A brief history of

Particle Acceleratorsand Future

By Nawin Juntong

4 March 2014

A brief history of Particle Accelerators

A.W. Chao, W. Chou, Reviews of Accelerator Science and Technology Volume 1, World Scientific

Three separate roots1895 Philipp von Lenard, Electron scattering on

gases (Nobel prize 1905 for his work on

cathode rays). < 100 keV electrons

1906 Rutherford bombards mica sheet with natural

alphas and develops the theory of atomic

scattering. Natural alpha particles of several

MeV

1911 Rutherford publishes theory of atomic

structure

1913 Franck and Hertz excited electron shells by

electron bombardment (proved Niels Bohr's

theory, Nobel prize 1925 for their discovery of

the laws governing the impact of an electron

upon an atom). Wimshurst-type machines

1919 Rutherford induces a nuclear reaction with

natural alphas

…..Rutherford believes he needs a source of many MeV

to continue research on the nucleus. This is far beyond

the electrostatic machines then existing, but….

1928 Gamov predicts tunneling and perhaps 500

keV would suffice….

1928 Cockcroft and Walton start designing an 800

kV generator encouraged by Rutherford

1932 Generator reaches 700 kV and Cockcroft and

Walton split lithium atom with only 400 keV

protons. They received the Nobel prize in

1951 for their pioneer work on the

transmutation of atomic nuclei by artificially

accelerated atomic particles

1924 Ising proposes time-varying fields across

drift tubes. This is “resonant acceleration”,

which can achieve energies above the given

highest voltage in the system.

1928 Wideroe demonstrates Ising’s principle with

1 MHz, 25 kV oscillator to make 50 keV

potassium ions.

1929 Lawrence, inspired by Wideroe and Ising,

conceives the cyclotron.

1931 Livingston demonstrates the cyclotron by

accelerating hydrogen ions to 80 keV.

1932 Lawrence’s cyclotron produces 1.25 MeV

protons and he also splits the atom just a

few weeks after Cockcroft and Walton

(Lawrence received the Nobel prize in 1939

for the invention and development of the

cyclotron and for results obtained with it,

especially with regard to artificial

radioactive elements)

1923 Wideroe, a young Norwegian student, draws

in his laboratory notebook the design of the

betatron with the well-known 2-to-1 rule. Two

year later he adds the condition for radial

stability but does not publish.

1927 Later in Aachen, Wideroe make a model

betatron, but it does not work. Discouraged

he changes course and builds the linear

acceleration mentioned in Table 2.

1940 Kerst re-invents the betatron and builds the

first working machine for 2.2 MeV electrons.

1950 Kerst builds the world’s largest betatron of

300 MeV.

Resonant acceleration

Betatron mechanism

DC acceleration

P.J. Bryant, A brief history and review of accelerator, CERN

1919 - The birth of an era

Ernest Rutherford discovers the nuclear disintegration by

bombarding nitrogen with alpha particles from natural

radioactive substances. Later he calls for “ a copious

supply” of particles more energetic than those from

natural sources. The particle accelerator era is born.

Rutherford's transmutation apparatus

Hunterian Museum & Art Gallery collections, catalogue number GLAHM 113583

In this equipment, nitrogen atoms

were converted into oxygen

atoms, when in collision with

alpha particles from a source in

inside the horizontal enclosed

tube. Protons ejected by nitrogen

when forming oxygen were

detected at the rectangular

window at the end of the tube

Rutherford’s statement in address to the

Royal Society (1927)

A few years later in 1927 Rutherford, in his presidential address to the Royal Society, made a strong request for higher energy nuclear probes.

“ It has long been my ambition to have available for study a copious supply of atoms and electrons which have an individual energy far transcending that of the α and β particles from radioactive bodies. I am hopeful that I may yet have my wish fulfilled.”

Rutherford’s statement became a challenge to invent higher energy particle accelerators

A race for higher energy particle accelerators involved an early competition between electrostatic machines, but electric breakdown was a fundamental limitation to high voltages.

Meanwhile, it had already been realized by a few that another solution that avoided very high voltages was to use time-dependent accelerating fields.

1924 - Gustav Ising published an linear

accelerator concept

Gustav Ising (1924) published an

accelerator concept with voltage waves

propagating from a spark discharge to an

array of drift tubes

Voltage pulses arriving sequentially at the

drift tubes produce accelerating fields in

the sequence of gaps.

But Ising was unable to demonstrate the

concept.

1928 - World’s first accelerator1927 - Rolf Wideroe, Norwegian graduate student at Aachen

University discovered Ising’s 1924 publication in the university

library

1928 - Four year after Ising’s concept, Rolf Wideroe builds the

world’s first linac in an 88-cm long glass tube in Aachen, Germany.

Wideroe simplified Ising’s concept by replacing the spark gap with

an ac oscillator

For his PhD thesis Wideroe built and demonstrated a simple

linac, which had one drift tube between two accelerating gaps

1928 - World’s first acceleratorWideroe applied a 25-KV, 1 MHz AC voltage to the drift tube

between two grounded electrodes. The beam experienced an

accelerating voltage in both gaps.

He accelerated Na and K beams to 50 keV kinetic energy

equal to twice the applied voltage.

This is not possible using electrostatic voltages

“My little machine was a primitive precursor of this type of

accelerator which today is called a ‘linac’ for short. However,

I must now emphasize one important detail. The drift tube

was the first accelerating system which had earthed

potential on both sides, i.e. at both the particles’ entry and

exit, and was still able to accelerate the particles exactly as

if a strong electric field was present.“– Rolf Wideroe(From “The Infancy of Particle Accelerators, Life and Work of Rolf Wideroe” ed. Pedro Waloschek )

Robert Van de Graaff invents the Van de Graaff generator at

Princeton University. He also constructs the first tandem

accelerator (two generators in series) in 1959 at Chalk River.

1931, the large Van de Graaff generator was constructed

1929 –1932 - Van de Graaff generator

1930 - Cyclotron

Inspired by Rolf Wideroe's linac in a vacuum tube, Ernest

Lawrence invents the cyclotron at the University of

California, Berkeley. He and his student Stanley

Livingston build a cyclotron only 4 inches in diameter.

1932 - Lawrence’s cyclotron produces 1.25 MeV protons

and he also splits the atom just a few weeks after

Cockcroft and Walton

1932- Cockcroft-Walton acceleratorJohn Cockcroft and Ernest Walton invent the Cockcroft-Walton

electrostatic accelerator at the Cavendish Laboratory. This

accelerator produces the first man-made nuclear reaction.

Cockcroft, Rutherford, and Walton in 1932, shortly after they

accelerated protons against a lithium target, splitting the

lithium nucleus into two alpha particles, i.e., helium nuclei.

This demonstrated not only the “transmutation” of elements,

but also Einstein's formula E=mc2, since a slight loss of mass

produced energetic alpha particles

1937 - KlystronRussell and Sigurd Varian and William Hasen invent the kystron, a high-

frequency amplifier for generating microwaves, at Stanford University.

A similar device is proposed by Agnesa Arsenjewa-Heil and Oskar Heil

in 1935.

In 1948 they founded Varian Associates (along with Hansen and

Ginzton) to market the klystron and other inventions

Varian, Inc

Varian Semiconductor Equipment Associates Varian Medical Systems

acquired by Agilent TechnologiesSold the Electron Device

Business and formed

Communications & Power

Industries, Inc (CPI)

1940 - BetatronDonald Kerst at the University of Illinois constructs the first betatron,

proposed by Joseph Slepian and others in the 1920s.

1950 - Kerst builds the world’s largest betatron of 300 MeV.

1st – 2.3 MeV

2nd – 25 MeV300 MeV

1943 – Synchrotron

1944 – Phase stability

1943- Marcus Oliphant develops the concept for a new type of

accelerator, later named the synchrotron by Edwin McMillan.

1944- Vladimir Veksler at the Lebedev Institute of Physics and later

Edwin McMillan at the University of California, Berkeley, independently

discover the principle of phase stability, a cornerstone of modern

accelerators. The principle is first demonstrated on a modified

cyclotron in 1946 at Berkeley.

Technical difficulty

Ising and Wideroe established principle of resonance acceleration

Particles can gain arbitrarily high kinetic energy from successive traversals through the same accelerating fields with moderate voltages.

Particles acquire a small energy increment with each traversal

No basic limit to maximum kinetic energy.

Method can be applied to linear accelerators (linac) or to circular accelerators (cyclotron or synchrotron).

But with low (1-MHz) frequencies available at that time, linacs for faster protons and electrons had impractically large gap-to-gap spacings.

The gap-to-gap spacing is v/2f so high-velocity particles require high oscillator frequency to obtain satisfactory energy gain per gap.

At least a few hundred MHz were wanted, but RF frequencies available then were no more than 10 MHz.

Higher frequency microwave sources were unavailable until after WWII, a benefit of radar developments for the war.

The first proton and electron linacs were built after WWII

1939 – 1945 - World War II

1946 – Electron linacWilliam Walkinshaw and his team at Malvern in the U.K. build the first traveling

wave electron linac powered by a magnetron.

William Webster Hansen and his team independently build a similar electron

linac at Stanford University a few months later based on klystron and GeV

energy.

1946 – Synchrotron radiationFrank Goward constructs the first electron synchrotron in the

U.K. This is followed by one built by General Electric in the

U.S. where synchrotron radiation is first observed, open a new

era of accelerator-based light sources.

Langmuir is credited as recognizing it as synchrotron radiation or, as

he called it, "Schwinger radiation." Subsequent measurements by the

GE group began the experimental establishment of its spectral and

polarization properties. Characterization measurements were also

carried out in the 1950s at a 250-MeV synchrotron at the Lebedev

Institute in Moscow

The radiation is seen as a small

spot of brilliant white light by

an observer looking into the

vacuum tube

350 MeV @ University of Glasgow

1947 – Drift tube linacLuis Alvarez builds the first drift tube linac for accelerating

protons at the University of California, Berkeley.

L. Alvarez and coworkers at the Lawrence Berkeley Radiation

Laboratory developed a proton linear accelerator based on

injection of 200 MHz RF wave into a resonant metallic

cylindrical cavity containing the wideroe-type drift tube

arrangement.

- the linac is injected with a 4 MeV electrostatic accelerator

- protons are accelerated up to 32 MeV in the Alvarez structure

DTLs are nowadays currently used as primary

injection stages in hadron linac chains, or as

injectors into synchrotrons

1952 – Strong focusingErnest Courant, Stanley Livingston and Hartland Snyder at Brookhaven National

Laboratory and, independently Nicholas Christofilos earlier in 1950 in Greece discover

the principle of strong focusing.

Strong focusing and phase stability form the foundation of all modern high-energy

accelerator.

Weak focusing

1956 - FFAGThe first Fixed-Field Alternating Gradient (FFAG) accelerator is commissioned at

the Midwestern University Research Association. The concept is invented

independently by Tihiro Ohkawa, Andrei Kolomensky and Keith Symon. An earlier

variation is conceived by Llewellyn Thomas in 1938.

Kyoto University Research Reactor

Institute (KURRI),

Osaka, Japan

1959 – Modern SynchrotronThe first two proton synchrotrons using strong focusing – PS at CERN and

AGS at BNL – are built. An electron synchrotron using strong focusing is

built earlier in 1954 at Cornell University.

1955 - Milton Livingston builds a Synchrotron

capable of accelerating protons to 6.2 GeV

called the Bevatron.

1956 - Donald Kerst investigates the collision of

particle beams at relativistic energies.

1957 - Scientists at Dubna USSR build a

Synchrotron capable of accelerating protons to

10GeV called the Synchrophasotron.

1959 - Scientists at CERN, Geneva, using

Alternating - Gradient focusing build a

Synchrotron capable of accelerating protons to

28 GeV called the Proton Synchrotron (PS).

1960 - Scientists at Brookhaven build a

Synchrotron capable of accelerating protons to

33GeV called the Alternating - Gradient

Synchrotron (AGS).

Bevatron

Synchrophasotron

CERN - PS

John Adams with vodka bottle

1961 - Collider

1961 - The Austrian

physicist, Bruno Touschek

builds the first storage ring,

an electron - positron

storage ring, in Italy called

Aneii di Accumulazione

(AdA), but is too small to

be of experimental use.

AdA, the first electron-positron collider, is built at

Frascati, Italy. It is followed by two electron-

electron colliders: Priceton –Stanford Collider in

the U.S. and VEP-1 in Russia, leading to a

continuing evolution of electron-positron colliders

and factories around the world.

1964 – Induction linacAstron, the first induction linac proposed ny

Nicholas Christofilos for nuclear fusion, is built at

a branch of the Lawrence Radiation Laboratory,

later renamed the Lawrence Livermore National

Laboratory.

the main advantage of induction linacs is their ability to accelerate

long-pulse (tens of ns to µs) high-intensity (multi-kA) beams. Another specific feature is the

total electrical insulation of the apparatus, the high voltage appearing only inside the induction

cells.

1966 – 1968 – Beam cooling1966 – Gersh Budker invents electron beam cooling at

the Institute for Nuclear Physics in Russia.

1968 - Simon van der Meer invents stochastic beam

cooling, a technique enabling cooling of antiproton

beams. The proton-antiproton collisions in the SppS in

1981 at CERN lead to the discovery of the Z and W

bosons.

1968 - The Dutch physicist Simon van der Meer proposes

stochastic cooling. Researchers at SLAC carry out deep

inelastic scattering experiments of protons and neutrons

and discover the up, down and strange quarks.

electron cooling is used to shrink the size of electron beams

without removing any particles from the beam, increasing

luminosity in hadron colliders.

1969 - ISRIntersecting Storage Ring, the first large proton-proton collider begins at

CERN.

Scientists at CERN build the Intersecting Storage Ring (ISR) on the CPS

where 26 GeV proton beams are collided.

ISR at CERN. (a) Layout of proton synchrotron and two intersecting storage rings: (PS) proton synchrotron, (SR)

storage ring, (1)–(8) points of intersection of storage rings, (C1) and (C2) channels through which protons (p) are fed

into the storage rings. Preliminary acceleration of the protons is carried out in the booster; In the storage rings the

protons are additionally accelerated to 31.4 GeV. The arrows indicate the direction of motion of the protons. The

proton beams collide in the intersection zones of the storage rings. (b) Detail of intersection of proton beams

between sections A and A′: (1) structural elements of magnet focusing the proton beams.

1970 -RFQVladimir Teplyakov and Ilya Kapchinskii invent the radio frequency

quadrupole linacs. The first RFQ is built in 1972 at the Institute of

High Energy Physics in Russia.

1971 - FELJohn Madey invents and builds the first free electron laser at

Stanford University

1983 – Superconducting magnet

technology

The Tevatron, the first large accelerator

using superconducting magnet technology,

is commissioned at Fermilab.

1989 – Linear colliderSLC, the first linear collider proposed by Burton Ritcher, is built at

SLAC. The linear collider concept is developed by Maury Tigner in

1965.

1993 –Rise and fall of SSCConstruction of the Superconducting Super Collider, planned to be the largest

accelerator in the world, begin in 1989. The project is canceled by the U.S.

Congress in 1993.

The United States had planned the SSC on its own but asked other countries to get

involved when the cost began to expand beyond initial expectations.

Understandably, other countries were reluctant to fund a project in which they felt

no sense of ownership, not having served as designer or host. Congress pulled

funding for the SSC in 1993.

The Department of Energy pulled together a panel to discuss the future. In the

end, they decided to throw their weight behind the LHC.

If Congress had not cancelled the US-built

Superconducting Super Collider project in 1993, this

tunnel in Waxahatchie, Texas, would have held the

collider and its superconducting magnets, such as the

one shown below at Fermilab. A failure to secure

international partners to design and build the project

is among the reasons for the SSC's demise.

The global physics community has kept the lessons of the SSC and the LHC in mind

while planning for the next international accelerator project. This time, countries

are working together from the beginning. Physicists have already demonstrated this

attitude in developing three proposed accelerators: the International Linear

Collider, the Compact Linear Collider and a muon collider. At a relatively modest

scale, Fermilab has embarked on this path with its proposed new accelerator,

Project X.

Desertron 40 TeV, 87 km

1994 – Superconducting RF technologyCEBAF, the first large accelerator using superconducting radio frequency

technology, is built at the facility later named Jefferson Laboratory.

2005 – X-ray FELFLASH, the first VUV and soft x-ray free electron

laser user facility is built at DESY in Germany.

2008 - LHCThe Large Hadron Collider at CERN,

with 27 km circumference, begins

operation.

Future – Advanced conceptsPlasma and laser acceleration tantalizes one’s imagination. An acceleration gradient

1000 times higher than that of conventional means has been demonstrated. These

advanced concepts challenge future accelerator builders.

Leemans/Esarey(2009):Laser-driven plasma-wave electron accelerators.physicstoday

http://newscenter.lbl.gov/news-

releases/2011/03/17/simulating-at-lightspeed/

There are many more to come

Thank you

References A.W. Chao, W. Chou, Reviews of Accelerator Science and Technology Volume 1, World Scientific

P.J. Bryant, A brief history and review of accelerator, CERN

E. J. N. Wilson, FIFTY YEARS OF SYNCHROTRONS, CERN

Matt Luffoni, The history and revolution of Synchrotron radiation sources 1947-2007.

Thomas Wangler, Linear Accelerators Principles, History, and Applications.

John P. Wefel, Cosmic Rays and High Energy Physics.

Ron Ruth, Man-Made Accelerators (Earth-Based), SLAC.

Sergei Nagaitsev, Electron Cooling, Physics 598ACC lectures, 2007 Summer Term, Fermi.

Eugene S. Evans, Brief Overview of Wakefield Acceleration, University of California, Berkeley.

F. M´eot, An introduction to particle accelerators.

Shinji Machida, Fixed Field Alternating Gradient (FFAG) Accelerator

J. de Mascureau, INDUCTION LINACS

Leemans/Esarey(2009):Laser-driven plasma-wave electron accelerators.physicstoday

Alessandra Lombardi, Radio Frequency Quadrupole

Peter Schm¨user, Free Electron Lasers

http://www.accelerators-for-society.org/about-accelerators/timeliner/timeline.php#