Stanislav Tachenov

1
Photocorrelation and polarization studies for
capture into high Z ions.
Stanislav Tachenov
Gesellschaft für Schwerionenforschung
(GSI)/Darmstadt and University of Frankfurt
in collaboration with
Experiment Th. Stöhlker, D. Banas, H.F. Beyer, G.
Bednarz, F. Bosch, A. Bräuning-Demian, R.W.
Dunford, A. Gumberidze, S. Hagmann, E. Kanter, O.
Klepper, C. Kozhuharov, D. Liesen, X. Ma, P.H.
Mokler, A. Muthig, F. Nolden, U. Spillmann, Z.
Stachura, A. Warczak, D.Proic, Th. Krings and the
ESR-Team Atomic Physics Group, GSI-Darmstadt,
Germany Argonne National Laboratory, Argonne,
USA Kansas State University, Kansas, USA IMP,
Lanzhou, China University of Cracow,
Poland University of Frankfurt,
Germany Forschungzentrum Jülich, Germany
Theory J. Eichler, S. Fritzsche, A. Ichihara,
D.C Ionescu, T. Shirai, A. Surzhykov   Theo
retische Physik, HMI-Berlin, Germany JAERI,
Japan TU-Dresden, Germany GSI-Darmstadt,
Germany University of Kassel, Germany
2
Photon-Matter Interaction in the Relativistic
Regime Radiative Electron Capture (K-REC)
Photoionization
Radiative Electron Capture
E
KIN
8
E
L
E
K
3
X-Ray Spectroscopy at the ESR
ESR
e- cooler
Particle energy up to 400 MeV/u for U 92 Energy
definition 10-4 with cooling Number of particles
108 per cycle
GAS JET
N2, Ar 1012p/cm3
4
Measurements with coincidences
90o
U92
60o
120o
35o
150o
Particle detector
U91
U92
Dipole magnet
Movable detector 4o 15o
coincidence measurement
5
Radiative Electron Capture Capture of
Quasifree Targetelectrons
U92 gt N2, 358 MeV/u
6
Total REC cross sections for bare ions
complete relativistic calculations for Au 79
(Eichler et. al)
dipole approximation
The simple non-relativistic dipole approximation
provides an accurate tool for cross section
preditions (below 1 GeV/u)
7
Experimental REC studies
performed up to now
8
Interaction of electro-magnetic
radiation with matter

• photoelectric effect
• Compton scattering
• pair production

9
Compton scattering
10
Polarization Measurements by Means of
Compton Scattering
Klein-Nishina formula
11
Segmented planar Ge detector
Pixel matrix 4x4 Pixel size 7x7 mm Energy
resolution 2 KeV
4 x 7 mm
15 mm
4 x 7 mm
D. Protic, FZ-Jülich
12
Compton scattered photons
13
First Polarization Measurement
for Radiative Recombination Transitions (U92
e- ? U91 hw )
?E
gas target
ion beam (400 MeV/u)
preliminary data from the ESR beam time May 2002
14
First Polarization Measurement
for Radiative Recombination Transitions (U92
e- ? U91 hw )
gas target
ion beam (400 MeV/u)
preliminary data from the ESR beam time October
2002
15
First Polarization Measurement
for Radiative Recombination Transitions (U92
e- ? U91 hw )
Polarization measurement is a precise method to
study relativistic contributions to KREC process
Theory S. Fritzsche, A. Surzhykov
16
Simulating of the detector responce
17
Simulating of the detector responce
A doppler shift within a single pixel
gas target
ion beam
18
Compton/Gamma Camera
double sided Ge(i) strip detector (3D position
sensitive) Improved geometry resolution
128 x 250 µm
1.8 cm
48 x 1.17 mm
D. Protic, FZ-Jülich
19
Approach to a 3D germanium detector
Measuring the drift time difference...
1.8 cm
...makes 2 dimensional stripe detector 3D
position sensitive
20
Compton/Gamma Camera
Reconstructing an Image of the ? source
(LBL, Burke et al. NRL Kroeger et al.)
21
(LBL, Burke et al. NRL Kroeger et al.)
22
NRL Advanced Compton Telescope
(LBL, Burke et al. NRL Kroeger et al.)
23
Detection of the ion beam polarization
Unpolarized ion beam
Polarized ion beam
hw
gas target
ion beam
24
A possible experiment for the ion beam
polarization and detection
ESR
Lifetime of the excited state 50 ms Laser
repetition rate 20 ms
Laser
NdYAG 532 nm doubled
Gas target
25
Summary
the first polarization measurement of the K-REC
radiation in relativistic regime was
performed Segmented Ge detectors provide an
excellent tool for polarization studies in the
hard X-Ray regime a new technique for the
telescopes development the unique instrument
for an ion beam polarization diagnostic