1 Studying and Applying Channeling at Extremely High Bunch Charges Dick Carrigan Fermilab...

1

Studying and Applying Channeling at Extremely High

Bunch Charges

Dick CarriganFermilab

International Workshop on Relativistic Channeling and Related

Coherent PhenomenaMarch 23, 2004, Frascati, Italy

Relativistic Channeling - Frascati March 23, 2004Fermilab channeling (Carrigan)

The dream of crystal channeling

(Aarhus)


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!”


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

Problem-transit time

Get out 1 keV/Å in 1 cm would get 100 GeV

Need an x-ray laser (1968)


Visionary possibilities for acceleration

Lasers R. Palmer, Particle Accelerators V11, 81 (1980). Recent

progress Kimura et al. PRL 92, 054801 (2004). See also LEAP at Stanford (Colby)

Would like much higher accelerating gradients

Two thoughts:

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)


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)

Pseudo solid state accelerators

3*1020 W/cm2, 1000 TW, 1013 proton beams with E to 58 MeV, electrons protons can be focused by curving targetprocess: electrostatic fields produced by ponderomotively accelerated hot electrons act on protons from absorbed hydrocarbons rear side (downstream)

+ -

+ -

+ -

Laser Debye Protons sheath

wedge

Livermore


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

RF cavity 0.0005 GV/cmgaseous plasma 1 GV/cmsolid state plasma 100 GV/cm

Plasma wake field acceleration

Photo S. Carrigan


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. Hogan Phys. Plasmas 7, 2241 (2000)


Results from SLAC E-157

Barov and Rosenzweig (UCLA) see similar results at Fermilab. 100 MeV/m using A0 14 MeV photoinjector. 6-8 nC, ne ~ 1014/cc.

Acceleration

M. Hogan Phys. Plasmas 7, 2241 (2000)


Basic Crystal Accelerator Concept

Big problems! blow away material dechanneling

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

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


The Fermilab A0 photoinjector

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?

• 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


Crystal survivability?

excite electronic plasmatunnel ionization

partial or total lattice ionization

piepi mm 2/1)/(

crystal disorder, fracture, or vaporizationlattice dissociation via

plasmon absorptionlifetime: (ion plasma frequency)-1

vaporization O(10-100 fs)hydrodynamic heating O(1-10 ps) [Livermore]

2/120 /4 ep men

electronic plasma decayvia interband transitionslifetime: (plasma frequency)-O(fs)excitation of phonons in lattice

Process


Intense beam through crystal could blow away electrons in much less than a picosecond

Acts like a larger screening length

Dynamic channeling

20

2

22

2

22

20

2/1

2lnln

2lnln

2 rCa

uCa

u

r

TF

TFL Andersen 96

0

0.5

1

1.5

2

0 0.5 1 1.5Screen length (Angstroms)

Rela

tive

criti

cal a

ngle

300 K

0

0.5

1

1.5

2

0 500 1000 1500 2000Temperature (K)

Rre

lati

ve c

riti

cal angle screening = 1.5

screening = 0.2


Crystal destructionACCELERATION

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/cmLASER

1011 W/gm Belotshitkii & Kumakhov (1979) or 106 a/cm2 for particle beam1012 W/cm3 ns long pulses1013 W/cm3 Chen-Noble (1987) fracture threshold O(0.1 ns) ref 16Skin depth < 0.1 mm

PARTICLE BEAM1011 A/cm2 Chen & Noble (1987) (crystal OK for 10 fs)

LATTICE IONIZED1015-1016 W/cm2 Chen & Noble (1996)/laser


A0 RF GUN FOR COMPARISONI/cm2 = 10 nc/1 ps in 1 mm2 or 106 A/cm2 (OK driver @

1GeV)

A0 LASER FOR COMPARISON10 W/cm3 slap ruptured (continuous, 1015W/cm3 for

10 fs)109 W/cm2 damage on lens1018 W/cm2 1 Joule on 10 μm spot in 1 ps (OK driver)

Situation for Fermilab A0 photoinjector


Earlier high charge CR experiments

0 100

2 10-5

4 10-5

6 10-5

8 10-5

1 10-4

1.2 10-4

1.4 10-4

1 100 104 106 108 1010 1012

n/bunch

conjecture for dynamic channeling

30 MeV Si(110) over .5 cm2 on Si(110) (triangle) Gary et al., PR B42, 7 (1990)

5.4 MeV Diamond <110>, sig = 0.8 mm (blk dot) Genz et al., APL 57, 2956 (90)


ICTICT goniometer S1

Spectrometer

magnet

Faraday

cup

Detector

1 m

Ne = 5*1010

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

Fermilab A0 schematic layout


A0 at the goniometer

10 nC peak, ε typically 10 mm*mrad,

10 ps

Goniometer Spectrometer


A0 x-ray detector

Also used a CaW CCD detector, AberX, developed at Darmstadtby Joerg Freudenberger (Darmstadt thesis D17 - 1999)and Sven Fritzler (Darmstadt Diplomarbeit - 2000)

CaWAbsorber

wheel

X-raysPhototube


4

5

6

7

8

-20 0 20 40 60 80 100Q

y(mrad)

(100) (110) (100)

0

4

8

12

16

-40 -20 0 20 40 60 80

y = 9.6615 - 0.024802x R2= 0.84092

Qx (mrad)

y = m1+m2*m0+m3*exp(-((m0-m4...

ErrorValue

0.14415.905m1

0.0019399-0.012444m2

0.302254.5175m3

0.157629.3948m4

0.283543.8981m5

0.246862.4271m6

1.704214.486m7

NA0.64401Chisq

NA0.99298R2

<100>

Planar and axial scans

random


1.E-04

1.E+00

1.E+04

1.E+08

1.E+12

1.E+00 1.E+04 1.E+08 1.E+12 1.E+16

e/bunch

x-ra

ys/b

un

ch (

10%

en

ergy

ban

d)

Summary of high charge measurements

• σb is O(0.5 mm), length = > 7 ps ()

• Peak n/cm2 is 1013 electrons/cm2

• I/cm2 = 105 A/cm2

• flat is not ruled outFermilab


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 GeVLivermoreToronto – studying laser melting with sub picosec electron diffraction

Need a real theory of dynamic channeling!


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.

Crystalgamma detector

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

Beam:

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

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.


High energy density application channeling with intense “proton beam”

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

flat focused

ns

m

Laser: 50 m dia5*1018 W/cm2

100 fs

Protons80-250 m dia1012 protons4-12 MeV

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.

PlasmaTemp O(4eV)


Toronto - studying laser melting with sub picosec electron diffraction

See solid to liquid phase transition for electron diffraction in 0.02 m polycrystalline aluminum foil heated with 7*1010 w/cm2 laser over 3.5 ps. Transition is electron – phonon coupling.

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

fcc lattice

liquid


The Far Future?

Channeling

Related

Accelerator

Project


Fermilab A0 Participants

R. A. Carrigan, Jr., J.-P. Carneiro, P. L. Colestock, H. T. Edwards,

W. H. Hartung, and K. P. KoepkeFermi National Accelerator Laboratory

M. J. FitchUniversity of Rochester

N. BarovUniversity of California at Los Angeles

J. Freudenberger, S. Fritzler, H. Genz, A. Richter, and A. ZilgesInstitut für Kernphysik, Technische Universität Darmstadt,

J. P. F. SellschopSchonland Centre, University of the Witwatersrand

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