Particle Accelerators
Maciej Trzebiński
Institute of Nuclear Physics Polish Academy of Sciences
Particle Physics Summer Student Programme IFJ PAN, 10th July 2019
M. Trzebiński Particle Accelerators 1/26 How to Observe (in macro-scale)?
M. Trzebiński Particle Accelerators 2/26 How to Observe (in macro-scale)?
Basic ’tool’: our eyes. Resolution: 0.03 mm (about 25 cm from eye).
Resolution How far from each other are objects before they will visually merge.
M. Trzebiński Particle Accelerators 2/26 How to Observe (in macro-scale)?
Basic ’tool’: our eyes. Resolution: 0.03 mm (about 25 cm from eye).
Resolution How far from each other are objects before they will visually merge.
Microscope: visible light – magnification up to 1500x, ultraviolet – magnification up to 3500x.
M. Trzebiński Particle Accelerators 2/26 How to Observe (in macro-scale)?
Basic ’tool’: our eyes. Resolution: 0.03 mm (about 25 cm from eye).
Resolution How far from each other are objects before they will visually merge.
Microscope: visible light – magnification up to 1500x, ultraviolet – magnification up to 3500x.
Observation Conditions The wavelength must be shorter than the size of the object.
M. Trzebiński Particle Accelerators 2/26 How to Observe (in micro-scale)?
Corpuscular-wave Duality Matter has properties of both: corpuscles and waves. In particular, each particle has a corresponding wavelength, which is in inverse proportion to its energy: wavelength ∼ 1/particle energy The higher is the particle energy, the smaller is its wavelength.
M. Trzebiński Particle Accelerators 3/26 How to Observe (in micro-scale)?
Corpuscular-wave Duality Matter has properties of both: corpuscles and waves. In particular, each particle has a corresponding wavelength, which is in inverse proportion to its energy: wavelength ∼ 1/particle energy The higher is the particle energy, the smaller is its wavelength.
Electron microscope: • magnification: 107x • resolution: 50 pm
M. Trzebiński Particle Accelerators 3/26 How to Observe (in micro-scale)?
Corpuscular-wave Duality Matter has properties of both: corpuscles and waves. In particular, each particle has a corresponding wavelength, which is in inverse proportion to its energy: wavelength ∼ 1/particle energy The higher is the particle energy, the smaller is its wavelength.
electron source Electron microscope: • magnification: 107x • resolution: 50 pm
M. Trzebiński Particle Accelerators 3/26 How to Observe (in micro-scale)?
Corpuscular-wave Duality Matter has properties of both: corpuscles and waves. In particular, each particle has a corresponding wavelength, which is in inverse proportion to its energy: wavelength ∼ 1/particle energy The higher is the particle energy, the smaller is its wavelength.
electron source Electron microscope: • magnification: 107x acceleration (energy • resolution: 50 pm increase) in the electric field
M. Trzebiński Particle Accelerators 3/26 How to Observe (in micro-scale)?
Corpuscular-wave Duality Matter has properties of both: corpuscles and waves. In particular, each particle has a corresponding wavelength, which is in inverse proportion to its energy: wavelength ∼ 1/particle energy The higher is the particle energy, the smaller is its wavelength.
electron source Electron microscope: • magnification: 107x acceleration (energy • resolution: 50 pm increase) in the electric field
focusing in the magnetic field
M. Trzebiński Particle Accelerators 3/26 How to Observe (in micro-scale)?
Corpuscular-wave Duality Matter has properties of both: corpuscles and waves. In particular, each particle has a corresponding wavelength, which is in inverse proportion to its energy: wavelength ∼ 1/particle energy The higher is the particle energy, the smaller is its wavelength.
electron source Electron microscope: • magnification: 107x acceleration (energy • resolution: 50 pm increase) in the electric field
focusing in the magnetic field
’illuminating’
M. Trzebiński Particle Accelerators 3/26 How to Observe (in micro-scale)?
Corpuscular-wave Duality Matter has properties of both: corpuscles and waves. In particular, each particle has a corresponding wavelength, which is in inverse proportion to its energy: wavelength ∼ 1/particle energy The higher is the particle energy, the smaller is its wavelength.
electron source Electron microscope: • magnification: 107x acceleration (energy • resolution: 50 pm increase) in the electric field
focusing in the magnetic field
’illuminating’
data readout
M. Trzebiński Particle Accelerators 3/26 Evolution of Particle Accelerators Over the last decades, we have significantly developed particle acceleration techniques. Accelerators can be classified based on: shape: linear (cons.: each element is used only once), circular (cons.: synchrotron radiation). particles used: leptons, e.g. electrons (cons.: significant energy loss because of synchrotron radiation), hadrons, e.g. protons (cons.: particles are not elementary).
M. Trzebiński Particle Accelerators 4/26 Evolution of Particle Accelerators Over the last decades, we have significantly developed particle acceleration techniques. Accelerators can be classified based on: shape: linear (cons.: each element is used only once), circular (cons.: synchrotron radiation). particles used: leptons, e.g. electrons (cons.: significant energy loss because of synchrotron radiation), hadrons, e.g. protons (cons.: particles are not elementary).
Natural units in HEP: Natural units in HEP are those associated with the quantum mechanics and relativity theory scales: action: ~ = 1, speed of light in vacuum: c = 1, energy: eV (electronvolt): Electronvolt – the amount of energy gained (or lost) by the charge of a single electron moving across an electric potential difference of one volt. 1eV = 1e · 1V = 1.602 · 10−19J
M. Trzebiński Particle Accelerators 4/26 How to Observe?
Recipe (micro-scale): accelerate particle to high energy and observe the collision remnants. The more energy is delivered, the more probable production of new, heavy particle is.
M. Trzebiński Particle Accelerators 5/26 How to Observe? Recipe (micro-scale): accelerate particle to high energy and observe the collision remnants. The more energy is delivered, the more probable production of new, heavy particle is. Two types of collisions: particle beam vs. target; maximum energy in the √center of mass (i.e. available for particle production) is 2 × particle mass × beam energy beam vs. beam; max. energy in the center of mass is 2 × beam energy
M. Trzebiński Particle Accelerators 5/26 How to Observe? Recipe (micro-scale): accelerate particle to high energy and observe the collision remnants. The more energy is delivered, the more probable production of new, heavy particle is. Two types of collisions: particle beam vs. target; maximum energy in the √center of mass (i.e. available for particle production) is 2 × particle mass × beam energy beam vs. beam; max. energy in the center of mass is 2 × beam energy
Example the Higgs boson production at the LHC: two partons (proton constituents) interact, because of high energy available, production of new, heavy particles is possible, one of them may be the Higgs boson, production probability (so-called cross-section) in proton-proton collision of 7000 GeV energy is of about 10−10. M. Trzebiński Particle Accelerators 5/26 Cross-section and Luminosity
Cross-section, σ How probable is that a certain process will happen. Unit: barn [b] (cm2).
M. Trzebiński Particle Accelerators 6/26 Cross-section and Luminosity
Cross-section, σ How probable is that a certain process will happen. Unit: barn [b] (cm2).
Luminosity, L How efficient is an accelerator / how much data was collected: luminosity [cm−2·s−1], integrated luminosity [b−1].
Integrated luminosity depends on: collision frequency, f , number of particles in bunch, N, number of bunches, n, width of the beam, σ, data collection time, t. f · n · N · N L = 1 2 · t 4π · σx · σy
M. Trzebiński Particle Accelerators 6/26 Cross-section and Luminosity
Cross-section, σ How probable is that a certain process will happen. Unit: barn [b] (cm2).
Luminosity, L How efficient is an accelerator / how much data was collected: luminosity [cm−2·s−1], integrated luminosity [b−1].
Integrated luminosity depends on: collision frequency, f , number of particles in bunch, N, number of bunches, n, width of the beam, σ, data collection time, t. f · n · N1 · N2 L = · t How many events with the Higgs boson one 4π · σx · σy can expect in 100 fb−1 of data collected by Number of collected events: the LHC at the center of mass energy of √ n = L · σ s = 13 TeV? M. Trzebiński Particle Accelerators 6/26 Research Facility (just one of few)
Conseil Europ´een pour la Recherche Nucl´eaire European Organization for Nuclear Research
CERN: created: 29 September 1954 (decided in 1952), the biggest lab in the world devoted for fundamental research, ∼2600 employees and ∼13000 users (scientists and engineers) from all over the world (∼300 from Poland), Poland @ CERN: observer since 1964 r., member since 1 July 1991, side ’technologies’: www, touch screen, ...
Scientific equipment (of our interest1): accelerator LHC – Large Hadron Collider detectors: ATLAS, CMS, ALICE, LHCb, TOTEM, LHCf, MoEDAL.
1At CERN we have about 60 other experiments: e.g. COMPASS, NA61/SHINE, ... M. Trzebiński Particle Accelerators 7/26 CERN – Conseil Europ´een pour la Recherche Nucl´eaire
M. Trzebiński Particle Accelerators 8/26 Proton Source
Hydrogen bottle (hydrogen = proton + electron) Duo-plazmatron – strips electrons from protons: cathode emits electrons to the vacuum chamber gas intended to be ionized is let in gas is ionized (plasma state) because of interactions with electrons electrons are stripped from the nucleus in the electric field
M. Trzebiński Particle Accelerators 9/26 Hydrogen Bottle adn Duo-Plasmatron
M. Trzebiński Particle Accelerators 10/26 Acceleration
Acceleration is in the electric field!
We have 2 linear accelerators at CERN: LINAC2: since 1978 r.; replaced LINAC1, accelerators protons to 50 MeV, now (LS2) is replaced by LINAC4 (160 MeV). LINAC3: since 1994 r., accelerates ions to 4.2 MeV/nucl., uses about 500 mg of lead for every 2 weeks of running, heavy ions are sent further to Low Energy Ion Ring, will work at least until 2022 r.
M. Trzebiński Particle Accelerators 11/26 LINAC2
M. Trzebiński Particle Accelerators 12/26 Beam Control – magnets
Movement of the beam is in the magnetic field → Lorentz force (magnetic part): F~ = q · (~v × B~ )
Magnet types dipoles – bend particles, quadrupoles – beam focusing / defocusing, multipoles (sextupoles, octupoles, ...) – higher order corrections.
M. Trzebiński Particle Accelerators 13/26 Dipole Magnet
M. Trzebiński Particle Accelerators 14/26 Quadrupole Magnet
M. Trzebiński Particle Accelerators 15/26 Proton Synchrotron Booster
Circular accelerator. 20 m of circumference. Since 1972. Accelerates protons from 50 MeV to 1.4 GeV. Before the booster was installed, protons were injected directly to the Proton Synchrotron. This was limiting the number of protons by two orders of magnitude compared to booster.
M. Trzebiński Particle Accelerators 16/26 PS Booster
M. Trzebiński Particle Accelerators 17/26 Proton Synchrotron
Second oldest accelerator at CERN (since 1959). 628 m of circumference. 277 electromagnets, incl. 100 dipoles. Accelerates 1.4 GeV protons from PS Booster to 26 GeV or heavy ions from LEIR (72 MeV/nucl.) to 5.9 GeV/nucl.
M. Trzebiński Particle Accelerators 18/26 Proton Synchrotron
M. Trzebiński Particle Accelerators 19/26 Super Proton Synchrotron
Circular accelerator started in 1976. 6.9 km of circumference. 1317 electromagnets, incl. 744 dipoles. Accelerates protons to energy of 450 GeV or heavy ions to energy of 177 GeV/nucl. Delivers beams to the LHC, test-beams and NA61/SHINE, NA62 and COMPASS experiments. Studies of proton-antiproton collisions at the SPS lead to discovery of: W and Z bosons; UA1 and UA2 experiments; Nobel prizes for Carlo Rubbia and Simon van der Meera, direct CP breaking; NA48 experiment.
M. Trzebiński Particle Accelerators 20/26 Super Proton Synchrotron
M. Trzebiński Particle Accelerators 21/26 Large Hadron Collider
The most powerful accelerator built (so far): 27 km of circumference. Started in w 2008. Superconducting electromagnets: 1232 dipoles and 858 quadrupoles. Temperature of magnets: 1.9 K (-271.3 0C). Magnetic field: (up to) 8.33 T. Ultra-high vacuum 10−13 atm. accelerates protons to 14 TeV or heavy ions to 2.76 GeV/nuxl. Particles are accelerated to 0.999999991 × c. Proton-proton lead to the discover of the Higgs boson; ATLAS and CMS experiments; Nobel prize for Francois Englert and Peter Higgs in 2013.
M. Trzebiński Particle Accelerators 22/26 Large Hadron Collider
M. Trzebiński Particle Accelerators 23/26 Zderzenia Wiązek
M. Trzebiński Particle Accelerators 24/26 Animation – Sources
Used in this lecture: Dipole magnet: http://cds.cern.ch/record/1750706 Quadrupole magnet: http://cds.cern.ch/record/1750723 CERN: http://cds.cern.ch/record/1750715 Duoplazmatron: http://cds.cern.ch/record/1750714 LINAC2: http://cds.cern.ch/record/1750713 PS Booster: http://cds.cern.ch/record/1750712 Proton Synchrotron: http://cds.cern.ch/record/1750711 SPS: http://cds.cern.ch/record/1750710 LHC: http://cds.cern.ch/record/1750708 Collisions: http://cds.cern.ch/record/1750703 Additional: Shape of the beam: http://cds.cern.ch/record/1750709 Beam profile: http://cds.cern.ch/record/1750707 Collimators: http://cds.cern.ch/record/1750704 ATLAS detector: http://cds.cern.ch/record/1483758
M. Trzebiński Particle Accelerators 25/26 Additional Materials
Scale of the Universe: http://htwins.net/scale2/ Particle physics: http://particleadventure.org/index.html CERN Accelerator School (basic): http://cas.web.cern.ch/cas/CzechRepublic2014/Lectures/Lectures.html CERN Accelerator School (advanced): http://cas.web.cern.ch/cas/Poland2015/Lectures/Polandlectures.html H. Wiedemann, Particle Accelerator Physics, ph381.edu.physics.uoc.gr/Particle Accelerator Physics.pdf
M. Trzebiński Particle Accelerators 26/26