Introduction to Accelerators III – Applications – E. Wilson

E.J.N.Wilson - Introduction to Accelerators III – Applications Slide 1Fig.

Low energy irradiation of materialDose and beam powerSynchrotron light sources (ESRF)The cone of synchrotron radiationThe spectrumThe scale of thingsDiffractionLithography Brightness Spallation source GSI – Ions Galore!HYOGO (JPN)- Ion beam medical centerEnergy amplifierInertial confinementThe development of acceleratorsNeed for higher energyCenter of mass v. Fixed targetLuminosityCLIC

Accelerators world-wide

E.J.N.Wilson - Introduction to Accelerators III – Applications Slide 2Fig.

Dynamitron

E.J.N.Wilson - Introduction to Accelerators III – Applications Slide 3Fig.

Dynam2.pct

Low energy irradiation of material

E.J.N.Wilson - Introduction to Accelerators III – Applications Slide 4Fig.

Electrons are easy to produce, accelerate and shieldUse an energy below the nuclear reaction threshold of 10 MeV. (7 MeV in some cases)

( )MeV 3 Efor g.cm 5.2

g.cm dxdE

1.5E thicknessmaximum

g.MeV.cm 8.1dxdEpower stopping

2

2

1-2

=≈

=

≈=

−

−

Sharf 8.2.jpg

Production line for sterilization

E.J.N.Wilson - Introduction to Accelerators III – Applications Slide 5Fig.

AC9.8.95_08(Impela).pct

Dose and beam power

E.J.N.Wilson - Introduction to Accelerators III – Applications Slide 6Fig.

A milliamp of particles, each losing 2 MeV, passing through a 1 cm cube of material will for one second will deposit a total energy of

This corresponds to a (beam) power of 2 kW1 Gy is 1 Joule per kilo and if the density of the cube is 1 this will be a dose of

This is not much and we need several kGy to disinfect material say 100 kW for 20 secondsThe dose would be the same for a thin film but we can use a lower energy and reach a much higher dose – 250 kGy to polymerize film.

Joules10.210 210 363 =×−

Gy 210 210 33 =×−

Methods of analysis by scattering

E.J.N.Wilson - Introduction to Accelerators III – Applications Slide 7Fig.

Spectrum from PIXE analysis

E.J.N.Wilson - Introduction to Accelerators III – Applications Slide 8Fig.

PIXE.pct

Scanning a lorry for drugs

E.J.N.Wilson - Introduction to Accelerators III – Applications Slide 9Fig.

Synchrotron light sources (ESRF)

E.J.N.Wilson - Introduction to Accelerators III – Applications Slide 10Fig.

AC9.8.95_16(ESRF).pct

The cone of synchrotron radiation

E.J.N.Wilson - Introduction to Accelerators III – Applications Slide 11Fig.

When an electron is bent in a circle it radiates synchrotron “light” along a tangent in a narrow cone (opening angle = 1/γ)

The spectrum

E.J.N.Wilson - Introduction to Accelerators III – Applications Slide 12Fig.

Spectrum is broad and looks the same when normalized to

Every quantity is normalized to the frequency of a characteristic quantum which is proportional to

uc = hω c =

32

hcγ 3

ρ

cu

The scale of things

E.J.N.Wilson - Introduction to Accelerators III – Applications Slide 13Fig.

[MeV] 12.4/E m 10 angstrom 1

photon

10-

==

Energy[GeV]

Photon[keV]

λ[Α]

BESSY-I 0.8 0.64 19.4 UVHELIOS 0.7 1.5 8.5 UVSRS 2.0 3.2 3.9 Hard XESRF 6.0 20.7 0.60 Hard X

LEP 50.0 88.5 0.14 Hard X

UV

Hard X

]mGeV[r

E 2218E 133beam

photon−=

Diffraction

E.J.N.Wilson - Introduction to Accelerators III – Applications Slide 14Fig.

Diffraction experiment (synch.rad)

E.J.N.Wilson - Introduction to Accelerators III – Applications Slide 15Fig.

Diff-phot.pctDiff-diag.pct

A very complex molecule

E.J.N.Wilson - Introduction to Accelerators III – Applications Slide 16Fig.

RNA Polymerase – the structure that enables the code for each protein to be used to make each protein

Lithography in practice

E.J.N.Wilson - Introduction to Accelerators III – Applications Slide 17Fig.

AC9.8.95_11(mask).pct

Brightness (importance of small emittance)

E.J.N.Wilson - Introduction to Accelerators III – Applications Slide 18Fig.

γσσσθ

φθ

36.236.236.2

Brightness4

zx

ddFddxdzd

d

=

=

γσ

θ

γ 21

fluxintegratedy verticalltheis where

≈

ddF

Brightness is measured in :

Wigglers and undulators enhance this!

bandwidth 0.1%/mr/c/mmphotons/se 22

ISIS

E.J.N.Wilson - Introduction to Accelerators III – Applications Slide 19Fig.

Spallation source (ESS)

E.J.N.Wilson - Introduction to Accelerators III – Applications Slide 20Fig.

Compare with ISIS

Average Beam Power: 2 x 5 MW

Average Neutron Flux :3.1 x 1014 n/cm2s

Pulse frequency = 16 2/3 Hz

Neutron pulse length = 2 Milliseconds

Mean Power = 5 MW

Target material = mercury

Max. Neutron flux = 1 x 1016 n/cm2s

Proton energy: 0.800 GeV

Protons per second: 2.5 x 1013 x 50 Hz = 1.3x1015

Current = Charge/sec:x1.3x 1015 x 1.6 x 10-19

=0.2 mA

Mean Power = 0.2 mA x 800 MeV = 0.16 MW

High temperature superconductor

E.J.N.Wilson - Introduction to Accelerators III – Applications Slide 21Fig.

Crystal structure of the 90K YBa2Cu3O7 superconductor

HgBa2CuO4.Color-PICT

GSI – Ions galore!

E.J.N.Wilson - Introduction to Accelerators III – Applications Slide 22Fig.

View along the SIS accelerator ring, which can accelerate the ions comingfrom the UNILAC to 90% of the speed of light.

accel.gif

Ion- beam surface treatment

E.J.N.Wilson - Introduction to Accelerators III – Applications Slide 23Fig.

Setup for surface treatment of artificial knee joint by low energy ionimplantation. Collaboration Aesculap and Technical University Darmstadt

Kniegelenk.gif

Membranes made with ion-beams

E.J.N.Wilson - Introduction to Accelerators III – Applications Slide 24Fig.

The damage produced by the heavy ions along the track in the material canbe used to develop pores. With this technique tracks in many polymers, crystalline insulators, glasses, semi-conductors and recently amorphous metals are etcheable.

Etched ion tracks in polymer foil. The pore density is 10 millionper cm^2. By ion track etching it is possible to produce membraneswith track diameter from 10 nm up to 10 µm and densities from 1 to10^9 pores per cm^2.

quartz_MITE.gif

Quartz micro machining by control of ion track etch access

E.J.N.Wilson - Introduction to Accelerators III – Applications Slide 25Fig.

fluence= ions per area [ions / cm2]1 ion/sample-single pore membrane106…1010 ions/cm2-etching109…1011ions/cm2 -single track regime1011 1014ions/cm2 -overlapping tracks

quartz_MITE.gif

HYOGO (JPN)- Ion beam medical center

E.J.N.Wilson - Introduction to Accelerators III – Applications Slide 26Fig.

Particle species p, He and C

Beam energy for p and He [MeV/u]

Beam energy for C [MeV/u]

Beam spill length [ms]

Repetition rate for He and C [Hz] 0.5

70 - 230

70 - 320

400

Beam intensity is typically 1010 pppThe tumor is “painted “ with beamDepth modulation = energy loss absorberSlow extraction must be ripple free.

Depth in tissue

E.J.N.Wilson - Introduction to Accelerators III – Applications Slide 27Fig.

Lawrence’s Cyclotron

E.J.N.Wilson - Introduction to Accelerators III – Applications Slide 28Fig.

Isotopes for PET

E.J.N.Wilson - Introduction to Accelerators III – Applications Slide 29Fig.

petiso.pct

Energy amplifier

E.J.N.Wilson - Introduction to Accelerators III – Applications Slide 30Fig.

Carlo.pct

Inertial confinement

E.J.N.Wilson - Introduction to Accelerators III – Applications Slide 31Fig.

The history of accelerators

E.J.N.Wilson - Introduction to Accelerators III – Applications Slide 32Fig.

Need for Accelerators

E.J.N.Wilson - Introduction to Accelerators III – Applications Slide 33Fig.

Why do we need accelerators? (2)

Resolution of "Matter" Microscopes:

Wavelength of Particles (Photon, Electron, Proton, ...): (de Broglie, 1923)

λ = h / p ( = 1.2 fm / p [ GeV/c] ) The higher the momentum, the shorter the wavelength, the better the resolution

Energy to Matter: Einstein (1905):

Higher energy means we can produce more massive particles

When particles approach the speed of light, they get more massive, but not faster

33

E = mc 2 = mo c 2

1−v 2

c 2

= γ moc 2

Center of mass v. Fixed target

E.J.N.Wilson - Introduction to Accelerators III – Applications Slide 34Fig.

W = Energy available in center-of-mass for making new particles For fixed target :

Ec.m. ≅ 2mTEB... and we rapidly run out of money trying to gain a factor 10 in c.m. energy

But a storage ring , colliding two beams, gives:

Ec .m. ≅ 2 EB

Problem: Smaller probability that accelerated particles collide .... "Luminosity" of a collider

L = N1N21A

βc2πR

≈ 1029 ...1034 cm −2s −1

Luminosity

E.J.N.Wilson - Introduction to Accelerators III – Applications Slide 35Fig.

Imagine a blue particle colliding with a beam of cross section area - AProbability of collision is

For N particles in both beams

Suppose they meet f times per second at the revolution frequency

Event rate

σA

⋅ N

σA

⋅ N2

f rev =βc

2πR

f rev N 2

A⋅ σ

LUMINOSITY

Make small

Make big

≈ 1030 to 1034 cm-2 s-1[ ]

e.g. 10−25

CLIC SCHEME

E.J.N.Wilson - Introduction to Accelerators III – Applications Slide 36Fig.

Summary of lecture: III – Applications – E. Wilson

E.J.N.Wilson - Introduction to Accelerators III – Applications Slide 37Fig.

Low energy irradiation of materialDose and beam powerSynchrotron light sources (ESRF)The cone of synchrotron radiationThe spectrumThe scale of thingsDiffractionLithography Brightness Spallation source GSI – Ions Galore!HYOGO (JPN)- Ion beam medical centerEnergy amplifierInertial confinementThe development of acceleratorsNeed for higher energyCenter of mass v. Fixed targetLuminosityCLIC