Electromagnetic processes in strong
crystalline fields, H4 Oct. ’07
J.U. Andersen, K. Kirsebom, S.P. Møller, A.H. Sørensen, U.I. Uggerhøj
Department of Physics and Astronomy, Aarhus University, Denmark
A. Apyan
Department of Physics and Astronomy, Northwestern University, Evanston IL, USA
P. Sona
Institute of Physics, Florence University, Italy
S. Ballestrero, S. Connell
Schonland Research Institute, Johannesburg, South Africa
T. Ketel
Science Department, Free University, Amsterdam, The Netherlands
M. Khokonov
Department of Physics, Kabardino-Balkarian State University, Nalchik, Russian Fed.
V. Biryukov, Yu. Chesnokov
Institute of High Energy Physics, Protvino, Russia
W. Greiner, A.V. Korol, A.V. Solov’yov
Frankfurt Institute for Advanced Studies, Johann Wolfgang Goethe University, Frankfurt, Germany
V. Baier
Budker Institute of Nuclear Physics, Novosibirsk, Russia
S. Kartal, A. Dizdar
Department of Physics, University of Istanbul, Turkey
A. Mangiarotti
Universidada de Coimbra, Coimbra, Portugal
Yu. Kononets
Kurchatov Institute, Moscow, Russia
Run in H4
Oct. 2007
Plans
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Trident ’Klein-like’ production
e+
e-
e-
Strong field
Kimball and Cue, Phys. Rep. 125, 69 (1985)
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Pair production LPM effect
Requires extreme
precision to
measure in
amorphous
materials for PP
1.0
0.8
Cross section
LPM:
Strong multiple
scattering within
formation length
leads to
suppression
0.6
0.4
0.1 TeV
1 TeV
10 TeV
0.2
Amorphous Ir
0.0
0.0
0.2
0.4
0.6
0.8
1.0
Fractional lepton energy, Ee /h
+
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Pair production LPM effect
Tungsten
Equivalent effect in
amorphous materials for
photon energies
 ≈ 5 TeV
Calculations underway
for Ge
The relative contribution of the LPM effect (in percent) in tungsten, axis< 111 >. Curve
1 is forT = 293 K and curve 2 is forT = 100 K.
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Crystal undulator
Solov’yov,
Greiner et al.
26.06.07
Not to scale
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Sandwich target
• Sandwich target
• 20 layers:
Ta – Al – Ta – Al – :
ZTa2/ZAl2= 32
• Resonances within
formation length
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Blankenbecler:
2 foils, 25 GeV
7
Motivation
(why still do QED experiments?)
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The critical (Schwinger) field
• Schwinger, 1949
Quantum corrections to synchrotron radiation emission
Relativistic invariant:
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Beamstrahlung
Electric field
from one bunch
boosted by 22
as seen by the
other
heavy ions
SLC:
χ (or )  10-3
Superstrong field,
but of short
duration
ILC:
χ (or )  1
E1s/E0 = 3Z3
Strong lasers
Extended nucleus:
Z  172
Laser wavelength (and
 energy) limited
by non-linear Compton
scattering
χ (or )  1
-collision scheme
(Telnov et al.)
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Spin-flip and beamstrahlung
35 GeV, =1.0
no spin
w/ spin
2.0
1.8
1.6
Power, dN/d
1.4
Blankenbecler and Drell, ”Quantum treatment of
beamstrahlung”, PRD 36, 277 (1987)
1.2
1.0
0.8
0.6
0.4
0.2
0.0
0.0
0.2
0.4
0.6
0.8
1.0
0.8
1.0
Fractional photon energy, =h/Ee
1.0
0.9
=100
0.8
Total
pure spin
no spin
dN/d [Arb.]
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
0.0
0.2
0.4
0.6
Fractional photon energy, =h/Ee
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Plasma
wakefields
Transverse focusing forces:
Lead to values
for realistic parameters:
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Magnetars
• Magnetars
• B  1010 T
• relativistic gyration:
ħ/mc2
= B/B0
T=0.01 MeV
T=15 MeV
• Electrosphere of
strange stars:
 ≈ 5-100
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Strong fields in
crystals
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Strong crystalline fields
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Crystals
Extremely strong
electric fields
50 V / 0.1 Å
=
5·1010 V/cm
1010-1011 V/cm
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Klein’s
paradox
• Reflection
coefficient
approaches 0
beyond the
critical field:
Pair production.
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Crystal
undulator
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Crystal undulator
Not to scale
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Femtosecond laser-ablated crystals
10 microns, laser
200 microns,
diamond-blade
(state-of-the-art,
2003)
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Solov’yov,
Greiner et
al.
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MBE grown crystal
Undulator
0.6
% Ge in Si
0.5
0.4
Series1
Series2
0.3
0.2
0.1
0
0
10
20
30
40
50
60
70
80
0,3 mm steps
1.5 MeV proton RBS, 0.3 mm beamspot
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X-ray measurements
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Run in H4
Oct. 2007
Setup
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H4 zone
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Pair spectrometer zone (photons)
DC3
DC5 DC6
DC4
MDX
LG
Target
He-tank
All signal and HV cables and DC gas piping has been installed during week 24
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Pair spectrometer zone (trident)
DC5 DC6
DC3
vacuum
MDX
LG
Target
He-tank
26.06.07
Roll out He-bag, install
vacuum
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Financing and manpower
Money:
• Essentially all the equipment is existing and has been
tested to be fully functioning
• Travel and accomodation (for the danish/german/italian
groups) have an allocated budget of about 60 kCHF from
FP6, STREP/NEST funding.
Manpower:
• 3 staff members, 3 technicians and 3 students from
Aarhus
• Similar numbers from the participants from Italy and
South Africa.
• Dutch, German, Russian and Turkish participants active
during the run, but with fewer persons.
• About 20 active members during the beam time,
excluding students.
We are ready for the October run.
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Formation length
• Underlying concept for all our proposed expts.
Example: 250 GeV electron emitting 1 GeV photon: lf = 0.1 mm
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Sandwich target – H4, Oct. 2006
Preliminary
Intensity per electron
0.003
0.002
0.001
5 m Ta, 6 m Al
10 m Ta, 30 m LDPE
200 m Ta
0.000
2
4
6
8
10
12
14
16
18
20
Photon energy [GeV]
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Quantum-synchrotron
Thin target (negl. energy loss)
Thick target, 0.2 mm W, NA43 data
K. Kirsebom et al.
Phys. Rev. Lett. 87 (2001) 054801
V.N. Baier and V.M. Katkov
Phys. Lett. A 353, 91 (2006)
γ2/3/γ2  2/3/2
Classical = linear
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Electromagnetic processes in strong
crystalline fields, H4 Oct. ’07
J.U. Andersen, K. Kirsebom, S.P. Møller, A.H. Sørensen, U.I. Uggerhøj
Department of Physics and Astronomy, Aarhus University, Denmark
A. Apyan
Department of Physics and Astronomy, Northwestern University, Evanston IL, USA
P. Sona
Institute of Physics, Florence University, Italy
S. Ballestrero, S. Connell
Schonland Research Institute, Johannesburg, South Africa
T. Ketel
Science Department, Free University, Amsterdam, The Netherlands
M. Khokonov
Department of Physics, Kabardino-Balkarian State University, Nalchik, Russian Fed.
V. Biryukov, Yu. Chesnokov
Institute of High Energy Physics, Protvino, Russia
W. Greiner, A.V. Korol, A.V. Solov’yov
Frankfurt Institute for Advanced Studies, Johann Wolfgang Goethe University, Frankfurt, Germany
V. Baier
Budker Institute of Nuclear Physics, Novosibirsk, Russia
S. Kartal, A. Dizdar
Department of Physics, University of Istanbul, Turkey
A. Mangiarotti
Universidada de Coimbra, Coimbra, Portugal
Yu. Kononets
Kurchatov Institute, Moscow, Russia