The Alpha Magnetic Spectrometer (AMS) on the International Space Station
This is a modal window.
The media could not be loaded, either because the server or network failed or because the format is not supported.
Formal Metadata
| Title |
| |
| Title of Series | ||
| Number of Parts | 340 | |
| Author | ||
| License | CC Attribution - NonCommercial - NoDerivatives 4.0 International: You are free to use, copy, distribute and transmit the work or content in unchanged form for any legal and non-commercial purpose as long as the work is attributed to the author in the manner specified by the author or licensor. | |
| Identifiers | 10.5446/45021 (DOI) | |
| Publisher | ||
| Release Date | ||
| Language |
Content Metadata
| Subject Area | ||
| Genre | ||
| Abstract |
|
00:00
TypesettingMorningDrehmasseYearParticle physicsInternational Space StationPhysicistLecture/Conference
00:48
International Space StationMagnetismSpace stationInternational Space StationFlow measurementDrehmasseComputer animationLecture/Conference
01:18
International Space StationMagnetismSensorElementary particleAccelerator mass spectrometryParticle physicsSpectrometerDrehmasseSensorCosmic rayLoudspeakerLecture/ConferenceComputer animationMeeting/Interview
01:41
Cartridge (firearms)MagnetRestkernAtomic nucleusScintillatorSpectrometerAnalemmaChandrasekhar limitGamma rayLightNeutrinoGreySatelliteMetreStellar atmosphereSensorAccelerator mass spectrometryNeutrinoLightStellar atmosphereSensorJuli FernándezCosmic rayMagnetGreyColor chargeMagnetic coreWater vaporStandard cellCell (biology)NeutrinoSpectrometerGround (electricity)Lecture/Conference
02:58
ObservatoryColor chargeCosmic rayLeadIceParticle showerParticle physicsTARGET2NeutrinoFACTS (newspaper)Stellar atmosphereSizingMeasurement
03:41
NeutrinoParticle physicsAccelerator mass spectrometryDark matterGalaxyVisibilityUniversePositronCollisionMeasurementPositronElectronRegentropfenCollisionIceSensorDark matterNeutrinoCosmic rayNeutrinoMassAntiprotonUniverseAustria-Mikro-Systeme International GmbHGalaxyDipolControl roomVisible spectrumMagnetic coreSynthesizerNeutralinoFinger protocolPower (physics)KontraktionComposite materialYearParticle physicsSpeckle imagingSpare partDrehmasseAccess networkStarComputer animation
06:01
MeasurementSensorRadiationCalorimeterElectromagnetic spectrumElectronSpectrometerFlow measurementShip classRailroad carElementary particleAmplitude modulationColor chargeDrehmasseDaySynthesizerParticle physicsMagnetRainCosmic rayGentlemanSpeckle imagingCounter (furniture)MeasurementChemical substanceCogenerationThermalSiliconÜbergangsstrahlungSensorFlightRing (jewellery)
07:14
DimmerPhysicistAccelerator mass spectrometryParticle acceleratorCalibrationYearCosmic rayGirl (band)SensorCERNDark matterLecture/Conference
08:14
CollisionAccelerator mass spectrometryTurningDark matterPulsarPlain bearingMeasurementCougarTramCasting defectCollisionSpare partQuality (business)Ship naming and launchingGentlemanCosmic rayRemotely operated underwater vehiclePlain bearingDark matterLecture/Conference
08:59
CollisionPositronFord ExplorerRegentropfenEnergiesparmodusCosmic rayForceKerr-EffektPlanetComposite materialRemotely operated underwater vehiclePositron
09:44
Model buildingDark matterSource (album)PositronLumberMeasurementAccelerator mass spectrometryLarge Hadron ColliderAnnihilationLepus (constellation)Particle physicsElectronMint-made errorsApparent magnitudeAirbus A300Ford CapriVisible spectrumSupernovaCosmic rayCollisionGreen politicsRestkernNeutralinoSource (album)Spare partMagic (cryptography)Juli FernándezYearShip breakingFood storageMagnetic coreCylinder headReaction (physics)NegationTape recorderRailroad carCompound engineMeasurementGentlemanPower (physics)Order and disorder (physics)FACTS (newspaper)TypesettingFormation flyingPositronAccess networkVisible spectrumBarrelFlightSizingMaskRainMassAmplitude modulationDark matterMint-made errorsParticle physicsHiggs bosonParton (particle physics)Austria-Mikro-Systeme International GmbHElectronNeutrinoRRS DiscoveryWeinberg-Salam-TheorieModel buildingElementary particlePulsarTauEnergiesparmodusLecture/Conference
15:53
Accelerator mass spectrometryVisible spectrumElementary particleParticleDark matterPulsarKette <Zugmittel>CollisionCosmic microwave background radiationLungenautomatOrbital periodMeasurementRestkernSauerstoff-16LightAtomic nucleusParticle physicsUniverseSensorColor chargeStellar atmosphereAntiparticleAntiprotonTypesettingElementary particleSensorMeasurementColor chargeRadioactive decaySauerstoff-16Big BangInterstellar mediumGround (electricity)Amplitude modulationVisible spectrumCollisionCosmic microwave background radiationDark matterUniverseMoving walkwaySpare partFlow measurementMeasuring instrumentCosmic rayPositronElectronWater vaporBicycleQuality (business)Railroad carGreyCartridge (firearms)TelephonePaperOrder and disorder (physics)FlightMopedMusical ensembleMonthStarMagnetic coreLight
22:02
Dark matterPositronElectronAccelerator mass spectrometryMeasurementSpace stationSpace probeTelephoneAutomobile platformSound recording and reproductionRestkernModel buildingComposite materialStarSpace stationMeasurementSpace ShuttleLoudspeakerComputer animation
23:03
ToolParticle acceleratorAccelerator mass spectrometrySpace probeVideoRRS DiscoveryLoudspeakerNightSynthesizerAutumnSpeckle imagingSensorMeasurementAngeregter ZustandAccelerationYearToolMinute
23:45
Interface (chemistry)Crystal structureMinuteHourComputer animation
24:12
TowingVakuumphysikThermalComputer animation
24:33
Computer animation
24:53
Space Shuttle
25:17
BecherwerkWeightRailroad carRail profile
25:54
VideoElectric power distributionNanotechnologyCommercial vehicleMaterialSpace stationComputer animation
Transcript: English(auto-generated)
00:16
Good morning. When the chairman mentioned I received an Nobel Prize in 1976, it suddenly
00:26
reminded me first time I was here. I met Heisenberg, Dirac, and it's been many years since my wife and I come here and met a new set of distinguished physicists.
00:47
What I'd like to do today is share with you a particle physics experiment on the International Space Station. The International Space Station from one end to another end, from here to
01:02
here is 110 meters, from here to here it's 80 meters, it weighs 420 tons, and the construction cost is about 10 to the 11 dollars. On the space station at this moment there's a magnetic
01:24
spectrometer, a particle physics detector. It is a precision physics detector to measure charged cosmic rays and study their characteristics. Let me mention the beginning of this field
01:44
is done by the previous speaker, George. You probably remember this, your first experiment. On the third cosmic ray antimatter in July, published in Physical Review Letters July
02:02
75, and that was the first time people have the vision to study charged cosmic rays with a magnetic spectrometer, and this is a superconducting magnet. It's really a pioneering for this field. There are two kinds of cosmic rays traveling through
02:22
space. Neutral cosmic rays, light rays and neutrinos can be measured with satellites, large ground-based, and underground detectors. Charged cosmic rays, the Earth's atmosphere is equivalent to 10 meters of water, and imagine space measured directly the original
02:46
property of charged cosmic rays. Underground, only the energy of charged cosmic rays can be studied by summing up their showers. So this is a very famous, very successful
03:02
experiment led by Nobel laureate James Cronin, and that is to measure the energy of charged cosmic ray shower with pure OJ laboratory. Using the fact charged cosmic ray in the atmosphere produce many showers, so you have many, many detectors, measure the showers, summing
03:24
up the showers, you know the total energy. So this is the size of the detector, 68 kilometer by 68 kilometer, and for comparison, this is the size of city of Paris, and it is located in Argentina. Another very impressive experiment is to study extremely high energy
03:47
neutrinos with ice cubes. And this is their control room in the south pole. It is 1.4 kilometer below the ice. It's one kilometer by one kilometer by one kilometer,
04:05
and it has 5,160 detectors. So what are the physics one can learn from AMS? Let me present
04:21
you a few examples. One is the search of the origin of dark matter. We all know more than 90 percent of the matter in the universe is not observable, because you cannot see the core dark matter. The galaxy as seen by the telescope will look like this, but
04:42
if you could see dark matter in the galaxy, the galaxy may look like this. You cannot see dark matter, but collision of dark matter, then we call it neutrino, produce energies which turn into ordinary matter, such as positrons or antiprotons. This
05:06
axis of positrons can be accurately measured by AMS. The axis of positrons is measured called positron fraction, namely the number of positrons normalizes the total number
05:22
of electron positrons. So if you plot the positron fraction as function of positron electron energy, you have a ray produced by collision of ordinary cosmic rays. But if neutrino or dark matter really exist, collision of neutrino produces positrons,
05:46
so you have spectrum like this. And the characteristics depends on the mass, and because the mass is finite, at higher energies, you have a sharp drop off. So this is the
06:04
AMS detector. It's 5 meter by 4 meter by 3 meter, weighs 7.5 tons. It was assembled and tested with a very strong thermal support. It is a chilling electron volt particle
06:21
physics detector. Cosmic rays are characterized by their charge, energy, or momentum. So the top is something called transition radiation detector, and there are nine layers of silicon detector, and the bottom electromagnetic calorimeter, and two layers of thermal flight detector,
06:44
and this is a magnet, and this is a ring image chemical counter. So this, this, this, this, and this, all measure energy and charge. So energy and charge are measured independently
07:01
by four detectors. For experiment in space, you always need to remember, if something goes wrong, you cannot send a graduate student to fix it. So it is an international collaboration with many countries, many institutes, many physicists, and we have very strong support
07:25
from CERN, and from the United States Department of Energy, and from space agencies in the United States, in Europe, in Italy, in Germany, and in China. Before we went into space, the most important thing we did was to test the detector extensively at the
07:45
CERN accelerator, so we know what the response should be once it's in space. So we're sent to space on May 16, 2011, and five years in space, we have collected 80 billion
08:03
cosmic rays up to the energy of one trillion electron volt. So let me show you examples of some physics results. One is the search for origin of dark matter. I already mentioned
08:21
collision for ordinary cosmic ray will produce a curve like this as function of energy. The collision of dark matter will produce curve like this. So this is our first measurement, the red points are data, awfully close to collision of dark matter.
08:44
So this gets newspaper people very excited from New York Times, from Wall Street Journal in Germany, and in France. Everybody says, we have seen dark matter. Not so. So now
09:02
we have new results on positron fraction based on 11 million cosmic rays. Before this experiment, normally people talk about few hundred, and this is 11 million. With 11 million, you can examine the following. First, a low energy, the red curve and the green curve must
09:23
agree with each other. Otherwise, you don't know what you are doing. Second thing is the rate of increase must agree with the model, and a curve like this must have a turning point. So the force must drop down very quickly because of conservation
09:43
of energy. So the first property, the energy at which it began to increase. So this is collision of ordinary cosmic rays. Indeed, a very low energy, this is all measure data, agreed with collision of ordinary cosmic rays. But this energy suddenly goes
10:05
away. This deviation from traditional understanding of collision of cosmic rays shows the existence of something new has happened. We don't know what it is, but something new has happened. Second, with 11 million events, you really see very good agreement with
10:27
collision of dark matter at very high energy. But you can also produce astrophysics sources to explain this data. The third, with this positive fraction, you can measure its slope,
10:46
the rate of change. You see the rate of change increases, flatten out, then drop to zero. When the slope goes to zero, means you have found a turning point. The maximum has been found. From now on, you will go down. What has not been settled is how quickly
11:07
it can go down. So we have measured up to here, and it would take a few more years to go to the highest energy because the rate is quite low. If it's dark matter model because of conservation of energy, you will go down quickly. If it's a pulsar, a light
11:28
ray goes in a strong magnetic field, produces electron-positron pairs. So a pulsar will show a curve like this. So it will take a few more years to resolve the last part.
11:42
Let me mention, there are three independent methods to search for dark matter. The traditional method is called scattering. You do an experiment underground, make sure neutrino only come in, you go to, you put a nuclei, you detect a record. And this is the traditional way
12:03
people do search for dark matter. And then, at LHC, you do proton-proton, produce neutrino. In space, you do neutrino-neutrino, produce positron-electrons. These three
12:21
orthogonal methods are not correlated to each other. You can visualize this, but look at the physics of the electron-proton. Electron-proton for scattering, electron-proton scattering, leading to the discovery of partons and electroweak theory. Production from proton-proton
12:45
go to electron-positron pair in many laboratories leading to fourth core, fifth core, Z, W, and Higgs. Analyzing, electron-positron go to particles leading to psi and tau-leptons.
13:03
All these were awarded the Nobel Prize. The fact you do not see tau in proton-proton collision does not mean it does not exist. Therefore, if you do not see one reaction in here, does not mean it does not exist. Let me then share with you some interesting
13:25
results. And these are the electron-positron spectra before AMS. On this axis is the electron spectrum, and these are the measurements in green. On this axis is the positron spectrum in red, but many, many experiments. These were the best measurements over the last
13:44
hundred years. The data has large errors and not always in agreement with each other. Because of this large error, you created many theoretical models. This is AMS result.
14:00
This is the electron spectrum, and this is the positron spectrum. Positron is on this axis, electron on this axis. The data clearly exhibit different behavior between electron and positron, not only the magnitude, but most importantly, functional
14:21
behavior. And then we also measure protons. Protons are the most abundant cosmic rays. These were the many, many measurements over the last hundred years, and because the errors are so large, you created many, many models. This is the measurement from AMS, and the
14:44
accuracy in absolute value is 1 percent. Based on 300 million events, and this is the measurement as function of rigidity. Rigidity means momentum per unit charge. The flux goes up, goes down, suddenly changes behavior.
15:05
The conclusion is the red point is our measurement, and this is the traditional assumption the spectrum is power law. But the data agree with the theory until this point, and
15:21
then it breaks away, means you have new unexpected phenomena. This is the measurement of helium before AMS, and the many, many measurements. Helium are the most, second most abundant cosmic rays, are mostly produced in supernovas.
15:41
So they were the best data over the hundred years. The data has very large errors, and therefore not consistent. This is the measurement from AMS, because we have seven independent detector, extensively calibrated, and so we know we can measure the spectrum to an accuracy
16:03
of 1 percent. This is based on 50 million events. The data again disagrees with traditional assumption you have unexpected new phenomena as function of rigidity. The most surprising result, and this will be published soon,
16:27
is the antiprotons. So this is the spectrum of elementary particles in space. Of all the elementary particles, there are only four travel through space, and that
16:40
is electrons, positrons, protons, antiprotons for charged particles, because they have infinite lifetime. The others decay quickly. Of all four, three of them, antiprotons, positrons, and protons, have the exact same energy dependence. And this is the rate,
17:06
and this is the function of rigidity. This is the proton flux, and this is the antiproton flux, this is the positron flux. The absolute value is different, but the function of behavior is exactly the same. And you can look, antiproton to proton, flux to
17:26
basically as a zero slope. And similarly, for antiproton to positron, proton to positron, this somehow behave exactly the same. This axis of antiproton over collision of ordinary
17:45
cosmic ray, it's a very important thing, because this axis cannot be explained from protons. A proton does not produce the proton antiproton pair in a strong magnetic field. So some new explanation is necessary. So for all the elementary particles traveling
18:08
through space, antiproton, positron, proton, have exactly the same energy dependence, but the electron is different. Very curious effect, up to 20 electron volt.
18:24
Now, to search for the origin of dark matter, I mentioned the collision of dark matter produce positrons, antiprotons, and these must be detected above the background from collision of ordinary cosmic rays. So now, you study the signal, the next
18:44
thing you need to do is to look the background, to look the property of ordinary cosmic rays. So the first thing you need to do is to measure the periodic table in space. We know periodic table on the ground, and so you better make sure your detector
19:04
can map out all the periodic table to a high accuracy. So this is the measurement of lithium, the red points, the AMS data, and these are the previous measurements. And lithium, again, cannot be agreed with traditional interpretation.
19:25
You have new phenomena. And this is the measurement of carbon, compared with the previous measurement. And this is the measurement of nitrogen. Previously,
19:41
people see structures, and we do not see that. And these are accurate to 1%. So there are two kinds of cosmic rays produced from the sources, called primary, interact with interstellar media, called secondary. So oxygen is primary, this is an absolute
20:04
measurement. And this nitrogen, part of the primary, part of the secondary, boron, complete secondary. You see they're characteristically different from each other. So that is where we are. We search for dark matter. Now, another example, we search for
20:27
existence of antimatter, something started by George in 75. So the Big Bang origin of the universe required matter and antimatter to be equally abundant at the very hard beginning.
20:43
So we want to look where is the universe made out of antimatter. In the universe, we see helium, carbon, or the periodic table, which I already showed. The question is, is it somewhere far away, the antimatter universe, filled with anti-helium,
21:06
anti-carbon? The type of antimatter universe, cosmic antimatter, cannot be detected by earth because matter and antimatter will annihilate each other. We are living under
21:22
10 meters of water. Matter and antimatter has opposite charge, so we need a magnetic detector to measure the charge of the antimatter. A positive go one way, a negative go the opposite way. To do that, the first thing you need to do to understand
21:41
your instrument and you produce the periodic table for all of them, we have done. We now have 80 billion events, and by the time we start with 100 billion events, we will begin to look for the antimatter. So the latest MS measurement on positive fraction,
22:10
positive, protons, helium, and other nuclei is providing new, precise, unexpected results.
22:21
Now our measurement will produce previous results and has been predicted by previous models. So once it's on the space station, you stay there because there's no more space shuttle to bring you back, so you stay there forever for the lifetime of the
22:46
space station. And so we will continue our accurate measurement to look how quickly it drops down and then search for existence of antimatter and search for new phenomena.
23:02
Like the previous speaker just mentioned, Cosmos is the ultimate laboratory. Cosmos can be observed at energy higher than any accelerator. But the most exciting objective
23:20
of MS to probe the unknown so far or our measurement do not reproduce previous measurement. But the search for phenomena which exist in nature, we have not yet imagined nor have the tool to discover it. Now let me show you a video how this detector is assembled.
23:42
Could I please have the video? This is to reduce 16 years into 3 minutes. The European
24:30
Space Agency to do tests, simulate the space condition. Go to a thermal vacuum chamber,
24:40
test in the test beam, test in 2000 directions, send to Kennedy Space Center. This is in
25:01
Kennedy Space Center. This is to make sure it fits into the space shuttle. This is inside the space shuttle, send to space. The total weight is 2000 tons at lift
25:40
route to carry 7.5 tons to space. Just take us off, put on the space station,
26:05
install on the space station. Okay, that's fine. Thank you. You can stop now. Okay, thank you.
Recommendations
Series of 43 media