Transcript Particle Accelerators - Electrical and Computer Engineering

Particle Accelerators and
Detectors
World’s Largest ‘Microscopes’
Contents
What is a Particle Accelerator?
An Early Accelerator
Modern Linear and Circular Accelerators
Particle Detectors
Examples of Accelerators and Detectors
Accelerators and Detectors as Giant
Microscopes
What is a Particle Accelerator?
Any device that
accelerates charged
particles to very
high speeds using
electric and/or
magnetic fields
The picture to the right shows an early
particle accelerator from 1937. This
accelerator was used in the
development of the first atomic bomb.
http://en.wikipedia.org/wiki/Image:P3280014.JPG
An Early Accelerator
In 1929, Ernest Lawrence developed the first
circular accelerator
This cyclotron was only 4 inches in diameter,
and contained two D-shaped magnets
separated by a small gap
An oscillating voltage created an electric field
across the small gap, which accelerated the
particles as they went around the accelerator
An Early Accelerator, cont.
Here is picture of Lawrence’s cyclotron:
http://www.facstaff.bucknell.edu/mvigeant/univ_270_03/Jaime/History.html
Today’s Accelerators
Modern accelerators fall into two basic
categories:


Linear Accelerators
Circular Accelerators
Linear Accelerators
In linear accelerators, particles are accelerated in a
straight line, often with a target at one to create a
collision
The size of linear accelerators varies greatly


A cathode ray tube is small enough to fit inside of a
television
Stanford’s linear accelerator is two miles long
http://www.exploratorium.edu/origins/cern/tools/linac.html
Linear Accelerator – Example 1
(Cathode Ray Tube)
The cathode ray tube is a linear accelerator
found in many TVs, computer monitors, etc.
http://science.howstuffworks.com/atom-smasher2.htm
Linear Accelerator - Example 2
(Stanford Linear Accelerator)
http://en.wikipedia.org/wiki/Image:LINAC.jpg
Circular Accelerators
www.fnal.gov
Circular accelerators
propel particles along a
circular path using
electromagnets until the
particles reach desired
speeds/energies
Particles are accelerated
in one direction around
the accelerator, while
anti-particles are
accelerated in the
opposite direction
Circular Accelerators, cont.
Circular accelerators are able to bring
particles up to very high speeds (energies) by
allowing each particle to be accelerated for a
longer period of time—around the
accelerator.
The distance around a circular accelerator can
be quite large


Fermilab’s Tevatron (Near Chicago, USA) - 4 miles (6.44 km)
CERN’s LHC (Near Geneva, Switzerland) – 16.8 miles (27 km)
Fermilab Accelerators
The protons and anti-protons at Fermilab go through
a series of accelerators in order to accelerate them to
1 TeV (just 200 miles per hour slower than the speed
of light)
At Fermilab, protons are accelerated in one direction
around the ring; anti-protons are accelerated in the
opposite direction
The series of accelerators at Fermilab is illustrated by
an animation located at this website (be sure to press
“play”):
http://www-bd.fnal.gov/public/index.html
Collisions
The particle and anti-particle beams are
focused and directed at particular sites
around the ring in order to collide with one
another
These collisions are designed to occur within
detectors, which are able to analyze the
many events (particles created, etc.) that
result from the collisions of the particles and
anti-particles
Particle Detectors
The large detectors are
able to trace and
characterize the
particles that result
from the collisions
The picture to the right
shows the 5,000-ton
CDF Collider Detector at
Fermilab
400,000 protonantiproton collisions
occur each second in
this detector
http://www.fnal.gov/pub/about/tour/index.html
Particle Detectors, cont.
By analyzing the
nature and type of
particles resulting
from the collisions,
scientists are able to
learn much about
matter at a more
fundamental level
http://www.fnal.gov/pub/now/live_events/index.html
CERN Accelerators and
Detectors
The diagram to the
right shows the
accelerators and
detectors at CERN near
Geneva, Switzerland
The LHC is the largest
circular accelerator at
CERN and is to begin
operation in 2007
CMS and ATLAS are two
of the five examples of
detectors approved at
CERN for the LHC
Fermilab Accelerators and
Detectors
The most powerful
accelerator (the
Tevatron) in the US is at
Fermilab
The diagram to the
right shows the series
of accelerators
(including the Main
Injector and Tevatron)
and detectors (including
CDF and DZERO) at
Fermilab
http://www.fnal.gov/pub/about/whatis/picturebook/descriptions/00_635.html
Accelerators and Detectors as
Giant Microscopes
Together, particle
accelerators and detectors
have helped scientists
discover very small building
blocks of matter
For instance, scientists now
think that protons within
atoms are made up of even
smaller particles known as
quarks
Check out
www.particleadventure.org
for more information
http://www2.slac.stanford.edu/vvc/theory/fundamental.html