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Studying and Applying Channeling at Extremely High Bunch Charges. Dick Carrigan Fermilab International Workshop on Relativistic Channeling and Related Coherent Phenomena March 23, 2004, Frascati, Italy. The dream of crystal channeling. ( Aarhus ).

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studying and applying channeling at extremely high bunch charges

Studying and Applying Channeling at Extremely High Bunch Charges

Dick Carrigan

Fermilab

International Workshop on Relativistic Channeling and Related Coherent Phenomena

March 23, 2004, Frascati, Italy

the dream of crystal channeling
The dream of crystal channeling
  • (Aarhus)

Relativistic Channeling - Frascati March 23, 2004

bob hofstadter the atomic accelerator hepl 560 1968
Bob Hofstadter "The Atomic Accelerator" HEPL 560 (1968)
  • "To anyone who has carried out experiments with a large modern accelerator there always comes a moment when he wishes that a powerful spatial compression of his equipment could take place. If only the very large and massive pieces could fit in a small room!”

Relativistic Channeling - Frascati March 23, 2004

hofstadter wanted a crystal accelerator
Hofstadter wanted a crystal accelerator!
  • A table top accelerator ("miniac")
    • The first solid state accelerator
    • use channeling for focus
    • maybe an after-burner scheme
    • excite atoms coherently with 1 keV-xray

Get out 1 keV/Å

  • in 1 cm would get 100 GeV

Need an x-ray laser (1968)

Problem-transit time

Relativistic Channeling - Frascati March 23, 2004

visionary possibilities for acceleration
Visionary possibilities for acceleration

Would like much higher accelerating gradients

Two thoughts:

  • Lasers
    • R. Palmer, Particle Accelerators V11, 81 (1980). Recent progress Kimura et al. PRL 92, 054801 (2004). See also LEAP at Stanford (Colby)

Plasmas

  • Tajima and Dawson PRL 43, 267 (1979)
  • E. Esarey, et al., IEEE Trans. On Plasma Sci, 24, 252 (1996).
  • J. Dawson, Scientific American March, 1989 (p. 54)

Relativistic Channeling - Frascati March 23, 2004

pseudo solid state accelerators

Livermore

wedge

+ -

+ -

+ -

Laser Debye Protons

sheath

Pseudo solid state accelerators
  • At least four groups see high energy ions, electrons from intense lasers hitting foils
    • Livermore PRL 85, 2945 (2000)
    • Michigan APL 78, 595 (2001)
    • Rutherford PRL 90, 064801 (2003) – discussion of mechanisms, target evolution
    • LULI PRL 85 1654 (2002)

3*1020 W/cm2, 1000 TW, 1013 proton beams with E to 58 MeV, electrons

protons can be focused by curving target

process: electrostatic fields produced by ponderomotively accelerated hot

electrons act on protons from absorbed hydrocarbons rear side (downstream)

Relativistic Channeling - Frascati March 23, 2004

plasma wake field acceleration
Plasma wake field acceleration

G= 0.96(n0)½ (V/cm) n0 is electron density

RF cavity 0.0005 GV/cm

gaseous plasma 1 GV/cm

solid state plasma 100 GV/cm

Photo S. Carrigan

Relativistic Channeling - Frascati March 23, 2004

a wakefield accelerator e157 at slac
A wakefield accelerator - E157 at SLAC

Head of beam generates plasma wakefield,

tail is accelerated by 80 MeV. Also do e+ - E162.

(E-164 later version , ne O(3*1015), 100 micron bunches

- see 2003 Particle Acc. Conf, p. 1530)

M. HoganPhys. Plasmas 7, 2241 (2000)

Relativistic Channeling - Frascati March 23, 2004

results from slac e 157
Results from SLAC E-157

Acceleration

Barov and Rosenzweig (UCLA) see similar results at Fermilab.

100 MeV/m using A0 14 MeV photoinjector. 6-8 nC, ne ~ 1014/cc.

M. HoganPhys. Plasmas 7, 2241 (2000)

Relativistic Channeling - Frascati March 23, 2004

basic crystal accelerator concept
Basic Crystal Accelerator Concept
  • excite plasma wake field in solid with density a thousand times gas
  • use channeling to reduce energy loss, focus, and maybe even cool

Chen-Noble Tahoe (1996), p. 441

  • Big problems!
    • blow away material
    • dechanneling

Positives

  • very high power, femtosec lasers
  • radiative damping (Huang, Ruth, Chen)

Relativistic Channeling - Frascati March 23, 2004

the fermilab a0 photoinjector
The Fermilab A0 photoinjector
  • built as Tesla injector prototype in the late 1990s by Helen Edwards’ group
  • essentially a gigantic phototube powered by a laser

followed by a so-called 3.5 MeV warm RF gun

and second stage of a Tesla superconducting nine-cell RF cavity

  • beam energy 14.4 MeV.
  • very large picosecond electron pulses of 10 nanocoulombs or 106 A/cm2
  • So what did the Fermilab A0 photoinjector do?
    • studied channeling nearer extreme conditions needed for

a channeling accelerator

    • Could we make a crystal accelerator or do

unique channeling studies?

Relativistic Channeling - Frascati March 23, 2004

crystal survivability

electronic plasma decay

via interband transitions

lifetime: (plasma frequency)-O(fs)

excitation of phonons in lattice

crystal disorder, fracture, or vaporization

lattice dissociation via

plasmon absorption

lifetime: (ion plasma frequency)-1

vaporization O(10-100 fs)

hydrodynamic heating O(1-10 ps) [Livermore]

Crystal survivability?

Process

  • excite electronic plasma
      • tunnel ionization
      • partial or total lattice ionization

Relativistic Channeling - Frascati March 23, 2004

dynamic channeling

Andersen96

Dynamic channeling
  • Intense beam through crystal could blow away electrons in much less than a picosecond
  • Acts like a larger screening length

Relativistic Channeling - Frascati March 23, 2004

crystal destruction
Crystal destruction
  • ACCELERATION
      • G (gradient) proportional to (n0)1/2, P (power) prop to n0
      • for G = 1 GeV/cm P = 105 J/cm3
      • 1019 W/cm3
      • for O(10 fs) @ 1 GeV/cm

LASER

1011 W/gm

Belotshitkii & Kumakhov (1979)

or 106 a/cm2 for particle beam

1012 W/cm3 ns long pulses

1013 W/cm3 Chen-Noble (1987)

fracture threshold

O(0.1 ns) ref 16

Skin depth < 0.1 mm

LATTICE IONIZED

1015-1016 W/cm2 Chen & Noble (1996)/laser

PARTICLE BEAM

1011 A/cm2 Chen & Noble (1987) (crystal OK for 10 fs)

Relativistic Channeling - Frascati March 23, 2004

situation for fermilab a0 photoinjector
Situation for Fermilab A0 photoinjector
  • A0 RF GUN FOR COMPARISON
      • I/cm2 = 10 nc/1 ps in 1 mm2 or 106 A/cm2 (OK driver @ 1GeV)
  • A0 LASER FOR COMPARISON
      • 10 W/cm3 slap ruptured (continuous, 1015W/cm3 for 10 fs)
      • 109 W/cm2 damage on lens
      • 1018 W/cm2 1 Joule on 10 μm spot in 1 ps (OK driver)

Relativistic Channeling - Frascati March 23, 2004

earlier high charge cr experiments
Earlier high charge CR experiments

Relativistic Channeling - Frascati March 23, 2004

fermilab a0 schematic layout

Faraday

cup

Spectrometer

magnet

ICT

goniometer

S1

Detector

1 m

Fermilab A0 schematic layout

Ne = 5*1010

ICT

R. Carrigan, et al. Phys. Rev. A68, 062901 (2003)

Relativistic Channeling - Frascati March 23, 2004

a0 at the goniometer

Goniometer

Spectrometer

A0 at the goniometer

10 nC peak, ε typically 10 mm*mrad, 10 ps

Relativistic Channeling - Frascati March 23, 2004

a0 x ray detector

Photo

tube

X-rays

Absorber

wheel

CaW

A0 x-ray detector

Also used a CaW CCD detector, AberX, developed at Darmstadt

by Joerg Freudenberger (Darmstadt thesis D17 - 1999)

and Sven Fritzler (Darmstadt Diplomarbeit - 2000)

Relativistic Channeling - Frascati March 23, 2004

planar and axial scans
Planar and axial scans

random

Relativistic Channeling - Frascati March 23, 2004

summary of high charge measurements
Summary of high charge measurements

σb is O(0.5 mm), length = > 7 ps (s)

Peak n/cm2 is 1013 electrons/cm2

I/cm2 = 105 A/cm2

flat is not ruled out

Fermilab

Relativistic Channeling - Frascati March 23, 2004

the future beyond the fermilab a0 experiment
The Future Beyond the Fermilab A0 Experiment
  • get into 10 fs regime
  • ne 103 to 105 larger (small beam size important)
  • higher energy might be better for channeling, beam size
    • But new experimental geometry, channeling approaches needed
  • Possibilities:

SLAC E164 geometry for channeling radiation at 30 GeV

Livermore

Toronto – studying laser melting with sub picosec electron diffraction

Need a real theory of dynamic channeling!

Relativistic Channeling - Frascati March 23, 2004

using slac e164 to study channeling

gamma detector

Crystal

Using SLAC E164 to study channeling
  • Add crystal, goniometer, x-ray det. (integrating). Now at FFTB (final foc TB) for big q.
  • Channeling radiation ala N. A. Filatova, Phys. Rev. Lett. 48, 488 @ 12 GeV, (1982), K. Kirsebom, et al., NIMB 119, 79 (96) @ 150 GeV.

Beam:

charge: 2*1010/bunch (< A0), size 25 mm.

time: 100 mm/c = 300 fs

I/cm2: 50*106 A/cm2 (500 times better than A0)

This could take channeling measurements nearly to the plasma regime.

C. Barnes et al., Proc. 2003 Particle Acc. Conf. 1530 (03)

Relativistic Channeling - Frascati March 23, 2004

high energy density application channeling with intense proton beam
High energy density application channeling with intense “proton beam”

flat focused

Protons

80-250 mm dia

1012 protons

4-12 MeV

Laser:

50 mm dia

5*1018 W/cm2

100 fs

Plasma

Temp O(4eV)

ns

mm

Instrument with streak camera, layers of radiochromic film, interferometer, etc.

Could one see channeling blocking patterns, RBS off of oriented target film

and study lattice properties as a function of pump and probe

or time evolution after hit? World class laser could give 1014 protons.

“Isochoric Heating…”, P. Patel, et al., PRL 91, 125004 (03) [Livermore]

Relativistic Channeling - Frascati March 23, 2004

toronto studying laser melting with sub picosec electron diffraction
Toronto - studying laser melting with sub picosec electron diffraction
  • See solid to liquid phase transition for electron diffraction in 0.02 mm polycrystalline aluminum foil heated with 7*1010 w/cm2 laser over 3.5 ps. Transition is electron – phonon coupling.

fcc lattice

liquid

B. Siwick, et al., Science 302, 1382 (03), D. Von der Linde, Science 302, 1345 (03)

Relativistic Channeling - Frascati March 23, 2004

the far future
The Far Future?

Channeling

Related

Accelerator

Project

Relativistic Channeling - Frascati March 23, 2004

fermilab a0 participants
Fermilab A0 Participants
  • R. A. Carrigan, Jr., J.-P. Carneiro, P. L. Colestock, H. T. Edwards,
  • W. H. Hartung, and K. P. Koepke
  • Fermi National Accelerator Laboratory
  • M. J. Fitch
  • University of Rochester
  • N. Barov
  • University of California at Los Angeles
  • J. Freudenberger, S. Fritzler, H. Genz, A. Richter, and A. Zilges
  • Institut für Kernphysik, Technische Universität Darmstadt,
  • J. P. F. Sellschop
  • Schonland Centre, University of the Witwatersrand

Relativistic Channeling - Frascati March 23, 2004