Neutrino detectorIs observationneutrinoExperimental equipment.Because neutrinos only participateWeak interactionGenerally, detectors need to be built large enough to receive enough neutrino signals.Neutrino detectors are usually built deep underground to shieldcosmic raysAnd othersBackground radiation。Neutrino astronomyIt is not yet mature, and the only confirmed signal sources from outside the earth aresunlightAnd supernovaeSN 1987A。However, in the future, the neutrino observatory will "provide astronomers with a new perspective to analyze the universe".
Neutrino detectorIs observationneutrinoExperimental equipment.Because neutrinos only participateWeak interactionGenerally, detectors need to be built large enough to receive enough neutrino signals.Neutrino detectors are usually built deep underground to shieldcosmic raysAnd other background radiation.Neutrino astronomyIt is not yet mature, and the only confirmed signal sources from outside the earth aresunlightAnd supernovaeSN 1987A。However, in the future, the neutrino observatory will "provide astronomers with a new perspective to analyze the universe".
Barker Third Neutrino Observatory(former Soviet Union), opened in 1977.[1]
neutrino
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neutrino(Italian:Neutrino, which literally means "tiny electrically neutral particles"Neutrino）It is electrically neutralElementary particle，Spin quantum numberIs ½, marked by the Greek letter ν.Now there is evidence that it has quality.But its mass is very small even compared with other subatomic particles.It may be the only one that has been detecteddark substance, is a kind ofHot dark matter。
Since neutrinos are electrically neutral and also a kind of lepton, they do not participateElectromagnetic interactionas well asStrong interaction。It only participatesWeak interactionas well asGravitational interaction。Because the interaction distance of weak interaction is very short, and the gravitational interaction is very weak at the subatomic scale, neutrinos will not be blocked too much when passing through ordinary substances, and it is difficult to detect.
Neutrinos can pass throughRadioactive decayas well asnuclear reactionAnd so on.Because nuclear reactions are taking place in the sun all the timeSupernovaProduction and other processes will also be accompanied by intense nuclear reactions, socosmic raysNeutrinos can be detected in.Most of the neutrinos detected near the Earth originate from the sun.In fact, the area of the Earth facing the sun will pass through about 65 billion neutrinos from the sun every second in every square centimeter.
It is now recognized that neutrinos will be in different flavors during flightoscillation, such asBeta decayThe electric neutrinos generated in may become μ neutrinos or τ neutrinos during detection.This phenomenon indicates that neutrinos have mass, and the quality of neutrinos with different flavors is also different.According to the presentcosmologyThe sum of the neutrino masses of the three flavors is less than one millionth of the electron mass in the detected data.[1]
stayParticle physicsOfStandard modelThe theory of weak interaction points out thatW and Z bosonsThe weak force is caused by the emission (or absorption) of bosons, so it is aNon-contact force。The most famous of these launches isBeta decay, it isradioactivityA performance of.Heavy particles are unstable in nature. Since Z and W bosons are much heavier than protons or neutrons, the interaction distance of weak interaction is very short.This interaction is called "weak" because the probability of beta decay is much lower than that of strong interaction, which means that its general intensity ratioelectromagnetismandStrong nuclear forceSeveral weakOrder of magnitude。Most particles will decay through weak interaction after a period of time.The weak interaction has a unique characteristic that isquarkTaste changes - other interactions cannot do this.In addition, it will destroyParity symmetryandCP symmetry。The flavor change of quarks enables quarks to“taste”Interchangeable.
The earliest description of weak force is in the 1930s, which is fourFermionContact interactingFermi theory: Contact refers to no operating distance (i.e. completely physical contact).But now it is better to describe it in terms of a field with an effective distance, although that distance is very short.In 1968, electromagnetic and weak interaction were unified. They are two aspects of the same force, now calledWeak current interaction。
Weak interaction in theBeta decayIs the most obvious in hydrogen productionDeuteriumandheliumThe process (energy source of star thermonuclear reaction) is also very obvious.Radiocarbon datingThis is the decayCarbon-14Decay through weak interactionNitrogen - 14。It can also createRadiant cold light, common inSuperheavy hydrogenLighting;Has also createdBeta voltThis application field (Beta rayThe electrons of are used as current).[1]
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In May 2022, it was learned from the Institute of High Energy Physics of the Chinese Academy of Sciences that the second large-scale neutrino experiment project, Jiangmen Neutrino Experiment, hosted by China, is under construction 700 meters underground in Dashi Mountain, Jiangmen City, Guangdong Province.In the 700m underground experimental hall, the lifting platform installed from top to bottom to achieve the perspex ball layer by layer has been installed and jacked up to 38m, like a giant "Transformers Tower", preparing for the next installation of the perspex ball.[2]
