introduction to particle accelerators - ceric · introduction to particle accelerators ... elettra...

PaGES 2 è finanziato dalla Regione Autonoma Friuli Venezia Giulia, nell’ambito del Piano regionale per il potenziamento dell’offerta formativa (POF), anno 2016/2017: Progetto Speciali.

Introduction to Particle Accelerators

With Focus on Synchrotron Light Sources

Simone Di Mitri

Elettra Sincrotrone Trieste

University of Trieste, Dept. of Physics

simone.dimitri@elettra.eu

Ingredients Charged particles: electrons, protons, ions, anti-particles

Static and time-varying electric field increases the particle kinetic energy.

Static and time-varying magnetic field bounds the particle inside the vacuum chamber.

Radiofrequency (RF) accelerating structures

Magnetic elements for controlling the particles direction (orbit) and beam size (focusing).

Special Relativity is all we need. Includes kinematics and dynamics of relativistic charged particles. BvEqFL

2

0cmvE

simone.dimitri@elettra.eu

Why High Energy Particle Beams ?

3

incidreaz EE ~

“Colliders” (LHC,…)

“Synchrotron Light Sources” (Elettra,…)

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Acceleration, Particle Energy

4

VqsEqsFL

Energy E

v

Electric field

V

E= -qV

J = N x m = C x V

1 eV (electronvolt) = 1 e x 1 V e = -1.6e-19 C

Few MeVs protons, Cockroft and Walton, CERN 40’s

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eV

Livingstone Chart

5

Average 10-fold increase in energy every 6 years.

New branches correspond to technological advances.

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Synchrotron Radiation

6

mR

GeVEkeVU

b

turn

4

5.88

E

U

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Synchrotron Light Source

7

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Elettra Sincrotrone Trieste

8

Elettra Sincrotrone Trieste is a nonprofit shareholder company of Italian national interest, established in 1987 to construct and manage synchrotron light sources as international facilities.

ELETTRA Synchrotron Light Source: Beam energy up to 2.4 GeV, 800 proposals from 40 countries

FERMI@Elettra FEL: 100 – 4 nmSponsors:

Italian Minister of University and Research (MIUR)

Regione Auton. Friuli Venezia Giulia

European Investment Bank (EIB)

European Research Council (ERC)

European Commission (EC)

Collaborations:

and many others…

simone.dimitri@elettra.eu

Elettra Synchrotron Light Source

9

Main Ring

Dipole Magnet

B

Quadrupole Magnet RF cavity

\

ref. orbit

electrons

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Elettra Photon Beamlines

10

• 24 beamlines open to Users

• 3 new beamlines in commissioning

• Physics of Matter, Biology, Chemistry, Medical Science, Technology Materials, Environment, etc…

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Wavelength, Photon Energy

11

vsmc ][

vHzf 2][

hJE ][

c = 2.998e8 m/s h = 6.626e-34 J s

Light speed in vacuum

Planck constant

• An e.m. wave can be described also as a bunch of massless particles, named “photons”.

• Photons travel at speed c in vacuum.

• The energy of an e.m. wave (monochromatic) is the photon energy times the number of photons.

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Radiation Properties

12

multi-color wide source

multi-color collimated

monochromatic wide source

monochromatic collimated

= coherent !

Transverse & Longitudinal Coherence Brilliance

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Radiation Sources

13

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Spectral Flux

14

Ideal e-Beam Real e-Beam

Undulator resonance wavelength:

e-beam energy e-beam divergence

undulator period magnetic field

“undulator parameter”, it is proportional to the undulator magnetic field: K B

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New Generation is Coming

15

Upgrade of synchrotron light sources is planned worldwide, in order to reach a higher photon brilliance. More dipoles, smaller bending angle, smaller e-beam sizes, higher charge density.

From Elettra to Elettra 2.0:

Back Slides Follow

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Radiofrequency Electron Linac

17

400 m Accelerator Tunnel

200 m Undulator Hall

50 m Experimental Hall

Klystron Gallery

Machine Assembly Hall

Source: T. Inagaki, T. Shintake

8 GeV e-linac C-band (5.7 GHz) 35 MV/m acc. gradient 13000 cells mass production

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Radiofrequency Proton Linac

18

80–210 MeV p-linac C-band (5.7 GHz) <38 MV/m acc. gradient Rep.rate, 200 Hz

Source: A. Degiovanni, U. Amaldi

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Cyclotron (E.O.Lawrence & M.S.Livingstone, Berkeley 1931)

19

side view top view

Lorentz force

Classical approximation (e.g., massive particles)

Synchronism

Energy gain / turn

T

cm

cBq

T

T

T

22

1 2

0

• Spiraling motion:

• Maximum kinetic energy:

“Dees”

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Sinchro- and Sector- Cyclotron

20

RFc Cmq

B

mq

B

0

1 To maintain the synchronism, which ensures the multi/turn acceleration, one has two ways:

1. Increase B(t) synchronous to (t), (t)

2. Increase RF (t) synchronous to (t)

“sector cyclotron”

“sincro-cyclotron”

TRIUMPH, Canada CERN SC

N.B.: here the beam is bunched, over one period of modulation of RF !!