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TN8211 “Inleiding Elementaire Deeltjes” Twee delen: -Theorie: Paul de Jong -Technologie: Instrumentatie: Harry van der Graaf 1.

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Presentatie over: "TN8211 “Inleiding Elementaire Deeltjes” Twee delen: -Theorie: Paul de Jong -Technologie: Instrumentatie: Harry van der Graaf 1."— Transcript van de presentatie:

1 TN8211 “Inleiding Elementaire Deeltjes” Twee delen: -Theorie: Paul de Jong -Technologie: Instrumentatie: Harry van der Graaf 1

2 Op Maandag 16 Dec Donderdag 9 Jan Donderdag 16 Jan Donderdag 23 Jan Maandag 27 Jan: voor de helft; vragenuurtje -besprekening huiswerk (terugkoppeling) -hoorcollege 1 -hoorcollege 2 -oefening Examen: donderdag 30 januari 9:00 – 12:00 h. Open Boek examen! 2

3 Huiswerk -inleveren -als pdf: mailen naar -vanaf twee dagen voor het volgende college -uiterlijk voor 16:00 h op de dag voor het college -samenwerking in groepen wordt aangemoedigd -maar: strikt individueel inleveren! Huiswerk heeft drie componenten: -terugblik op de stof: makkelijke vragen -vragen waarover je moet nadenken (en slim & creatief mag zijn) -‘examen’ vraag over de stof daarvoor 3

4 Elementary Particles Radiation Technology, Instrumentation 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 4

5 Introduction short history overview The first particles: atoms, electrons, ions The first particle detectors a modern solid-state particle detector 5

6 WimshurstWimshurst’s electricity generator, Leidsche Flesschen History 6

7 Glazen buizen: gasontlading Hoogspanning generatoren (Wymhurst), transformatoren (Rumkorff) Ontdekking radiogolven: 1867 Maxwell (theory) 1887 Heinrich Hertz 1887 Marconi Vacuumpompen Beschikbaarheid (zuivere) gassen Marconi 7

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

9 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 9

10 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 10

11 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 11

12 gnd HV = 10 kV Faraday Cage! belt 12

13 Electrostatic deflection F e = q. E perp Magnetic deflection: Lorentz force F L = q.v.B - + ✪ Electron beam propagates as straight line if: q/m = E perp 2 /(2.V.B 2 )  Constant ratio of mass and charge Definition of electron Lorentz Force 13

14 Relativiteit Hoe kan dat nou? twee electronen twee parallel bewegende electronen v waarnemer meebewegend v of ? alleen statische kracht Lorentz kracht erbij 14

15 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 15

16 16

17 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

18 Radio activity X-rays Henri Bequerel uranium Marie Curie radium, polonium Rutherford: Alfa beta gamma rays Photographic emulsion 18

19 Rutherford atomic model: extreme ratios of E/m Emptyness, nucleon 1905: Einstein/Planck E = h ν: Small dimensions High energy Quantum Mechanics Diameter atom: ~ 1 nm Diameter nucleon: ~ nm Albert Einstein E = h ν = h c/λ E: energy h: Planck’s Constant c: velocity of light λ: wavelength ‘high energy physics’ ‘high’ with respect to ‘classical’ physics Planck's constant = × m 2 kg / s 19

20 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 20

21 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 21

22 Radio activity X-rays Henri Bequerel uranium Marie Curie radium, polonium Rutherford: Alfa beta gamma rays Photographic emulsion 22

23 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 c: velocity of light λ: wavelength ‘high energy physics’ ‘high’ with respect to ‘classica’l physics 23

24 CERN, Geneve Higgs’ particle: 100 – 500 GeV !! 24

25 to Gran-Sasso (730 km) CERN accelerator complex 25

26 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 26

27 Measurement (detection) of particles Ionisation radiation Interaction of radiation with matter Fast charged particles transversing matter 27

28 nπ0γυnπ0γυ μ + μ - π + π - p e charged particles neutral particles 28

29 Energy transfer: mainly to electrons Ionisation: forming elecron-ion pairs Detection of charged (and energetic) particles e- muon (b.v.) 29

30 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) 30

31 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 31

32 Scintillation ZnS scintillator viewed by naked eye Rutherford Experiment scintillatorPhotomultiplier Si avalanche diode 32

33 Cloud Chambers Bubble Chambers Core for growing droplet or bubble ‘made possible’ by ion or electron 33

34 CERN photo, Bubble chamber picture showing delta-rays The red arrows indicate some of the  -electrons, looping in the magnetic field applied 34

35 Bubble chamber photograph shows different bubble density along tracks for different particle momenta and particle type. 35

36 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 36

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