measurement of atomic parameters at lnhb m arie -c hristine lépy and y ves ménesguen...

MEASUREMENT OF ATOMIC PARAMETERS

AT LNHB

Marie-Christine LÉPY and Yves MÉNESGUEN

LABORATOIRE NATIONAL HENRI BECQUEREL

FRANCE

DDEP MEETING – 08/10/2012 | PAGE 1

DDEP Meeting – 10/2012 LABORATOIRE NATIONAL HENRI BECQUEREL2

ATOMIC PARAMETERS

INTRODUCTION

INTERNATIONAL INITIATIVE

ATTENUATION COEFFICIENTS

FLUORESCENCE YIELDS (Ge)

PHOTON EMISSION INTENSITIES (241Am)


INTRODUCTION

Use of atomic parameters in decay data -> X-ray emission intensities

Fluorescence yields

Relative intensitiesKb/Ka, Ka2/Ka1, etc.


X-RAY DATA

55Fe decays by electron capture

Example : 55Fe

𝑈 𝑅(𝐼 𝑋𝐾 )=√𝑈 𝑅❑2 (𝑃𝐾 )+𝑈 𝑅

❑2(𝜔𝐾)


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



International initiative on x-ray fundamental parameters

Launched in 2008 (EXRS conference)


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


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


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


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


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)


ATOMIC PARAMETERS

INTRODUCTION






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


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)


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


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


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)


ATOMIC PARAMETERS

INTRODUCTION






FLUORESCENCE YIELD OF GERMANIUM

Lack of reliable atomic data (FP initiative)

Germanium (Z=32)

Semiconductor industry

Nanotechnologies, solar energy

HPGe Detectors (Monte Carlo simulation)


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


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


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


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


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


Requires: Knowlegde of the detector efficiency (including collimation geometry)Knowledge of the interaction cross sections


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(


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))


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


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


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 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



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


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


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


ATOMIC PARAMETERS

INTRODUCTION






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


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


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


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


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


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)


Thank you for your attention!

measurement of atomic parameters at lnhb m arie -c hristine lépy and y ves ménesguen...

Documents

tables of bambynek

new table

atomic number

hubbell data

experimental results

elam table

relative difference

small number of new