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Elementary Particles Instrumentation Introduction Dec 15, 2014 Radiation detection Accelerators (Relativity!) Particle Physics experiments Fixed Target.

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Presentation on theme: "Elementary Particles Instrumentation Introduction Dec 15, 2014 Radiation detection Accelerators (Relativity!) Particle Physics experiments Fixed Target."— Presentation transcript:

1 Elementary Particles Instrumentation Introduction Dec 15, 2014 Radiation detection Accelerators (Relativity!) Particle Physics experiments Fixed Target experiments Collider experiments astro-particle physics new physics: dark matter Medical radiation: Medical imaging Radiation therapy, beam therapy Nuclear power (fusion, fission) veel demo’s! Instrumentatie: niet moeilijk, wel veel 1

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

3 WimshurstWimshurst’s electricity generator, Leidsche Flesschen History 3

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

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

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

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

8 From: Principles of Charged Particle Acceleration Stanley Humphries, Jr., on-line edition, p Van de Graaff accelerator Vertical construction is easier as support of belt is easier Corona discharge deposits charge on belt Left: Robert van de Graaff 8

9 gnd HV = 10 kV Faraday Cage! belt 9

10 Electrostatic deflection F e = q. E Magnetic deflection: Lorentz force F L = q.v.B - + ✪ Electron beam propagates as straight line if: q/m = E 2 /(2.V.B 2 )  Constant ratio of mass and charge Definition of electron Lorentz Force 10

11 Relativiteit Hoe kan dat nou? twee electronen twee parallel bewegende electronen v waarnemer meebewegend v of ? alleen statische kracht Lorentz kracht erbij 11

12 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. trein staat stiltrein beweegt t.o.v. stilstaande waarnemer erboven Tweelingparadox Lorentzcontractie 12

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 13

14 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 E 2 = m o 2 c 4 + p 2 c 2 [classic: E = ½ mv 2 ] With:  = v / c, and the Lorentz factor γ: relativistic mass m r = γ m 0 γ = 1 / sqrt(1-  2 ), and  = sqrt(γ 2 -1) / γ So: total energy E = m 0 c 2 sqrt(1+  2 γ 2 ) [= rest mass energy eq. + kinetic energy] = γ m 0 c 2 = m r c 2 14

15 Radio activity X-rays Henri Bequerel uranium Marie Curie radium, polonium Rutherford: Alfa beta gamma rays Photographic emulsion 15

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

17 17

18 X-ray tube: accelerate electrons with a voltage of typically 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 Wilhelm Conrad Roentgen Nobel Prize

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: ~ nm Albert Einstein E = h c/λ E: energy h: Planck’s Constant = 6.62 x Js c: velocity of light λ: wavelength ‘high energy physics’ ‘high’ with respect to ‘classica’l physics 19

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

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

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 22

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

24 nπ0γυnπ0γυ μ + μ - π + π - p e charged particles neutral particles 24

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

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) 26

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 27

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

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

30 CERN photo, Bubble chamber picture showing delta-rays The red arrows indicate some of the  -electrons, looping in the magnetic field applied 30

31 Bubble chamber photograph shows different bubble density along tracks for different particle momenta and particle type. 31

32 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 32

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