X-ray and γ-ray polarimetry Stanislav Tashenov KTH Stockholm
X-ray and γ-ray polarimetry
Stanislav TashenovKTH Stockholm
OutlineOutlineDefinitions
Photon Polarimetry - Short Overview
Principle – Klein-Nishina formulaPixel Detector – coincident technique
Experimental study of the polarization of Radiative Recombination
From experimental setup till results
Summary
Compton Polarimetry of hard X-rays
New developments of Compton polarimeters for “low” energies (few 100 keV)
Extension of Compton polarimetry to higher energies, tracking (till few 10 MeV)
Compton circular polarimetry
Other types of polarimeters
PhotoelectricPair productionCrystalline
What is photon polarization?Classical: polarization of electromagnetic waves
linear:
Quantum Mechanical: photon helicity
112
1sincos
ii
yx eeeee
S S
λ = 1 λ = -1
circular:
λ = 1 λ = -1
112
1 xe
112
iey
Linear polarization – superposition of states with opposite helicities
What is partial photon polarization?
Mixed state is described by a density matrix:
Linear polarization components:
Circular:
polarization ellipse
Stokes parameters
Rayleigh (elastic) scattering
Wollaston and otherprisms
Photon polarimetry & imaging
energy, ev
1 1e4 1e510 100 1e30.1
Birefringence effect
Linear dichroism
LCD
IR visible light UV soft X-ray X-ray hard X-ray gamma →
Bragg reflection
Photoabsorption
x-ray optics
Micropattern gascounters
Thomson scattering
CCD cameras
Segmented solidstate detectors
Chandra X-ray image of Crab Nebula
and Compton scattering
Photon polarimetry & imaging
energy, ev
Photon polarimetry & imaging
energy, ev
1e4 1e5 1e6 1e7 1e8 1e9
IR visible light UV soft X-ray X-ray hard X-ray gamma →
Photoabsorption
Thomson scattering
CCD cameras
Segmented solidstate detectors
and Compton scattering
Pair production
Birefringencein CPP
AGATA,GRETA
AdvancedComptonTelescope
OutlineOutlineDefinitions
Photon Polarimetry - Short Overview
Principle – Klein-Nishina formulaPixel Detector – coincident technique
Experimental study of the polarization of Radiative Recombination
From experimental setup till Results
Summary
Compton Polarimetry of hard X-rays
New developments of Compton polarimeters for “low” energies (few 100 keV)
Extension of Compton polarimetry to higher energies, tracking (till few 10 MeV)
Compton circular polarimetry
Other types of polarimeters
PhotoelectricPair productionCrystalline
0 30 60 90 120 150 180
ener
gy
(KeV
)
scattering angle c (deg)
2/m keV 240ω 2ec
0
48
96
144
192
240
2/m keV 350ω 2ec
0
70
140
210
280
350
recoil electron
scattered photon
)cos1(1'
2 cecm
e-
c
100 101 102 103 104 10510-4
10-3
10-2
10-1
100
101
102
103
104
atte
nuat
ion
1/cm
energy (KeV)
Ge energy absorption
Photabsorption
ComptonPair Production
TotalK
L
Compton scattering
0
30
60
90
120
150
180
210
240
270
300
330
E
´
E
Klein-Nishina equation
)cos θsin2'
'()
'(
2
1 22220
rd
d
Compton polarimetry
090
090
M
Modulation
0 30 60 90 120 150 1800.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0 0.01 MeV 0.1 MeV 1 MeV 10 MeV
scattering angle, deg
Differential cross section
Modulation
coincidence
Eel
E= E= el + 50 100 150 200 250 300
0
5000
10000
15000
20000
25000
Ly
energy (KeV)
Ly
K-R
EC
L-R
EC
M-,
N-.
. R
EC
single pixel spectrum
50 100 150 200 250 300048
12
energy (KeV)
50 100 150 200 250 300048
12recoil electron
Compton photon
4 x 7 mm 15 m
m
4 x
7 m
m
50 100 150 200 250 3000
1000
2000
3000
4000K-REC
L-RECM,..-REC
energy (KeV)
coincident sum spectrum
Segmented detectors – coincidence technique
)cos1(1'
2 cecm
e-
c
0 30 60 90 120 150 180
ener
gy (
KeV
)
scattering angle c (deg)
2/m keV 240ω 2ec
0
48
96
144
192
240
2/m keV 350ω 2ec
0
70
140
210
280
350
recoil electron
scattered photon
Compton kinematics
For higher energies the reconstruction is more difficult → Tracking is required
OutlineOutlineDefinitions
Photon Polarimetry - Short Overview
Principle – Klein-Nishina formulaPixel Detector – coincident technique
Experimental study of the polarization of Radiative Recombination
From experimental setup till results
Summary
Compton Polarimetry of hard X-rays
New developments of Compton polarimeters for “low” energies (few 100 keV)
Extension of Compton polarimetry to higher energies, tracking (till few 10 MeV)
Compton circular polarimetry
Other types of polarimeters
PhotoelectricPair productionCrystalline
Radiative RecombinationRadiative Recombination
Time Reversal
Photoionization
e-
h
Radiative Electron Capture
8
E L
E K
E KIN
e-
h
30 60 90 120 150 1800
20
40
60
80
100
120
140
160
M-R
EC
K-R
EC
L-R
EC
Ly1
Ly2
+
M1
cou
nts
energy (KeV)
U92+ → N2 collision at 310 MeV/u150○ observation angle
Photon PolarizationPhoton Polarization
E
B
e- Electron is ejectedalong the electric field
Nonrelativistic dipoleapproximation
E
B
e-
E
B
e- Electron is ejectedalong the electric field
Nonrelativistic dipoleapproximation
e-
E
Radiative Electron Capture Photoionization
non-relativistic dipole approximation: 100 % polarization for all emission angles
K-REC photon polarizationK-REC photon polarization
0 30 60 90 120 150 180-0.50
-0.25
0.00
0.25
0.50
0.75
1.00
1.25
degr
ee o
f lin
ear
pola
rizat
ion
angle (deg)
0 30 60 90 120 150 180-0.50
-0.25
0.00
0.25
0.50
0.75
1.00
1.25
300 MeV 500 MeV 800 MeV
degr
ee o
f lin
ear
pola
rizat
ion
angle (deg)
K-REC into bare uranium ions(U92+ + e- U91+ + ħω ) non-relativistic
dipole approximation:100 % polarizationfor all emission angles
Large relativistic contributions
J. Eichler et al., PRA, 65 (2002) 052716A. Surzykov et al., Phys. Lett. A 289 (2001) 213A. Surzykov et al., PRA 68 (2003) 022710
E
B
e- Electron is ejectedalong the electric field
Nonrelativistic dipoleapproximation
E
B
e-
E
B
e- Electron is ejected
e-
e-
along the magnetic fieldalong the electric field
e- cooler
GAS JET
∙ U92+ stored at energies of 98.4, 132.2, 190.0, 400.0 MeV/u∙ Number of stored particles 1 to 3x108
∙ Energy definition 10-4 with cooling
GAS JETN2 1012 p/cm2
SIS injection400 MeV/u
Particledetector
90o
60o
REC measurement at the ESR storage ring
ion beam (400 MeV/u)
targ
etga
s
K-REC
ESR storage ring
I∥
I⊥
100 150 200 250 3000
5
10
15
20
25
30
coun
ts
energy (KeV)
I⊥
I∥
Experiment:Polarization Measurement for RadiativeRecombination Transitions (U92+ + e- U91+ + ħω )
90º 90○ rotational symmetry of the detector
0 60 120 180 240 300 3600
1
2
3
4
5
6
7
8
9
norm
aliz
ed in
tens
ity I
/I
scattering angle (deg)
Degree of Linear Polarizationfor ideal (pointlike) detectors
100% 80% 40%
0 60 120 180 240 300 3600
2
4
6
8
10
12
14
16
scattering angle (deg)
scat
terin
g in
tens
ity I
0 60 120 180 240 300 3600.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
norm
aliz
ed in
tens
ity I
/I
scattering angle (deg)
Result (400 MeV/u, 90o observation angle)degree of linear polarization:polarization angle:
0.79 ± 0.080o ± 3o
0
30
60
90
120
150
180
210
240
270
300
330
Compton scattering angular distribution: Internal normalization
Monte-Carlo simulation describingthe detector response to polarized light
e-
c
Z=14±1 mm
Compton profile
Rayleigh scattering
Statistical error ±4 % up to ±12 %
Overall error is dominated by the statistical uncertainty
Multiple Compton scattering
Detector geometry
All systematic effects ±2 % up to ±3 %
---
< +0.5 %
±2 % up to ±3 %
---
estimated uncertainty:
(+1.3 % shift)
(detector depletion depth)
0 30 60 90 120 150 180-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
100 MeV/u 400 MeV/u 800 MeV/u
degr
ee o
f lin
ear
pola
rizat
ion
observation angle lab
(deg)
Angular dependence
100 200 300 400 5000.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
degr
ee o
f lin
ear
pola
rizat
ion
projectile energy (MeV/u)
Energy dependence
θ=60o
Uranium (Z=92)Results
S. Tashenov et al., PRL 97 (2006) 223202
Ψion beam
E
S
Ion beam spin polarizationIon beam spin polarization
0 30 60 90 120 150 180-0.2
0.0
0.2
0.4
0.6
0.8
1.0
Stokes Parameters P
1
P2
degre
e o
f lin
ear
po
lari
zatio
n
angle (deg)
Uranium 500 MeV/u
1
22tan PP
degree of ion beamspin polarization⇒
A.Surzhykov et al., PRL 94 (2005) 203202
OutlineOutlineDefinitions
Photon Polarimetry - Short Overview
Principle – Klein-Nishina formulaPixel Detector – coincident technique
Experimental study of the polarization of Radiative Recombination
From experimental setup till results
Summary
Compton Polarimetry of hard X-rays
New developments of Compton polarimeters for “low” energies (few 100 keV)
Extension of Compton polarimetry to higher energies, tracking (till few 10 MeV)
Compton circular polarimetry
Other types of polarimeters
PhotoelectricPair productionCrystalline
Further developments of Compton polarimeters
Optimization for lower energies (~60 keV)
2D Si(Li) stripe detector2 mm stripe width
0 50 100 150 200 250 300 350 4000.00
0.25
0.50
0.75
1.00
energy, keV
Si
Ge
Com
pton
/to
tal
100 101 102 103 104 10510-4
10-3
10-2
10-1
100
101
102
103
104
atte
nuat
ion
1/cm
energy (KeV)
Ge energy absorption
Photabsorption
ComptonPair Production
TotalK
L
stack of 10 DSSD2 mm stripe width
Further developments of Compton polarimeters
Increased segmentation for betterpolarization sensitivity
2D Ge μ-stripe detector0.25 x 1.2 mm stripe width
)cos1(1'
2 cecm
)cos θsin2'
'()
'(
2
1 22220
rd
d
´
E
Scattering angle θ is selected by theenergy condition 30 45 65 90 115 135 150 165
205 188 170 149 133 123 119 116 energy [keV]
scattering angle [deg]
Preliminary results: 210 keVTest experiment at ESRF, 2005
Further developments of Compton polarimeters
3D position sensitivity achievedby means of digital signal processing
Pulse Shape Analysis2D pixel detector with10 mm pixel size →1 ÷ 3 mm 3D position resolution
0 60 120 180 240 300 3600.0
0.5
1.0
1.5
2.0
2.5
norm
aliz
ed in
tens
ity
scattering angle, deg
KTH Stockholm Ge 5 x 5 pixel detector10 mm pixel size equipped with digitalpulse sampling electronics
Laboratory calibrationas a polarimeterpreliminary results
OutlineOutlineDefinitions
Photon Polarimetry - Short Overview
Principle – Klein-Nishina formulaPixel Detector – coincident technique
Experimental study of the polarization of Radiative Recombination
From experimental setup till results
Summary
Compton Polarimetry of hard X-rays
New developments of Compton polarimeters for “low” energies (few 100 keV)
Extension of Compton polarimetry to higher energies, tracking (till few 10 MeV)
Compton circular polarimetry
Other types of polarimeters
PhotoelectricPair productionCrystalline
100 101 102 103 104 105
10-4
10-3
10-2
10-1
100
101
102
103
104
atte
nuat
ion
1/cm
energy (KeV)
Ge energy absorption
Photabsorption
ComptonPair Production
TotalK
L
Extension to higher energies
0.1 1 100
10
20
30
40
50
60
even
ts, %
enegy, MeV
multiplicity: 1 2 3 4 5 8 12 20
Gamma-ray trackingis required
0.0 0.5 1.0 1.5 2.0
100
1000
10000
coun
ts
energy, MeV
h = 2 MeV
eventstotaleventsphotopeaktotalpeak /
Solution: BGO shielding orClose-packed geometry
How well do the scattering angles fit with the corresponding deposited energies?
Tracking principle
)cos1(1'
2 cecm
Performance of tracking
0.0 0.5 1.0 1.5 2.00
50
100
150
200
250
coun
ts
energy, MeV
0.0 0.5 1.0 1.5 2.0100
101
102
103
104
105
coun
ts
energy, MeV0.5 1.0 1.5 2.0
100
101
102
103
104
105
coun
ts
energy, MeV0
Tracking can:1) determine the sequence of the scatterings2) verify the full energy deposition3) obtain the initial energy for the escape events
initial spectrum full energy events
escape events
Gamma arrays for nuclear physics based on tracking principles
AGATA (EU)GRETA (US)
DESPEC (GSI, darmstadt)
J. Simpson, J. of Phys.: Conf. Ser. 41 (2006) 72-80I.Y. Lee et al., Nucl. Phys. A 746 (2004) 255c-259c
Application of linear polarization:
radiation from aligned excited states - Identification of electric and magnetic transitions
g-factor measurements – time variation of linear polarization
J. Rikovska, Hyperf. Int. 24-26 (1985) 963G.J. Schmid et al., NIMA 417 (1998) 95
Gamma arrays for astrophysics
Nuclear Compton Telescopeballoon-borne mission
Advanced Compton Telescopespace mission
S.E. Boggs, P. Jean, Astronomy and Astrophysics 376 (2001) 1126J.D. Kurfess et al., New Astronomy Reviews 48 (2004) 293
„Gamma-ray polarization will be used to study theemission processes in GRBs, pulsars, AGN, andsolar flares—opening a new dimension indiagnostic phase space.“
(27 layers of Si and 4 layers of Ge)(12 Ge detectors)
OutlineOutlineDefinitions
Photon Polarimetry - Short Overview
Principle – Klein-Nishina formulaPixel Detector – coincident technique
Experimental study of the polarization of Radiative Recombination
From experimental setup till results
Summary
Compton Polarimetry of hard X-rays
New developments of Compton polarimeters for “low” energies (few 100 keV)
Extension of Compton polarimetry to higher energies, tracking (till few 10 MeV)
Compton circular polarimetry
Other types of polarimeters
PhotoelectricPair productionCrystalline
Compton circular polarimetry
Circularly polarized light couples only to spin-oriented electrons
W.H.McMaster, Review of Modern Physics 33 No.1 (1961) 8
03
02
01
0
3
2
1
P
P
P
I
T
P
P
P
I
k, k0 – final and initial photon energiesk, k0, S – photon and electron momenta
Compton circular polarimetry:technical realization
H. Schopper, Nuclear Instruments 3 (1958) 158L.W. Fagg, S.S. Hanna, Review of Modern Physics 31 No.3 (1959) 711
2 out of 26 electronsof Fe can be spin oriented
for Compton scatteringthe opposite spins of theelectron and the photon are preferable
Compton circular polarimetry:examples of applications
E.G. Adelberger, Ann. Rev. Nucl. Part. Sci. 35 (1985) 501W.C. Haxton, C.E. Wieman, Annu. Rev. Nucl. Part. Sci. 51 (2001) 261L. N. Labzowsky et al., PRA 63 (2005) 054105M.J. Cooper et al., Radiation Physics and Chemistry 75 (2006) 1638F. Lei et al., Space Science Reviews 82 (1997) 309J.C. Kemp, The Astrophysical Journal 162 (1970) 169
Studies of parity violation and tests of the standard model of elementary particlesNeutrino helicity (Goldhaber experiment)Astrophysics: light emission from strongly magnetized media
Magnetic Compton scattering:measurements of spin distributions in magnetic researchThomson scattering off relativistic electron beams to determine its properties
OutlineOutlineDefinitions
Photon Polarimetry - Short Overview
Principle – Klein-Nishina formulaPixel Detector – coincident technique
Experimental study of the polarization of Radiative Recombination
From experimental setup till results
Summary
Compton Polarimetry of hard X-rays
New developments of Compton polarimeters for “low” energies (few 100 keV)
Extension of Compton polarimetry to higher energies, tracking (till few 10 MeV)
Compton circular polarimetry
Other types of polarimeters
PhotoelectricPair productionCrystalline
Photoelectric polarimeters~ 1 up to few 10 keV
E. Costa et al., Nature 411 (2001) 662R. Bellazzini et al., NIMA A 576 (2007) 183
Photoelectric polarimeters~ 1 up to few 10 keV
R.P. Pratt et al., “Polarization correlations in atomic photoeffect”, Phys. Rev. 134 No 4a (1964) 916
Cross over happens at muchhigher energies
non-relativisticdipole approximation:100 % polarizationfor all emission angles
E
B
e- Electron is ejectedalong the electric field
Nonrelativistic dipoleapproximation
E
B
e-
E
B
e- Electron is ejected
e-
along the magnetic field
Pair production polarimeters~ few MeV up to ~ 1 GeV
P.F. Bloser et al., arXiv:astro-ph/0308331 (2003)
Problem at lower energies:angle straggling of electronsand positrons in solids
Solution:Gas micro well detectors
Crystalline polarimeters> few GeV
N. Cabibbo, PRL 9 (1962) 270N. Cabibbo, PRL 9 No10 (1962) 435
U. Uggerhoj Rev. Mod. Phys. 77 (2005) 1131A. Apyan et al., arXiv:hep-ex/0512017 v1 (2005)
In collaboration with...
...the end.
Th. StöhlkerD. BanasA. GumberidzeA. MuthigR. ReuschlU. SpillmannM. TrassinelliS. Trotsenko
GSI, Darmstadt
Experiment
A. Surzhykov S. Fritzsche
GSI, Darmstadt
Theory
D. ProicTh. Krings
FZ-Jülich
Detectors
J. Eichler
Hahn-Meitner-Institut Berlin
Theory
J. Gerl
GSI, Darmstadt
Experiment
R. SchuchS. Bohm
Uni. Stockholm
Experiment
EBIT
nuclear γ-spec
Bo CederwallA. Khaplanov
KTH Stockholm
Experiment
nuclear γ-spec
ESR
Bragg polarimetry
P. Soffitta et al., "Techniques and detectors for polarimetry in X-ray astronomy" NIMA 510 (2003) 170
E.E. Alp et al., "Polarizer–analyzer optics" Hyperfine Interactions 125 (2000) 45
P. Beiersdorfer et al., "Polarization of K-shell x-ray transitions of Ti19+ and Ti20+ excited by an electron beam" PHYSICAL REVIEW A 60 (1999) 4156
Photoelectric polarimetry
R. Bellazzin et al., "A photoelectric polarimeter for XEUS: a new window in x-ray sky" arXiv:astro-ph/0609571v1 (2006)
E. Costa et al., "An efficient photoelectric X-ray polarimeter for the study of black holes and neutron stars" Nature 411 (2001) 662
E. Costa et al., "OPENING A NEW WINDOW TO FUNDAMENTAL PHYSICS AND ASTROPHYSICS: X-RAY POLARIMETRY" arXiv:astro-ph/0603399 (2006)
J.K. Black et al., "X-ray polarimetry with an active-matrix pixel proportional counter" NIMA 513 (2003) 639
Compton polarimetry
F. Lei et al., "Compton polarimetry in gamma-ray astronomy" Space Science Reviews 82 (1997) 309–388
M.L. McConnell, J.M. Ryan "Status and prospects for polarimetry in high energy astrophysics" New Astronomy Reviews 48 (2004) 215–219
Hiroyasu Tajima et al.,"Gamma-ray Polarimetry with Compton Telescope" (2004) arXiv:astro-ph/0407114
R.A. Kroeger et al., "Gamma ray polarimetry using a position sensitive germanium detector" NIMA 436 (1999) 165
L.W. Fagg "Polarization measurements on nuclear gamma rays" Review of Modern Physics 31 No3 (1959) 711
W. McMaster "Matrix representation of polarization" Review of Modern Physics 33 No1 (1961) 8
G.J. Schmid et al., "Gamma-ray polarization sensitivity of the Gammasphere segmented germanium detectors" NIMA 417 (1998) 95
J.H. Lee et al., "Polarization sensitivity and efficiency for a planar-type segmented germanium detector as a Compton polarimeter" NIMA 506 (2003) 125
J. Rikovska, "Gamma-ray linear polarization measurements on oriented nuclei" Hyperfine Interactions 24-26 (1985) 963
Dan Xu et al., "Detection of Gamma Ray Polarization Using a 3-D Position-Sensitive CdZnTe Detector" IEEE TRANSACTIONS ON NUCLEAR SCIENCE, VOL. 52, NO. 4, (2005) 1160
S. Tashenov et al., "First Measurement of the Linear Polarization of Radiative Electron Capture Transitions" Physical Review Letters, 97, 223202 (2006)
Circular Compton polarimetry
H. Schopper, "Measurement of circular polarization of gamma-rays" Nuclear Instruments 3 (1958) 158
L.W. Fagg "Polarization measurements on nuclear gamma rays" Review of Modern Physics 31 No3 (1959) 711
R.M. Steffen, Physical Review 118 No.3 (1960) 763-767
R.E. Pechacek et al., Review of Scientific Instruments 35 No.1 (1964) 58-63
R.D.L. Mackie, J. Byrne, Nuclear Instruments and Methods 76 (1969) 241-244
W. Trautmann et al., Physical Review Letters 39 No.17 (1977) 1062-1065
T.F. Fazzini et al., Nuclear Instruments and Methods 192 (1982) 287-290
V.A. Kniaz'kov et al., Nuclear Physics A 417 (1984) 209-230
Pair production polarimetry
M. Kobayashi et al., "New method for measurement of gamma-ray polarization by detection of angular correlation in pair production" NIM 104 (1972) 101
P.F. Bloser et al., "A Concept for a High-Energy Gamma-ray Polarimeter" arXiv:astro-ph/0308331 (2003)
B. Wojtsekhowski et al., "A pair polarimeter for linearly polarized high-energy photons" NIMA 515 (2003) 605
Crystalline polarimetry
N. Cabibbo et al., "New method for producing and analyzing linearly polarized gamma-ray beams" Physical Review Letters 9 no6 (1962) 270
N. Cabibbo et al., "Circular polarization of high-energy gamma-rays by birefringence in crystals" Physical Review Letters 9 no10 (1962) 435
U. Uggerhoj "The interaction of relativistic particles with strong crystalline fields" Review of Modern Physics 77 (2005) 1131
A. Apyan et al., "Coherent Bremsstrahlung, Coherent Pair Production, Birefringence and Polarimetry in the 20-170 GeV energy range using aligned crystals" arXiv:hep-ex/0512017 v1 (2005)
http://www-linux.gsi.de/~tachenov/research/talks/polarimetry.pdf
X-ray polarimetry publications
Thank you for your patience!