measurement of atomic parameters at lnhb m arie -c hristine lépy and y ves ménesguen...
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Measurement of ATOMIC PARAMETERS AT LNHB M arie -C hristine Lépy and Y ves Ménesguen Laboratoire National Henri Becquerel France. DDEP meeting – 08/10/2012. Pour insérer une image : Menu « Insertion / Image » ou Cliquer sur l’icône de la zone image . ATOMIC PARAMETERS. - PowerPoint PPT PresentationTRANSCRIPT
MEASUREMENT OF ATOMIC PARAMETERS
AT LNHB
Marie-Christine LÉPY and Yves MÉNESGUEN
LABORATOIRE NATIONAL HENRI BECQUEREL
FRANCE
DDEP MEETING – 08/10/2012 | PAGE 1
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ATOMIC PARAMETERS
INTRODUCTION
INTERNATIONAL INITIATIVE
ATTENUATION COEFFICIENTS
FLUORESCENCE YIELDS (Ge)
PHOTON EMISSION INTENSITIES (241Am)
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INTRODUCTION
Use of atomic parameters in decay data -> X-ray emission intensities
Fluorescence yields
Relative intensitiesKb/Ka, Ka2/Ka1, etc.
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X-RAY DATA
55Fe decays by electron capture
Example : 55Fe
𝑈 𝑅(𝐼 𝑋𝐾 )=√𝑈 𝑅❑2 (𝑃𝐾 )+𝑈 𝑅
❑2(𝜔𝐾)
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X-RAY DATA
Photon emission intensities ->
-> Calibration of semi-conductor detectors (X-ray spectrometry)
-> Determination of photon emission intensities
-> New results depend on the fluorescence yields and relative photon emission intensities …
Application
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INTERNATIONAL INITIATIVE
International initiative on x-ray fundamental parameters
Launched in 2008 (EXRS conference)
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INTERNATIONAL INITIATIVE Motivation
• Parameters useful for quantitative x-ray analysisStrong demand of users from many application fields : innovative materials, archaeometry, environment, chemistry, etc.
Tables – reliability – uncertainties ?
Lack of recent experimental values (few measurements performed >30 years ago)
• Improvement of experimental facilities
Synchrotron, high resolution detectors, improved electronics
Improvement of calculation speed
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INTERNATIONAL INITIATIVE Goals
• Initiate new measurements taking advantage of technical improvements
•Perform similar measurements in different institutes to establish reliabilty and associated uncertainties of the experimental values
• Perform calculation for selected cases (use calculations for interpolations)
• Compare calculation to experiment
• Provide reliable practical tables to users
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INTERNATIONAL INITIATIVE Participants and events
• Active participation from :
3 National metrology institutes (LNHB-NIST-PTB)14 Research institutes10 Industrial companies
• 4 international workshops: 1st workshop Paris Oct. 2008 definition of expert groups
2nd workshop Berlin May 2009 road map generation
3rd workshop Paris Nov. 2010 project options
4th workshop NIST July 2011 definition of new expert groups
• New workshop: Berlin (Feb./Mar. 2013)
• Sessions at EXRS and DXC conferences
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INTERNATIONAL INITIATIVE Expert groups
1. Prioritization of FP requirements (energies, elements, uncertainties)
2. Experimental facilities (needs for improved instrumentation)
3. Theory & codes – challenges: competent use and update of software
4. Compilations (need for new strategies), data processing
5. Definition of technical terms ( NMIs: LNE, NIST and PTB )
6. Establishment of a common data base accessible to the public
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INTERNATIONAL INITIATIVE New possibilities
• Advantages of today’s facilities
• Use of monochromatic radiation (synchrotron) Tunable (primary enery close to the binding energy) Fine beam (collimation)
• Energy-dispersive detectors Energy resolution (Ka, Kb) Counting rates (up to 105 s-1)
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ATOMIC PARAMETERS
INTRODUCTION
INTERNATIONAL INITIATIVE
ATTENUATION COEFFICIENTS
FLUORESCENCE YIELDS (Ge)
PHOTON EMISSION INTENSITIES (241Am)
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Comparison of tables of mass attenuation coefficients
FP Initiative – compilation from group 4 (P. Caussin)
ATTENUATION COEFFICIENTSPresent status
Cullen vs. Elam
50% ≤ D < 100%
D ≥ 100%No Data
D < 1%1% ≤ D < 2% 2% ≤ D < 5%5% ≤ D < 10%
10% ≤ D < 20%20% ≤ D < 50%
Energy/keV
Z
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ATTENUATION COEFFICIENTSMonochromatic X-Ray sources
SOLEX: Monochromatic X-ray source in the 1-20 keV energy range
Vacuum chamber
X-ray tube (several anticathodes)
Dispersive crystal (different crystals)
Monochromatic beam in a constant direction
C. Bonnelle et al. Nuclear Instrum. Methods in Phys. Res. A 516, 594-601 (2004)
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ATTENUATION COEFFICIENTSMonochromatic X-Ray sources
SOLEIL: Synchrotron E=2.75 GeVCircumference : 354 m
Metrology beamline
2 beamlines“hard X-rays” 100 eV – 35 keV“XUV” 30 eV – 2 keV
With dedicated monochromating optics
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ATTENUATION COEFFICIENTSExperimental method
I=I0e-µx I0 I
x
Monochromatic radiation (E), normally incident on material with thickness x
µ : linear attenuation coefficient (cm-1)Reference flux I0
Transmitted flux I
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ATTENUATION COEFFICIENTSResults
I=I0exp(-µx))=I0exp(-µ/r.rx)Major difficulties: Beam quality and stability
Sample thickness: some tens of µm -> Uncertainties ?
Measurement of rx : mass (microbalance) / area (surface)
3.8 4.0 4.2 4.4 4.6
400
600
800
1000
1200
Energie/keV
/r
(cm
2 .g-1)
présente étude Données XCOM Chantler (1995) Nordfors (1961)
Tin mass attenuation coefficients
Cu (K edge at 8.98 keV)Relative uncertainty < 1 %
Sn (L edges at 3.93, 4.16 and 4.46 keV)
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ATOMIC PARAMETERS
INTRODUCTION
INTERNATIONAL INITIATIVE
ATTENUATION COEFFICIENTS
FLUORESCENCE YIELDS (Ge)
PHOTON EMISSION INTENSITIES (241Am)
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FLUORESCENCE YIELD OF GERMANIUM
Lack of reliable atomic data (FP initiative)
Germanium (Z=32)
Semiconductor industry
Nanotechnologies, solar energy
HPGe Detectors (Monte Carlo simulation)
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Tables of fluorescence yields for users
Krause (1979)
Bambynek (1984)
Hubbell (1994)
Elam (2002, see Hubbell)
Ratio between ωK values proposed by Hubbell et al. (1994) and those of Bambynek (1984)
See FP Initiative – compilation from group 4 (J.L. Campbell)
Ge FLUORESCENCE YIELD Present status - Tables
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Ge FLUORESCENCE YIELD Experimental values
0.51
0.52
0.53
0.54
0.55
0.56
0.57
0.58
Escape from gas with Ge
Radioactivity (As-74)
Fluorescenceusing Am-241
Fluorescence using Am-241
Fluorescence using Am-241
Germanium K Fluorescence Yield
Author (date) Methods Fluorescence yield UncertaintyPahor (1969) Escape from gas with Ge 0.570 0.003
Hartl (1976) Radioactivity (As-74) 0.561 0.015
Casnati (1984) Escape peak 0.549 0.011
Brunner (1987) Escape peak 0.532 0.016
Pious (1992) Fluorescence using Am-241 0.538 0.029
Durak (2001) Fluorescence using Am-241 0.537 0.030
Han (2007) Fluorescence using Am-241 0.552 0.040
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p : parent (incident energy)i : fluorescence energy (a=alpha, b=beta)
µ : Linear attenuation coefficient (cm-1)tK : Linear photoelectric absorption coefficient (cm-1)ei : Detector efficiency for energy i
FLUORESCENCE YIELD MEASUREMENT Conventional method – Reflection 1
xdx
I(Ep)a
Target
iiKppiddxxIdN e
t4
)*exp(
1: Transmission to depth x
2: Interaction by photoelectric effect in K shell
3 : Atomic rearrangement by X-ray emission (K)
4: Exit of the X-rays from the active volume
5: Interaction in detector (full-energy peak)
iiKiKpppidxdxxIdN eb
a
ta
4
)sin
exp(sin
)sin
exp(
b
a
sinsin* ipµ
b
dN(Xi)
Detector
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Requires accurate geometrical arrangementRequires accurate measurement of the primary radiation characteristics (reference detector)Knowlegde of the detector efficiency (including collimation geometry)Knowledge of the interaction cross sections
p : parent (incident energy)i : fluorescence energy (a=alpha, b=beta)
FLUORESCENCE YIELD MEASUREMENT Conventional method – Reflection 2
Target
I(E)a
N(X)a
0X XN dN
iKiKppi µlIN e
at
4*)*exp(1
sin1
)*exp(1*1sin4
lµ
IN
Kppi
iKi t
ae
iKiKppiddxxIdN ea
t4sin
)*exp(
Detector
Target
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Requires: Knowlegde of the detector efficiency (including collimation geometry)Knowledge of the interaction cross sections
p : parent (incident energy)i : fluorescence energy (a=alpha, b=beta)
FLUORESCENCE YIELD MEASUREMENT Conventional method - Transmission
iiipip
KpKipi ll
µµIN e
t
4)exp()(exp1
I(E)a
N(X)
a
Target
Detector
Mass attenuation coefficients in the range 3.8 < E < 11 keV, K fluorescence yield and Kb/Ka relative X-ray emission rate for Ti, V, Fe, Co, Ni, Cu and Zn measured with a tunable monochromatic X-ray source, Y. Ménesguen,, M.-C. Lépy, Nuclear Instruments and Methods in Physics Research B 268 (2010) 2477–2486
l
lµµN
Nip
ip
Kp
ip
P
P
i
iKi )(exp1
)(exp
t
ee
PppP lIN er4
)exp(
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HPGe detector = target
FLUORESCENCE YIELD MEASUREMENT Escape peaks method
The detector records the incident radiationFull-energy peak (Ep) -> Np
Escape peaks (Ep-EXKi) -> Ni
For Ge:EKa : 9.88 keVEKb : 10.98 keV Does not depend on the primary radiation nor detector efficiency
Requires interaction cross sections
I(E)a N(X)
Detector = target
1: Transmission to depth x
2: Interaction by photoelectric effect in K shell
3 : Atomic rearrangement by X-ray emission (K)
4: Exit of the X-rays from the active volume
)1ln(1
2 i
P
P
i
P
KiKi
baP
i
NNNN
t
(Axel, BNL report 271(1952))
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8 10 12 14 16 18 20 22 24 26-4
-2
0
2
4
6
Rel
ativ
e di
ffere
nce
(%)
Energy (keV)
Photoelectric absorption coefficients
Attenuation coefficients
Databases Hubbell (NIST/XCOM) Chantler (NIST/FFAST)
XCOM (direct)• Ka: 36.94 cm2.g-1
• Kb: 27.44 cm2.g-1
FFAST (interpolation)• Ka: 35.30 cm2.g-1
• Kb: 25.94 cm2.g-1
Comparison of FFAST & XCOM : The values in the FFAST dataset are calculated by different methods than the XCOM dataset and may produce different results. Disagreements in the total attenuation cross sections are generally less than 5 %, but can be larger in some cases, especially near absorption edges. Comparison with experimental data does not allow us to choose between the theoretical methods due to the scatter in the values of different experimental datasets.
FLUORESCENCE YIELD MEASUREMENT
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Experimental setup
• HPGe detector (thickness 4 mm – area 10 mm2)
• Monochromatic X-Ray source -> normal incidence SOLEX (LiF or Quartz monochromating crystal) (OS13-2)
3.5, 3.8 and 4.0 keV (L fluorescence), 12 to 16 keV
SOLEIL (Metrology beam line, hard X-ray branch – double Si monochromator) 12.2, 12.5, 12.7,13.0, 13.5, 14.0 keV
ESCAPE PEAKS EXPERIMENT
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X-Ray spectra
K fluorescence yield: incident energy > 12.2 keV
Ep = 1 4 k e V
En e rg y (k e V)
Co
un
ts p
er
ch
an
ne
l
1 6 11 1 6
1 0 0 0
6 0 0 0
1 0 0 0 0
Full-energy peak: E=14 keV
Escape peaks : E=3.02 and 4.12 keV
ESCAPE PEAKS EXPERIMENT
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Escape peaks processing
F i t o f e s c a p e p e a k Ep = 1 4 k e V
En e rg y (k e V)
Co
un
ts p
er
ch
an
ne
l
2 .1 2 .6 3 .1 3 .6 4 .1 4 .6
1 0 0
6 0 0
1 0 0 0
6 0 0 0
Peaks processing (peak area): COLEGRAM – Gaussian with left tail
)1ln(12
i
P
P
i
P
Ki
baP
iKi NNN
N
t
ESCAPE PEAKS EXPERIMENT
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Ge FLUORESCENCE YIELD Present results
FFAST: XCOM:
Ka = 0.479 (15) 0.483 (15)
Kb = 0.069 (2) 0.070 (2)
11 12 13 14 15 16 17 180.460
0.470
0.480
0.490
0.500
Ge Ka fluorescence yield
SOLEIL1
SOLEX - Quartz
SOLEX - LiF
SOLEIL2
Mean value
Energy of primary radiation/keV
Fluo
resc
ence
yie
d
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Ge FLUORESCENCE YIELD Synthesis
FFAST : Ge K = 0.548 (16)
XCOM: Ge K = 0.553 (17)
0.49
0.50
0.51
0.52
0.53
0.54
0.55
0.56
0.57
0.58
Bambynek
Krause
HubbellSchönfeld
Germanium K Fluorescence Yield
Experimental values
Compilations
Present result
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Ge K FLUORESCENCE YIELD
• Results with escape peaks : wK(Ge) 0.550 (15)
• Consistent with Bambynek database + calculations (Chen)
• L fluorescence yield : 0.016 (1)
• Next steps
Measurement of attenuation coefficients
Fluorescence of a target (transmission and reflection)
Comparison with new calculations (Univ. Libon)
Conclusion
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ATOMIC PARAMETERS
INTRODUCTION
INTERNATIONAL INITIATIVE
ATTENUATION COEFFICIENTS
FLUORESCENCE YIELDS (Ge)
PHOTON EMISSION INTENSITIES (241Am)
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Ge d e o n _ 2 4 1 Am_ 1 Ms .s p m
En e rg y (k e V)
Co
un
ts p
er
ch
an
ne
l
1 3 1 8 2 3
1 0 0
6 0 0
1 0 0 0
PHOTON EMISSION INTENSITIES241Am - Np L X-rays
Semiconductor detectors HPGe and Si(Li) (FWHM: 115 and 130 eV at 5.9 keV)Sources 241Am (electrodeposited and wheighted drops)Spectra processing using COLEGRAM
Ge d e o n _ 2 4 1 Am_ 1 Ms .s p m (1 5 .4 3 7 3 - 1 9 .1 4 2 9 )
En e rg y (k e V)C
ou
nts
pe
r c
ha
nn
el
1 5 .5 1 6 1 6 .5 1 7 1 7 .5 1 8 1 8 .5 1 9
1 0 0
6 0 0
1 0 0 0
Re s i d u a l s o f : Ge d e o n _ 2 4 1 Am_ 1 Ms .s p m (1 5 .4 3 7 3 - 1 9 .1 4 2 9 )
En e rg y (k e V)
Co
un
ts p
er
ch
an
ne
l
1 5 .5 1 6 1 6 .5 1 7 1 7 .5 1 8 1 8 .5 1 9
-5 0
0
241Am XL spectrum Region XLb
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PHOTON EMISSION INTENSITIES241Am - Np L X-rays
Identification Energy (keV)
Lorentzian width (eV)
Emission intensity
L alpha 2 13,76 0,01079 0,0138L alpha 1 13,95 0,01079 0,1188
L eta 15,86 0,02891 0,0038
Lbeta6 16,11 0,01909 0,0021Lbeta2,15 16,80 0,01159 0,0277
Lbeta4 17,06 0,029 0,0199Lbeta7 17,27 0,01 0,0018Lbeta5 17,51 0,01 0,0071Lbeta1 17,75 0,01 0,1238Lbeta3 17,99 0,01311 0,0139Lbeta10 18,58 0,022 0,0008Lbeta9 18,76 0,0172 0,0011
Lgamma 5 20,10 0,02141 0,0010Lgamma 1 20,79 0,01391 0,0324Lgamma 2 21,10 0,023 0,0053
Lgamma 8,3 21,30 0,012 0,0057Lgamma 6 21,49 0,021 0,0066Lgamma 4 22,12 0,012 0,0020Lgamma 13 22,40 0,015 0,0006
Identification and quantification of 19 components
ICRM2007Measurement of 241Am L X-ray emission probabilities, M.C. Lépy, J. Plagnard, L. Ferreux, Applied Radiation and Isotopes 66 (2008) 715–721
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PHOTON EMISSION INTENSITIESCryogenic detector
Thermal bath ~ 20 mK
Input coilPick-upcoil
B
SQUID
Au:Er Sensor
T0 ~ 20 mK
V
MetallicAbsorber
absorberPhotonEnergy
E
g
Temperatureincrease DT
sensor
Magnetizationchange DM
coils
Magnetic flux change DF
SQUIDVoltage or current change
Room temperature electronics
Amplificat
ion
Thermallink T = 300 K
DV
0 50 1000
0.1
0.2
Time (ms)
Vol
tage
(V)
time
Decay time td ~ ms Imposed by the thermal link
Few counts/s …(FWHM a td
-½)
0TCETMV DDDFD
Low temperature required T0 < 50 mK
Signal:
mT 5with
eV 5 ~~2
B
BgS B e )(4 02 TCTkB noise ThermalNoise:
At low temperature high energy resolution achievable
Statistical fluctuations negligible
Metallic Magnetic Calorimeters
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PHOTON EMISSION INTENSITIESCryogenic detector vs Semiconductor
Au-Ag absorber:DEFWHM = 37 eV @ 17.75 keVDEFWHM = 40 eV @ 60 keV Peak amplitude/background 7 times better:
• Better energy resolution • Smaller Compton background by a factor 2
HPGe:DEFWHM = 200 eV @ 17.75 keVDEFWHM = 340 eV @ 60 keV
Normalized on theLb1 amplitude
HPGe SMX1
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PHOTON EMISSION INTENSITIESSpectrum processing
Energy (keV)
Cou
nts
per c
hann
el
10.3 10.8 11.3 11.8 12.3 12.8 13.3 13.8 14.3 14.8
1000
6000
10000
s p e c tre _ 1 2 2 A_ 1 2 7 A_ 1 2 9 D_ HP1 _ L P3 k _ w_ b k g _ 2 .s p m (1 0 .2 1 8 7 - 1 5 .1 3 1 6 )
En e rg y (k e V)
Counts
per channel
1 3 .6 1 4 .1
1 0 0 0 0 0
6 0 0 0 0 0
1 e + 0 0 6
s p e c tre _ 1 22 A _ 1 2 7A_ 1 2 9 D_ HP1 _ L P3 k _ w_ b k g _ 2 .s p m (1 0 .2 1 8 7 - 15 .1 3 1 6 )
En e rg y (k e V)
Counts
per channel
11 . 3 11 .8
1 0 0 0 0
6 0 0 0 0
1 0 0 0 0 0 ? X
? X
g ?La2Ll
La1
Ll Np
La Pb
La Np
Ec. Ag
Lb1,2 Au Lb1 Pb
Lg1 AuLs
NpLg1 Pb
Lb1 Au
241AmNp L X-rays
Ll and La region
Unidentified peaks linked to rearrangement in L3 sub-shell
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SUMMARY
Presentation of LNHB studies using radionuclides and monochromatic tunable X-ray sources:
Intensive work on atomic parameters (International initiative on FP)
Improvement of mass attenuation coefficientsMeasurement of K and L fluorescence yields
Conventional work on photon emission intensities with new detectors (Cryogenic detector)
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Thank you for your attention!