The Liquid Scintillator Neutrino Detector (LSND) was a
scintillation counter
A scintillation counter is an instrument for detecting and measuring ionizing radiation by using the excitation effect of incident radiation on a scintillating material, and detecting the resultant light pulses.
It consists of a scintillator w ...
at
Los Alamos National Laboratory
Los Alamos National Laboratory (often shortened as Los Alamos and LANL) is one of the sixteen research and development laboratories of the United States Department of Energy (DOE), located a short distance northwest of Santa Fe, New Mexico, ...
that measured the number of
neutrino
A neutrino ( ; denoted by the Greek letter ) is a fermion (an elementary particle with spin of ) that interacts only via the weak interaction and gravity. The neutrino is so named because it is electrically neutral and because its rest mass ...
s being produced by an accelerator neutrino source. The LSND project was created to look for evidence of
neutrino oscillation, and its results conflict with the standard model expectation of only three neutrino
flavors
Flavor or flavour is either the sensory perception of taste or smell, or a flavoring in food that produces such perception.
Flavor or flavour may also refer to:
Science
*Flavors (programming language), an early object-oriented extension to Lis ...
, when considered in the context of other solar and atmospheric neutrino oscillation experiments. Cosmological data bound the mass of the
sterile neutrino
Sterile neutrinos (or inert neutrinos) are hypothetical particles (neutral leptons – neutrinos) that are believed to interact only via gravity and not via any of the other fundamental interactions of the Standard Model. The term ''sterile neutrin ...
to m
s < 0.26eV (0.44eV) at 95% (99.9%) confidence limit, excluding at high significance the
sterile neutrino hypothesis as an explanation of the LSND anomaly.
[
] The controversial LSND result was tested by the
MiniBooNE
MiniBooNE is a Cherenkov detector experiment at Fermilab designed to observe neutrino oscillations (BooNE is an acronym for the Booster Neutrino Experiment). A neutrino beam consisting primarily of muon neutrinos is directed at a detector fill ...
experiment at
Fermilab
Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a United States Department of Energy national laboratory specializing in high-energy particle physics. Since 2007, Fermilab has been operat ...
which has found similar evidence for oscillations.
The hint is currently undergoing further tests at
MicroBooNE
MicroBooNE is a liquid argon time projection chamber (LArTPC) at Fermilab in Batavia, Illinois. It is located in the Booster Neutrino Beam (BNB) beamline where neutrinos are produced by colliding protons from Fermilab's booster-accelerator on a be ...
at
Fermilab
Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a United States Department of Energy national laboratory specializing in high-energy particle physics. Since 2007, Fermilab has been operat ...
.
The detector consisted of a tank filled with 167 tons (50,000 gallons) of
mineral oil
Mineral oil is any of various colorless, odorless, light mixtures of higher alkanes from a mineral source, particularly a distillate of petroleum, as distinct from usually edible vegetable oils.
The name 'mineral oil' by itself is imprecise, ...
and of
b-PDB
Butyl PBD or b-PBD (short for butyl-phenyl-bipheny-oxydiazole) is a fluorescent organic compound used in the Liquid Scintillator Neutrino Detector (LSND) at Los Alamos National Laboratory, USA..
The fluorescent emission of b-PBD is at ''λ''em&n ...
(
2-(4-tert-butylphenyl)-5-(4-biphenyl)-1,3,4-oxadiazole
Butyl PBD or b-PBD (short for butyl-phenyl-bipheny-oxydiazole) is a fluorescent
Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It is a form of luminescence. In most cases, t ...
) organic scintillator material.
Cherenkov light emitted by particle interactions was detected by an array of 1220
photomultiplier A photomultiplier is a device that converts incident photons into an electrical signal.
Kinds of photomultiplier include:
* Photomultiplier tube, a vacuum tube converting incident photons into an electric signal. Photomultiplier tubes (PMTs for sho ...
tubes. The experiment collected data from 1993 to 1998.
References
Further reading
*
External links
LSND strengthens evidence for neutrino oscillationsLSND scientific publicationsLSND scientific publications, SPIRES databaseThe Neutrino Oscillations Industry
Accelerator neutrino experiments
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