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Elementary Particles Instrumentation Introduction Dec 18 , 2018 Radiation detection

Elementary Particles Instrumentation Introduction Dec 18 , 2018 Radiation detection Accelerators (Relativity!) Particle Physics experiments Fixed Target experiments Collider experiments astro -particle physics new physics: dark matter Gravitational Waves Medical radiation:

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Elementary Particles Instrumentation Introduction Dec 18 , 2018 Radiation detection

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  1. Elementary Particles Instrumentation Introduction Dec 18, 2018 Radiation detection Accelerators (Relativity!) Particle Physics experiments Fixed Target experiments Collider experiments astro-particle physics new physics: dark matter Gravitational Waves Medical radiation: Medical imaging Radiation therapy, beam therapy Nuclear power (fusion, fission) veel demo’s! Instrumentatie: niet moeilijk, wel veel

  2. Introduction short history overview The first particles: atoms, electrons, ions The first particle detectors a modern solid-state particle detector

  3. History Wimshurst’s electricity generator, Leidsche Flesschen

  4. Glazen buizen: gasontlading Hoogspanning generatoren (Wimhurst), transformatoren (Rumkorff) Ontdekking radiogolven: 1867 Maxwell (theory) 1887 Heinrich Hertz 1890 Marconi Vacuumpompen Beschikbaarheid (zuivere) gassen: scheikunde Marconi

  5. First accelerator: cathode ray tube J.J. Thomson

  6. Efield = V / D • With electron charge q: • F = q . Efield • electron kinetic energy: • Ee- =  F dD = q.V • Ee- independent of: • distance D • particle mass heated filament distance D Potential diffence V Ee- = q.V (Joule) Ee- = V (eV)

  7. ElectronVolt: eV Energy unit: ElectronVolt: eV 1000 eV = 1 keV 1000 MeV = 1 GeV 1000 GeV = 1 TeV 1 eV = |q| Joules = 1.6 x 10-19 Joules

  8. First accelerator: cathode ray tube J.J. Thomson

  9. Lorentz Force - Electrostatic deflection Fe = q. E + Magnetic deflection: Lorentz force FL = q.v.B ✪ Electron beam propagates as straight line if: q/m = E2/(2.V.B2) Constant ratio of mass and charge Definition of electron

  10. v v of twee electronen ? twee parallel bewegende electronen waarnemer meebewegend alleen statische kracht Lorentz kracht erbij Relativiteit Hoe kan dat nou?

  11. Van de Graaff accelerator Vertical construction is easier as support of belt is easier Corona discharge deposits charge on belt From: Principles of Charged Particle Acceleration Stanley Humphries, Jr., on-line edition, p. 222. http://www.fieldp.com/cpa/cpa.html Left: Robert van de Graaff

  12. Faraday Cage! HV = 10 kV gnd belt

  13. Lorentz Transformation Albert Einstein’s Special Theory on Relativity • Speed of light c is invariant for coordinate transformations z’ = z+vt • time definition varies with coordinate transformation Snel in te zien via experiment in trein: Klok, gemaakt van twee spiegels. Tweelingparadox Lorentzcontractie trein staat stil trein beweegt t.o.v. stilstaande waarnemer erboven

  14. Lorentz Transformation Albert Einstein’s Special Theory on Relativity • Speed of light c is invariant for coordinate transformations z’ = z+vt • time definition varies with coordinate transformation

  15. From Einstein’s Special Theory on Relativity: • For moving particle (‘system’ of just one moving particle!) • Total Energy (of system) = Kinetic Energy + Rest Mass eq. Energy • E2 = mo2 c4 + p2c2 [classic: E = ½ mv2 ] • With: • = v / c, and the Lorentz factor γ: relativistic mass mr = γ m0 γ = 1 / sqrt(1- 2), and  = sqrt(γ2 -1) / γ So: total energy E = m0c2 sqrt(1+ 2γ2) [= rest mass energy eq. + kinetic energy] = γ m0c2 = mrc2 • ******************************************************* • !!! Note: Kinetic Energy is NOT equal to ½ mv2 !!! • *******************************************************

  16. Radio activity X-rays Henri Bequerel uranium Marie Curie radium, polonium Rutherford: Alfa beta gamma rays Photographic emulsion

  17. Rutherford, Manchester 1906 First particle detector ZnS scintillator: light flashes visible with naked eye (+microscope)

  18. Wilhelm Conrad Roentgen Nobel Prize 1901 • X-ray tube: • accelerate electrons with a voltage of typically 20 - 100 kV • and stop them in the anode • electrons radiate in the strong electric field of the (heavy, e.g. W) atomic nuclei ("Bremsstrahlung") in the anode -> generation of X-rays • Most of the energy of the electrons is converted into heat -> anode may need to be cooled (water cooling) and/or to be rotated • Low energy X-rays can be removed by passing the X-rays through a suitable material

  19. Rutherford atomic model: extreme ratios of E/m Emptyness, nucleon Einstein/Planck E = h ν: Small dimensions High energy Quantum Mechanics Diameter atom: ~ 1 nm Diameter nucleon: ~ 10-4 nm E = h c/λ E: energy h: Planck’s Constant = 6.62 x 10-34 Js c: velocity of light λ: wavelength Albert Einstein ‘high energy physics’ so: 1 μm corresponds to order 1 eV ‘high’ with respect to ‘classical’ physics

  20. CERN, Geneve Higgs’ particle: 100 – 500 GeV !!

  21. CERN accelerator complex to Gran-Sasso (730 km)

  22. Natural radioactivity Uranium, Radon, Thorium ‘induced’ radioactivity: irradiation with neutrons, protons, gamma’s Particle Physics/High Energy Physics experiments accelerators fixed target experiments collider experiments

  23. Measurement (detection) of particles Ionisation radiation Interaction of radiation with matter Fast charged particles transversing matter

  24. μ+μ - π+π- p e charged particles n π0 γ υ neutral particles

  25. Detection of charged (and energetic) particles e- muon (b.v.) Energy transfer: mainly to electrons Ionisation: forming elecron-ion pairs

  26. Essential (in gas): - creation of electron-ion pairs - number of clusters per mm tracklength - number of electrons per cluster specific for gas(and density ρ, thus T, P!, and work function W)

  27. Ionisation scintillation (followed by light detection) electron-ion pairs: charge separation, charge signals in gas, in semiconductors photographic emulsions: blackening cloud chambers bubble chambers Detection of non-charged (neutral) particles: - conversion to charged particle (e-, proton) - detection of charged particle

  28. Scintillation ZnS scintillator viewed by naked eye Rutherford Experiment scintillator Photomultiplier Si avalanche diode

  29. Cloud Chambers Bubble Chambers Core for growing droplet or bubble ‘made possible’ by ion or electron

  30. Schatting totale energie uit grootte (oppervlak) van shower eV

  31. Lorentzcontractie: Aarde (en atmosfeer) lijkt veel kleiner voor energetisch muon. Mo muon = 105.658369(9) MeV/c2

  32. Bubble chamber picture showing delta-rays The red arrows indicate some of the d-electrons, looping in the magnetic field applied CERN photo, http://weblib.cern.ch/Home/Media/Photos/CERN_PhotoLab/?p=

  33. Bubble chamber photograph shows different bubble density along tracks for different particle momenta and particle type. http://physics.hallym.ac.kr/education/hep/adventure/bubble_chamber.html

  34. Gaseous Detectors Spark Chamber Passing charged particle detected by sci HV is put over even/odd plates Charge separation (electrons-ions) Electron Avalanche (breakdown, spark) Visible light from exited He/Ne atoms

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