[HN Gopher] DUNE scientists observe first neutrinos with prototy...
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DUNE scientists observe first neutrinos with prototype detector at
Fermilab
Author : croes
Score : 147 points
Date : 2024-08-13 16:02 UTC (1 days ago)
(HTM) web link (newscenter.lbl.gov)
(TXT) w3m dump (newscenter.lbl.gov)
| bloopernova wrote:
| Non-physicist question:
|
| What purpose do neutrinos serve in the complex world of
| elementary particles?
|
| Are they "just" a side effect of radioactive decay, or do they
| facilitate some other reaction?
|
| (edited to change the original question from "what are neutrinos
| _for_? " to the current question which was suggested by a
| grandchild comment)
| pif wrote:
| > what are neutrinos for?
|
| I'm not sure I understand your question, sorry!
|
| > Are they "just" a side effect of radioactive decay
|
| They are (as fas as we know) elementary particles as several
| other elementary particles.
|
| > do they facilitate some other reaction?
|
| Again, I'm not sure I get the sense of your question, but I'd
| say no, as they are the most elusive particles we know.
| gus_massa wrote:
| Oversimplifiying, they are chargeless electrons.
|
| If you have an electron(negative) and a proton (positive), then
| the charge may jump and you get a neutrino(no charge) and a
| neutron(no charge).
|
| It's more common in the other direction. If ypu have a
| neutron(no charge) it splits into a proton(positive), an
| electron(negative) an an antineutrino(no charge).
| perihelions wrote:
| - _" do they facilitate some other reaction?"_
|
| They are not carriers of a fundamental force, if that's what
| you are thinking about.
|
| https://en.wikipedia.org/wiki/Force_carrier
| at_a_remove wrote:
| Neutrinos were originally a kind of mathematical placeholder to
| allow for conservation of lepton number (electrons, muons,
| etc). Turns out that they're real! More to the point, you have
| six basic leptons (and their antiparticles) if you count the
| _types_ of neutrinos and six basic quarks (and their
| antiparticles). It 's an _interesting_ parallel.
|
| They react with very little, as it turns out. Chargeless, and
| so they care not for electromagnetic forces. Strong nuclear
| force is also a miss. Originally, it was thought that only the
| weak nuclear force was the way they could interact with matter,
| but with confirmation that they have a non-zero mass, they can
| also interact with gravity. This makes them both hard to
| detect, but also an excellent way to peer through things like
| clouds of interstellar dust, or through the Earth.
| jfengel wrote:
| Even zero mass particles interact with gravity. Anything with
| energy does.
|
| Having non zero mass means that at least in theory we could
| slow them down to get a better look at them. But so far we
| have no idea how, which means that we don't even know what
| the mass actually is. We just know from the way from the
| types of neutrinos observed that they can change type, and
| they couldn't do that if their mass were zero.
| AnimalMuppet wrote:
| > Having non zero mass means that at least in theory we
| could slow them down to get a better look at them. But so
| far we have no idea how...
|
| How about cosmic expansion? Of the neutrinos emitted early
| in the universe, shouldn't most still be around, given how
| weakly neutrinos interact? And, given how much everything
| in the early universe is receding from us, shouldn't they
| be slowed down in our frame of reference? If they were
| emitted when the universe became transparent to neutrinos,
| what Z would that correspond to? What velocity would we
| observe in the local frame of reference? (Does it depend on
| _how close_ to c their velocity is? Do we know?)
|
| What would we expect the density of such neutrinos to be?
| Enough that we could observe it? (One "gotcha" is that
| slower-moving neutrinos might have a smaller interaction
| profile than fast-moving ones, and so be harder to detect.)
|
| Wikipedia says decoupling was at 1 second after the Big
| Bang, and that neutrinos from that era have energy of 1e-4
| to 1e-6 eV (compared to current neutrinos that may be as
| much as 0.8 eV).
| floxy wrote:
| I don't know any answers here, but this is an awesome
| question. I too am now super-curious about the Cosmic
| Neutrino Background.
|
| https://en.wikipedia.org/wiki/Cosmic_neutrino_background
|
| ...And I suppose there are probably good reasons for this
| to be impossible, but wouldn't it be wild if a
| "mechanism" for things like the "randomness" of beta
| decay were that a really slow/low energy neutrino from
| the big bang interacts with a neutron, causing it to
| decay into a proton, and an electron, and the neutrino
| gets a boost in energy as well.
| at_a_remove wrote:
| Sorry, I was being brief. I usually say "anything with a
| non-zero rest mass-energy" for anything for a photon,
| photons never being at rest. Briefly, some had thought that
| neutrinos might be little more than floating carriers of
| lepton number. Later that was amended to merely "massless"
| (in the sense that they would at least be like photons).
| I've never been in that crowd. My thoughts are that mass-
| energy is the coin of existence and gravitation the
| inevitable consequence, but I do not speak for everyone,
| just trying to give a kind of non-exhaustive overview of
| the history to respond to the _for_ part.
| Koshkin wrote:
| Neutrinos can interact with atoms, producing high-energy
| charged particles.
| nilkn wrote:
| Neutrinos must exist to satisfy conservation of lepton number.
| Specifically, the weak interaction can change flavor. In beta
| decay (for example), a down quark changes into an up quark,
| which converts a neutron into a proton and emits an electron.
| Conservation of lepton number implies that another particle
| must also be emitted with the properties of a neutrino.
| perihelions wrote:
| Fascinating that there's a neutrino beam cutting straight through
| the earth, in a chord hundreds of miles long, and they expect to
| be able to measure dozens of events per second (edit: at the
| closer of the two detectors--not the 800 mile one). If they were
| to modulate this beam, they could tweet-by-neutrino in near real-
| time.
|
| - _" DUNE is split between two locations hundreds of miles apart:
| A beam of neutrinos originating at Fermilab, close to Chicago,
| will pass through a particle detector located on the Fermilab
| site, then travel 800 miles through the ground to several huge
| detectors at the Sanford Underground Research Facility (SURF) in
| South Dakota."_
|
| - _" The DUNE detector at Fermilab will analyze the neutrino beam
| close to its origin, where the beam is extremely intense.
| Collaborators expect this near detector to record about 50
| interactions per pulse, which will come every second..."_
| pif wrote:
| > Fascinating that there's a neutrino beam cutting straight
| through the earth, in a chord hundreds of miles long
|
| This is not the first time! Search about neutrinos from CERN to
| Gran Sasso.
| perihelions wrote:
| OPERA collaboration!
|
| https://en.wikipedia.org/wiki/OPERA_experiment
| scheme271 wrote:
| The K2K experiment also sent a beam from KEK to SuperK in
| Japan. I think there might have been one or two other
| exeriments like this. If you spend the time and money to
| create a neutrino detector, doing an experiment like this is
| a reasonable add on.
| JumpCrisscross wrote:
| > _they could tweet-by-neutrino in near real-time_
|
| We demonstrated in 2012 a neutrino-based link which "achieved a
| decoded data rate of 0.1 bits/sec with a bit error rate of 1%
| over a distance of 1.035 km, including 240 m of earth" [1].
|
| To put that into perspective, a through-the-core beam would
| reach its antipode about 24 milliseconds before its
| circumnavigating partner [2].
|
| [1] https://arxiv.org/abs/1203.2847
|
| [2] _assuming a spherical earth with diameter 12 756 km [a] and
| circumference 40,075 km [b], and thus distance difference of 7
| 282 km, and a speed of light of 300mm m /s_
|
| [a]
| https://imagine.gsfc.nasa.gov/features/cosmic/earth_info.htm...
|
| [b] https://en.wikipedia.org/wiki/Earth%27s_circumference
| shagie wrote:
| The relevant RFC is from (April 1st) 1991 - Memo from the
| Consortium for Slow Commotion Research (CSCR)
| https://www.rfc-editor.org/rfc/rfc1217.html
|
| Section 4 deals with Jam-Resistant Underwater Communication
| The ULS system proposed in (2) above has the weakness that it
| is readily jammed by simple depth charge explosions
| or other sources of acoustic noise (e.g., Analog
| Equipment Corporation DUCK-TALK voice synthesizers
| linked with 3,000 AMP amplifiers). An alternative is to
| make use of the ultimate in jam resistance: neutrino
| transmission. For all practical purposes, almost
| nothing (including several light- years of lead) will
| stop a neutrino. There is, however, a slight cross-
| section which can be exploited provided that a cubic mile of
| sea water is available for observing occasional neutrino-
| chlorine interactions which produce a detectable
| photon burst. Thus, we have the basis for a highly
| effective, extremely low speed communication system
| for communicating with submarines.
| JumpCrisscross wrote:
| > _make use of the ultimate in jam resistance: neutrino
| transmission. For all practical purposes, almost nothing
| (including several light-years of lead) will stop a
| neutrino_
|
| Signals aren't jammed by being blocked but overpowered. If
| you want to disrupt someone's neutrino comms, you don't
| start building lead walls. You flood their volume with
| neutrino noise. (I don't know how feasible that is to
| continuously do over a large volume.)
| throwpoaster wrote:
| Got me curious if that's enough margin for HFT firms to
| invest...
| thfuran wrote:
| 24 ms is massive. 0.1 bps makes it tricky to make use of.
| justinclift wrote:
| Maybe they could use a large cluster of beams in
| parallel? :)
| _spduchamp wrote:
| Transmit uncertainty by circumference ahead of time, and
| low bandwidth info that resolves uncertainty through the
| core?
| jvanderbot wrote:
| To be clear: 24 ms is a massive _improvement_ you mean?
| lwansbrough wrote:
| I assume yes considering much of HFT is measured in ns.
| lawlessone wrote:
| Most of those neutrinos will keep going though.
|
| Imagine aliens come some day and ask us "What's with all
| the neutrinos?" :-)
|
| They're either going to be very confused or understand it
| perfectly depending on how their society(ies) work.
|
| Not to mention we'll have to listen to people complaining
| that they have a headache because of neutrinos..
| dhosek wrote:
| --I've become magnetized by the neutrinos! Look, my keys
| stick to my arm!
|
| --Ma'm, that's just because you're sweaty and sweat makes
| your skin sticky.
| lawlessone wrote:
| How soon until some high speed trader figures out this would
| be a faster way to send some data than sending it around the
| earth?
| temp0826 wrote:
| I'd like to imagine this as an early step towards
| omnidirectional point-to-point links blasting through the
| planet at each other to replace the need for
| switching/routing.
| holoduke wrote:
| High frequency traders pay attention please.
| tetris11 wrote:
| Redhat might need to rename their orchestration product
| elashri wrote:
| And while we are at that. Unix communities would make a great
| contribution by changing "root" as the super user account
| convention /s. This will help physicists searching for ROOT
| on the web.
| elashri wrote:
| The concept of near and far detector for a neutrinos experiment
| is not new. We already have NOvA which DUNE will be its
| successor and probably will be able to solve the neutrinos mass
| hierarchy by then.
| aa-jv wrote:
| >a neutrino beam cutting straight through the earth, in a chord
| hundreds of miles long
|
| In my copy of this mental image, I wondered if Earths' gravity,
| and indeed our movement through the cosmos, bends that chord,
| and what it would sound like ..
| wiml wrote:
| Earth's gravity certainly does (though not by much); our
| movement through the cosmos shouldn't appreciably, since the
| Earth is in freefall. (But tides will affect it.)
| hn72774 wrote:
| Is there any current or potential overlap with gravity wave
| science like LIGO?
|
| The article touches on black holes and supernovae. I am curious
| to learn more.
|
| > It will enable scientists to explore new areas of neutrino
| research and possibly address some of the biggest physics
| mysteries in the universe, including searching for the origin of
| matter and learning more about supernovae and black hole
| formation.
| lnauta wrote:
| This is the dream of multi-messenger astronomy:
|
| Simulations show that next generation gravitational wave
| detectors will be able to detect the initial part of the wave
| before the actual merger of objects (or collision?). If you can
| identify this signal in time, you could make the 'regular'
| telescopes look into that particular direction and look for a
| signal in light, and you could use a neutrino detector at the
| same time (think IceCube, KM3NeT, Baikal and others that look
| at large parts of the sky) to look in the neutrino channel.
|
| This way you would have gravitational wave-, light- and
| neutrino-channels from a single object. This is still many
| years (decades?) away, but would be incredible for studying
| exotic objects.
|
| If you mean, measuring the neutrino baseline difference when a
| GW passes through the Earth, perhaps. I never thought about it,
| but its definitely intriguing.
| hn72774 wrote:
| > If you mean, measuring the neutrino baseline difference
| when a GW passes through the Earth, perhaps. I never thought
| about it, but its definitely intriguing.
|
| That's where my mind went. Lasers need a lot of precise
| controls for vibration and such, and neutrinos move through
| matter almost like it doesn't exist. If the emitter and
| detector were on opposite sides of the earth, and gravity
| effects the neutrinos since they have mass, would that
| increase the resolution of a gravity wave detection?
|
| The multi-messenger concept is fascinating too. Seems like
| the volume of discover is going to keep increasing
| exponentially.
| itishappy wrote:
| The main issue I foresee with this plan is getting a useful
| reading. We measure distances with photons by interfering
| them with a known reference. This raises a number of
| problems for neutrinos:
|
| 1. Neutrino reflection. LIGO and LISA use ultra precise
| mirrors. Can we build a neutrino mirror? Could we get away
| with something else instead, say sending beams around
| opposite sides of the Sun to combine them using
| gravitational lensing?
|
| 2. Neutrino interference. Is this a thing? Pretty sure it's
| not a thing.
|
| 3. Neutrino speed. Photons move at the speed of light.
| Neutrinos don't. Since we measure time and convert, we need
| a precise value for neutrino speed, which we currently
| lack.
| lnauta wrote:
| I was just thinking about the distances used: in
| LIGO/VIRGO, the sizes of the chambers is 4 km, and the
| interferometric distance they look for is 10^{-18} m to
| detect a GW.
|
| For the baseline of DUNE we have 1300km, so that would
| mean 10^{-15} m if we do a very simple comparison. (I am
| not that familiar with GW detection!).
|
| Measuring neutrino events at such a resolution would
| seems not realistic currently, as most detector measure
| events at sizes of cm (reactor experiments)- to meters
| (atmospheric / galactic). However, don't discount someone
| coming up with a brilliant insight to actually do this
| measurement. Some things we measure today were thought
| impossible not that long ago, like GWs and the Event
| Horizon black hole image.
| _hark wrote:
| I worked on this experiment as an undergrad ~10 years ago during
| my freshman year! We built a Cherenkov radiation detector,
| focusing magnets, and did tons of simulations.
|
| This is all from memory, but I remember the beamline setup was to
| get protons from the accelerator there, smash them into a target,
| which produced various charged particles which could be focused
| with the magnets, sent down a long pipe where they would decay
| into neutrinos et al. Then, there's a near detector and a far
| detector (far detector deep underground in South Dakota). The aim
| is to measure the neutrino flavors at both detectors to better
| understand the flavor oscillations (and look for asymmetries
| between neutrino/anti-neutrino oscillations, hopefully to help
| explain the matter/antimatter asymmetry in the universe).
|
| The particular bit I worked most on was studying the effects of
| adding an additional solid absorber at the end of the beamline,
| which was needed to absorb all the particles that didn't decay in
| the pipe. It would produce more neutrinos that were unfocused, so
| would affect the near-far flavor statistics (since these would be
| detected at the near detector but not the far since they were
| unfocused, ruining the statistics). It was a great intro to doing
| physics research :-)
| tocs3 wrote:
| I have been watching Amazon and Alibaba for neutrino detectors.
| None so far.
|
| How big is the experiment (outside distance)? It would be great
| to do a giant CAT scan of the Earth.
| scheme271 wrote:
| Neutrinos don't really interact much with other matter so you
| need either a really intense source of neutrinos or a really
| big detector (think multiple tons of stuff ) or both. So you're
| talking about a 10m x 10m volume plus you need the detector to
| be in a place that doesn't get much other radiation so you need
| to bury it a few hundred meters underground.
| dhosek wrote:
| So it's gonna be a special order from Alibaba then?
| fnord77 wrote:
| https://news.uchicago.edu/story/worlds-smallest-neutrino-
| det...
| pjs_ wrote:
| Thirty thousand tons of liquid argon
| johnea wrote:
| This is super nerd interesting and everything, but does this have
| any real effect on everyday life?
|
| I am very supportive of advancing science, but I just wonder if
| this is the top prioriy for spending in the current world...
| kridsdale3 wrote:
| Maybe one day, like faster communication through the planet.
| People were saying the same question you asked about radio
| waves only 100 years ago.
| dang wrote:
| [stub for offtopicness. you're all correct, but it's fixed now]
| ceejayoz wrote:
| I really hope someone on the team has Atreides as a last name.
| snapcaster wrote:
| So jealous they get to call themselves Dune scientists
| hyperific wrote:
| Not Dune as in Arrakis, DUNE as in Deep Underground Neutrino
| Experiment
| KSteffensen wrote:
| Are you absolutely sure there is no Arrakis involved in the
| choosing of that acronym?
| jajko wrote:
| Maybe some Arrak?
| bldk wrote:
| > Dune Scientists from Fermilab
|
| read that three times
| dhosek wrote:
| Sandworms spotted in DuPage County.
| Dansvidania wrote:
| I firmly believe somebody is still giggling about the
| choice of acronym they managed to get approval for.
| CapeTheory wrote:
| The SPICE must flow
|
| (Small Particles Inside the Crust of the Earth)
| nntwozz wrote:
| May their prototype detector never chip and shatter.
| cratermoon wrote:
| Did the automatic headline mangler change "DUNE" the acronym
| for "Deep Underground Neutrino Experiment" to "Dune" the name
| of a heap of sand and also the nickname of a planet in a
| fictional universe?
| layer8 wrote:
| Yes.
| Apocryphon wrote:
| That's what it's been dune
| njarboe wrote:
| The title would be better if the original acronym
| capitalization was kept. "DUNE" not "Dune". I clicked through
| hoping to find out about a collaboration between
| geomorphologists and particle physicists. Still interesting but
| felt like a clickbait title.
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