater extent than for neutrinos from other sources.

Monitored neutrino beams are facilities for the production of neutrinos with unprecedented control of the flux of particles created inside and outside the facility.

References

  1. Cheryl Patrick. "Recent results from MINERvA" (PDF). Indico.in2p3.fr. Retrieved 2022-03-12.