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Accelerators

Ken PeachJohn Adams Institute for Accelerator Science

Charters School

28th February 2007

Ken Peach John Adams Institute 28 2 2007 2

Outline

• Accelerators– Early Accelerators– Accelerators today

• Science– Particle Physics and Cosmology– Other sciences

• Society– Medicine

• Summary & Conclusions


Accelerators


The 1st Accelerator Experiment?• Galileo Galilei (1564 - 1642)

• (Probably apocryphal)

– Use Leaning Tower of PisaLeaning Tower of Pisa • time to fall independent weight

– Result?

• The Law of Gravity!

1 22

12N

mGF

r

m

Galileo Aristotle


Lessons

1. Cost is significant

2. Limit to energy with the same technology

3. Higher energy needs a different approach

not more of the “old” method

Étienne & Joseph Montgolfier

Galileo Aristotle

1 22

12N

mGF

r

m


Cockcroft and Walton (UK)

Early accelerator

From the early days to

ISIS@RAL

The “Leaning” Cockcroft &

Walton


+ +-

The Linear Accelerator (Linac)

+ -+


The Linear Accelerator (Linac)

-+ -+ -+ -+- + - + - + - +Each voltage step is “modest”

Inside a Linac

The LEP Linear Injector Linac


SLAC – The Stanford Linear Accelerator (Centre)

50 GeV electrons and positrons

2.8GHz RF

17MeV/m


Lawrence (US) – the Cyclotron

The Chicago Cyclotron Magnet

Lawrence’s 1st cyclotron


The Cyclotron


Lawrence (US) – the Cyclotron

The Chicago Cyclotron Magnet

Lawrence’s 1st cyclotron


Mark Oliphant and the Birmingham Synchrotron

1940s, Mark Oliphant

• designed and built a 1 GeV proton synchrotron at Birmingham

• (almost) the first working proton synchrotron in the world!

(Just beaten by Berkeley)

Mark Oliphant

1901-2000

Oliphant also build a 400MeV cyclotron in Birmingham in the late 1930s


CERN in Geneva (& France)


LEP – the Large Electron-Positron Collider

The Largest (electron) Synchrotron [so far!]


Science


The equation of the Universe!

(after Feynman)

We know the equation of the Universe

U = 1U = 0 The trouble is, we have no idea what U is!!!!

but … we know a lot about what U contains


How to discover the structure of the Universe

• 3 basic waysLook at it Heat it Smash it

Wavelength Temperature T Energy E

hc/ = kT E=


Remarkable comment

All three the same fundamental physics!

Uses ‘light’ Uses ‘heat’ T Uses ‘probe’ E

hc/ = kT E=

Photons Photons ‘Photons’


The Big Bang

BIGBANG


LEP – the Large Electron-Positron Collider


ALEPHA detector for LEP Physics

©


Some events ‘evaporating from the vacuum’

Ze+e- Z+-

Z+ -Zqq


Some more (complicated) events

Z+- Zqqg

Z4 ‘jets’

ZW+W-


High Precision Frontier

Known phenomena studiedwith high precision may show

inconsistencies with theory

High Energy Frontier

New phenomena(new particles)

created when the “usable” energy > mc2 [×2]

Accelerators for particle physics

What is needed, and why

2 routes to new knowledge about the fundamental structure of the matter


HiggsHiggsBosonBosonHiggsHiggsBoson?Boson?

For

ceF

o rce

Car

riers

Car

r iers

ZZ boson

WW boson

photon

ggluon

Generations of Generations of matter matter

-neutrino

tau

bbottom

ttop

III III

-neutrino

muon

sstrange

ccharm

II II

ee-neutrino

eelectron

ddown

upu

I I

Lept

ons

Lept

ons

Qua

rks

Qua

rks

The experimentalist’s view

Each with its own

‘antiparticle’

© Brian Foster

Particles and

Forces


What remains to be done?

• The Standard Model is a very good description of the Universe at the particle scale (~2MW)– But does not explain many things

• Why so many particles?• Why so many forces?• What is mass?

– Why do particles have the masses they have?

• How do neutrinos get mass?– Are neutrinos different? How do they fit in?

• What is Dark Matter? Dark Energy?• Why is matter different from antimatter?

– (Where did all the antimatter go?)

• Where does gravity fit in?


The Large Hadron Collider @ CERN

• 7,000,000,000,000 volt protons colliding head on

• 40,000,000 times per second

protons protons

What Happens?


The Large Hadron Collider @ CERN


LHC machine status


The Large Hadron Collider

ATLAS

CMS


Status 16th February 2006


Status 23rd February 2007


What does the LHC hope to find?

1. The Higgs Boson– Complete the “Standard Model”– Confirm that we “understand” mass

• But perhaps not !

2. Find something new– Clues to “Beyond the Standard Model”

• Towards a “Standard Theory”• That Explains as well as Describes

– Supersymmetry• A new completely type of particle

Could explain Dark Matter

– Extra Dimensions• We lives in 1 time + 3 out of n space dimensions!

– The unexpected


The Unexpected

protons protons


After the LHC?

– What next?– Need to study the new discoveries

– Precision measurements

– History shows that– Proton colliders are good at discovery– e+e- colliders are good at precision

measurement

– Need higher energy than LEP– But synchrotrons at the limit

– Synchrotron radiation– E4 at fixed radius

– i.e. 2 Energy = 16 Power or 16 Radius!

– Back to the Linac!!!!


Why an e+e- collider?

After Barry Barish

LEP

LHC


A Linear Collider

~30 km!


The heart of the Linear Collider


Other Sciences


Accelerators for other sciences

Neutron sources

X-ray sources

Nuclear Physics

Accelerators for other applications

Accelerators in Medicine


NIMROD @ RAL & NINA @ Daresbury

• Built in the 1960s– NIMROD @ RAL

• 8 GeV proton synchrotron

– NINA @ Daresbury• 3 GeV electron synchrotron

• Both closed in the 1970s!– The UK’s accelerators were “@CERN”

• New projects from their ashes– ISIS @ RAL

• 800MeV proton synchrotron for a

Spallation Neutron Source

– SRS @ Daresbury• 2GeV Synchrotron Radiation Source

}

Particle Accelerators for other sciences

(Physics, Chemistry,

Engineering, Biology, Medicine)


What is a Spallation Neutron Source?

High Energy (~1GeV)High Power (~MW)

(ISIS – 0.16MW)

nn

n

n

n

n n

nTargetProtons


ISIS @ RALISIS @ RAL

ISIS:50 Hz800 MeV300 µA

ISIS @ RAL

600 Experiments/year1200 Users/year235 UK Groups


Neutron Scattering (ISIS)


What is Synchrotron Radiation?

Motion of a charged particle (an electron) in a magnetic field

When ultra-relativistic, emits x-rays tangential to the motion

X-ray


SRS @ Daresbury

Sir John Walker,

Nobel Prize in Chemistry, 1997

“for elucidation of the

enzymatic mechanism underlying

the synthesis of adenosine triphosphate

(ATP)”


Examples of use of Synchrotron Radiation

CCLRC/SRD annual report


Diamond & the ISIS 2nd Target Station


SocietyAccelerators in Medicine

Proton and Heavy Ion Therapy

(not discussed: Accelerator Driven Reactors

Accelerator Driven Transmutation of radioactive Waste)


Incidence of Cancer in the UK

• 13.5% probability, all types (except skin cancer)– Around half are associated with specific risks– Statistically, some will be close to sensitive tissue

• And difficult to treat surgically or chemically

Source: Cancer Research UK


The Clatterbridge Centre for Oncology


The Clatterbridge Centre for Oncology

• Established 1989 – First hospital based

proton therapy – >1400 patients with

ocular melanoma– First example of 3D

computer treatment planning in UK;

• eye gaze direction used to obtain best approach angle to eye.

• Unsung success story of British Oncology!

After Bleddyn Jones


The ‘spread-out’ Bragg Peak –plateau effect

[SOBP]

65MeV 140meV200MeV

5 10 cmDepth

Dose (%)

Effective Range varies with proton Energy

Why use protons?

After Bleddyn Jones


Single field100

50

2 opposed fields200

50

3 co-planar fields300

50

PROTONS X-Rays

2 opposed fields

3 co-planar fields

Single field

100

200

100

Depth Depth

% DOSE

%DOSE

How does it work?

After Bleddyn Jones


X-Rays

Protons 30050 50

60

100

80 80150

0

60

Axial view

3 Field techniques

After Bleddyn Jones


Many centres world-wide

based on information of the Particle Therapy Co-Operative Group (PTCOG)


Hadron Therapy in Chiba(Japan)

Stolen from Loma LindaBorrowed from Rob Edgecock


Medical applications of accelerators

• Oncology– Protons, heavy ions, electrons

• Why so little interest in the UK?

• Preparation of radio-nuclides

• Requires precision control of– Energy– Dose

• Just like the linear collider (energy, luminosity)


Summary and Conclusions

• Particle Accelerators are important tools– For Particle Physics (& cosmology)

• Science [and Society] will benefit– Science

• understanding the structure of (bio)materials

– Society• New and better materials• New and better drugs• New (and better?) therapies

• and they are fun too!

http:// [email protected] accelerators ken peach john adams institute for accelerator...

Documents

cyclotron slide

science slide

s slide

mevm slide

galileo aristotle slide

geneva france slide

leaning cockcroft walton

big bang big bang slide