Particle accelerators allow physicists to observe fundamental particles by speeding particles up to high energies and smashing them together. The document describes various components of particle accelerators including injection systems, vacuum chambers, radio-frequency cavities, and focusing and bending magnets. It provides examples of different types of accelerators like linear accelerators and circular accelerators/synchrotrons. Specific accelerator facilities at SLAC and Fermilab are outlined, detailing the series of accelerators used like electron guns, damping rings, and various circular accelerators that work together to boost particle energies for experiments.

1. Particle Accelerators
Nguyen Hong Quang
Materials Science and Metallurgy Department
Student Number: 2003437007
Email: quang_nh2002@yahoo.com
Oct 18th 2004

2. Outlines
• How physicists observe and study
fundamental particles
• What is a particle accelerator
• Principle machine components of accelerators
• Types of accelerators
• References

3. How physicists observe and study
fundamental particles
- Particle accelerators: Speed up particles to very high
energies before smashing them into other particles.
- Particle detectors: allow physicists to observe and
study the collisions.
By accelerating and smashing particles, physicists can identify
their components or create new particles, revealing the nature
of the interactions between them.
Since fundamental particles are extremely tiny, in order to see
and study them physicists need very special tools:

4. What is a particle accelerator?
Accelerators can be used to
transform energy into mass and
vice versa.
An accelerator can be used as a
super-microscope to "see" tiny
particles (quarks, leptons, etc)
http://nobelprize.org/physics/educational/accelerators/research-1.html

5. Accelerator as super-microscope
 Tiny particles (smaller than a micron)
can be examined by using electrons,
provided their energy large enough.
This is the principle of the electron
microscope (SEM, TEM, HRTEM…)
 The electron microscope is actually a
small accelerator. It conveys energy to
charged particles (electrons) to make
wavelength small enough to view such
details.
 The smaller the details you want to
see, the larger the accelerator you will
have to build.
The larger the energy
the smaller is the wavelength.
http://nobelprize.org/physics/educational/accelerators/research-3.html

6. Accelerator as energy transformer
 In accelerators, charged
particles are accelerated to
high energy (high speed) by
electric fields.
 In particle collisions, more or all
the available energy can be
transformed into other
particles or into X-rays:
 The more powerful accelerators
and higher energies, the more
massive and sometimes new
particles can be discovered
E = mc2
Energy  Mass
http://nobelprize.org/physics/educational/accelerators/research-2.html

7. Principle machine components
of an accelerator
- Injection: Let original particle
come to the vacuum chamber
-Vacuum chamber: Avoid the
accelerated particles collide with
normal matter (like air molecules)
- Radio-Frequency Cavities:
Provide electric fields to speed up
charged particles
- Bending Magnets (dipole
magnets): Curve the particles in
the vacuum chamber
- Focusing Magnets(quadrupole
magnets) Concentrate the
particles into a thick beam.

8. Type of accelerators
Linear accelerator (LINAC)
Fixed Target
Colliders
Circular accelerator (synchrotron)
(Source: http://pdg.web.cern.ch/pdg/cpep/lin_circ.html)

9. Accelerator Components
• Electron Gun
• Damping Rings
• Beam Switch Yard
• Klystrons
A LINAC: SLAC’S ACCELERATOR CHAIN
(SLAC = Stanford Linear
Accelerator Center)

10. SLAC: Electron Gun
http://www2.slac.stanford.edu/vvc/accelerator.html

11. SLAC: Beam Switch Yard
http://www2.slac.stanford.edu/vvc/accelerator.html

12. SLAC: Damping Ring
http://www2.slac.stanford.edu/vvc/accelerator.html

13. • The electron gun produces a flow of
electrons
• The bunching cavities regulate the speed of
the electrons so that they arrive in bunches at
the output cavity.
• The bunches of electrons excite microwaves
in the output cavity of the klystron.
• The microwaves flow into the waveguide ,
which transports them to the accelerator .
• The electrons are absorbed in the beam stop.
SLAC: Klystron
http://www2.slac.stanford.edu/vvc/accelerator.html

14. A synchrotron: Fermilab’s accelerators
Source: http://www.fnal.gov

15. FERMILAB’S ACCELERATOR CHAIN

16. FNAL: Cockroft-Walton accelerator
- Developed by John D. Cockroft
and Earnest T. S. Walton at the
Cavendish Laboratory (England)
- This type of accelerator consists
of a multi-step voltage divider
which accelerates ions linearly
through constant voltage steps
-The major accelerator facilities
make use of several types of
devices to build up the energy of
the particles.
- The Cockroft-Walton
accelerator is used as the first
stage of acceleration at Fermilab
http://www.fnal.gov

17. FNAL: The LINAC at FermiLab
The Fermilab Linac is a
negative hydrogen ion, 400
MeV accelerator. It includes a
25 keV H-minus ion source, a
750 keV electrostatic
accelerating column, a 116 MeV
drift-tube (Alverez) linac
operating at 201.25 MHz, and a
401 MeV side-coupled cavity
linac operating at 805 MHz

18. FNAL: The booster
The Booster is a circular accelerator (synchrotron) that uses magnets
to bend the beam of protons in a circular path. The protons travel
around the Booster about 20,000 times so that they repeatedly
experience electric fields. With each revolution the protons pick up
more energy, leaving the Booster with 8 billion electron volts (8 GeV).
http://www-visualmedia.fnal.gov/VMS_Site/active.html

19. FNAL: The Main Injector Tunnel
- Main Injector, completed in
1999, accelerates particles
and transfers beams.
- The functions of Main
Injector Tunnel:
1) Accelerates protons from 8
GeV to 150 GeV.
2) Produces 120 GeV protons,
which are used for antiproton
production.
3) Receives antiprotons from
the Antiproton Source and
increases their energy to 150
GeV.
4) Injects protons and
antiprotons into the Tevatron.
http://www-visualmedia.fnal.gov/VMS_Site/active.html

20. FNAL: The Tevatron
-The Tevatron receives 150 GeV
protons and antiprotons from the
Main Injector and accelerates
them to almost 1000 GeV, or one
tera electron volt (1 TeV).
- Traveling only 200 miles per
hour slower than the speed of
light, the protons and antiprotons
circle the Tevatron in opposite
directions.
- The beams cross each other at
the centers of the 5000-ton CDF
and DZero detectors located
inside the Tevatron tunnel,
creating bursts of new particles
http://www-visualmedia.fnal.gov/VMS_Site/active.html

21. FNAL: The Tevatron Works

24. References
[1] Introduction to High Energy Physics, 4th Edition, Donald H. Perkin,
University of Oxford, 2000
[2] http://www.fnal.gov
[3] http:// www.cern.ch
[4] http://www.egglescliffe.org.uk/physics/particles/newfolder/acc1.html
[5] http://particleadventure.org/particleadventure/
[6] http://hands-on-cern.physto.se/
[7] http://hyperphysics.phy-astr.gsu.edu/hbase/particles/accel2.html
… and many different websites