UPDATING THE SPECTROSCOPY DATA LIBRARY FOR PGAA · UPDATING THE SPECTROSCOPY DATA LIBRARY FOR PGAA...
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UPDATING THE
SPECTROSCOPY DATA
LIBRARY FOR PGAA
Zs. Révay, Ch. Stieghorst, P. Kudejova,
K. Kleszcz Technical University Munich, Research Neutron Source
Heinz Maier-Leibnitz, Garching, Germany
Comparison of activation analyses
Prompt gamma activation analysis
After the capture of one neutron. 6—8 MeV is released typically in hundreds
of transitions
A large fraction of the spectrum is Compton plateau, or unresolveable peaks
(instrumental) neutron activation analytsis
1—2 MeV is released in a few (dozens) of transitions
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0 1000 2000 3000 4000 5000 6000
Energia (keV)
No
rmá
lt b
eü
tés
szá
m .
Eu
Gd
Dy
Os
Ir
1200
1300
1400
1500
1600
1700
1800
1200 1250 1300 1350 1400 1450 1500
Energia (keV)
Be
üté
sszá
m . .
Activation in PGAA
■ How do we activate in (in-beam) PGAA?
■ Cold neutron beams
■ Beam geometry
■ Self-shielding calculations is simpler in parallel beams
■ Can be calculated iteratively from composition
■ Cold neutron beams
■ Every nuclide follows 1/v law
■ No epithermal activation
■ No fast activation
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1.E-05
1.E-04
1.E-03
1.E-02
1.E-01
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05
1.E-05 1.E-03 1.E-01 1.E+01 1.E+03 1.E+05 1.E+07
Energy (eV)
Neut
ron
capt
ure
cros
s se
ctio
n (b
arn)
H
Cl
Cd
cos sincos sin
0 0
1
cos sin
n
nd
d x
n
I ee dx
I
Detection in PGAA
■ What do we see in PGAA?
■ Prompt gamma lines
■ Quasi-prompt gamma lines (short-lived decay gamma lines)
■ Decay gamma lines – depending on the count rate of the sample
■ (Typical count rate 1000—10 000 cps)
■ Self-absorption
■ From the composition iteratively
■ Large sample-to-detector distances (15—35 cm)
■ Collimated detector
■ No true coincidence summing problem
■ (Random coinc summing can be a problem at high count rates)
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cos sincos sin
0 0
1
cos sin
n
nd
d x
n
I ee dx
I
Time dynamics in PGAA
■ Typically no decay correction
■ If yes, in-beam decay correction factor:
■ Any systematic error from that is negligible
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11
teB
t
0 1 2 3 4 5 *t
re
l. n
um
be
r o
f co
un
ts
prompt
decay
shifted prompt
c
ttt
t
eCeDeS
c
dirr
1
1
Formulation (nuclear constant approach)
■ Decay correction vanishes
■ Epithermal correction vanishes
f
QP
M
Nm
CDSt
A
f
QP
M
Nm
CDSt
A
sACd
sA
00
00
)(
1
Formulation
00
PM
Nm
t
A A
σγ
c
x
x
cc
M
Mxk
,
,
,0 )(
■ Mc=1.0079, σγ=0.3326 ± 0.2%
Formulation (spectroscopy approach)
■ In NAA
■ In PGAA
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cCdc
xCdx
c
CDStm
A
CDStm
A
CDStm
A
CDStm
A
xk
,
,
,0 )(
, , ,
0,
, , ,
/ ( )( )
/ ( )
x x c x cc
c c c c x
A m E Mk x
A m E M
2,
1,
2
1
22
11
/
/
n
n
A
A
Facilities at MLZ, Garching
Collimator and elliptical guide interchangeable New revised version of
the guide support
At focal point:
6×1010 cm-2 s-1
Other facilities
~108 cm-2 s-1
Collimated:
2×109 cm-2 s-1
Area:
2 x 2 cm2
Area:
1.5 x 1 cm2
5.8 m elliptical guide
1.1 m elliptical extension (removeable)
PGAA instrument at Garching
Compton-suppressed detector and digital electronics
Max. rate = ~ 50,000 cps
Compton suppression
160
30
19
BUDAPEST COMPTON-SUPPRESSED / PAIR-MODE GAMMA SPECTROMETER
8 x BGO
PM
PM
PM
PM
HPGe200
366
BGOcatcher
180
65,5
PM
6Li-containing plastic (2.5 mm)
Sn sheets (4 mm) – instead of Cd
10 cm of lead
5mm boron rubber (40% B4C)
5cm boron plastic (20% H3BO3)
Low-background chamber next to neutron guides
Efficiencies
PGAA detector NAA detector
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Earlier PGAA databases
■ 1969-70: MIT (Rasmussen-Orphan) ■ 75 elements measured with Ge(Li)
■ 1981: Lone table (Chalk River) ■ Compilation of mainly Rasmussen’s data
■ 1993: IAEA – Lone table as an attachment to a report
■ 1995: Tuli database (Alfassi’s PGAA book) ■ ENSDF data for nuclides, where available
■ The rest is Lone table (Z<20)
■ Only energies and relative intensities
k0 or σγ databases for in-beam activation
■ PGAA
■ Analysis of spectra of elements, oxides, stoichiometric compounds,
homogeneous mixtures (water solutions!)
■ NAA – short-lived nuclides
■ From prompt gamma spectra
■ Chopped-beam measurement
■ In-beam activation + passive counting
Cold PGAA library
■ 6200 lines used for
chemical analysis
■ Mainly measured 1997-
2001
■ Minor updates since then
■ Budapest (L. Szentmiklósi)
■ Garching (Zs.R.)
Z El A M W # E dE d % RI Area cps/g
1 H 1 1.01 1 2223.259 0.019 0.3326 0.2 100.00 100.00 64.183
1 H 2 1.01 2 6250.204 0.098 0.000492 5.0 0.15 5.00 0.0286
3 Li 6 6.94 5 477.586 0.050 0.001399 5.9 3.52 10.14 0.1218
3 Li 7 6.94 2 980.559 0.046 0.004365 5.1 10.97 18.74 0.2251
3 Li 7 6.94 3 1051.817 0.048 0.004364 5.1 10.97 17.83 0.2141
3 Li 7 6.94 1 2032.310 0.070 0.0398 5.0 100.00 100.00 1.2007
3 Li 6 6.94 6 6769.633 0.263 0.001354 6.5 3.40 0.84 0.0101
3 Li 6 6.94 4 7246.800 0.275 0.002106 8.4 5.29 1.17 0.014
4 Be 9 9.01 4 853.631 0.011 0.00165 8.9 26.69 100.00 0.0723
4 Be 9 9.01 3 2590.014 0.025 0.00188 8.9 30.41 49.08 0.0355
4 Be 9 9.01 2 3367.484 0.035 0.002924 8.9 47.30 58.96 0.0427
4 Be 9 9.01 5 3443.421 0.036 0.000993 8.9 16.06 19.54 0.0141
4 Be 9 9.01 6 5956.602 0.092 0.000146 9.1 2.36 1.41 0.001
4 Be 9 9.01 1 6809.579 0.099 0.006181 9.0 100.00 48.52 0.0351
5 B 10 10.81 1 477.600 5.000 712.5 0.3 100.00 100.00 39806
6 C 12 12.01 2 1261.708 0.057 0.00123 2.7 45.58 100.00 0.0306
6 C 12 12.01 3 3684.016 0.069 0.001175 3.5 43.53 38.02 0.0116
6 C 12 12.01 1 4945.302 0.066 0.002699 2.9 100.00 60.55 0.0186
7 N 14 14.01 22 583.567 0.031 0.000429 3.3 1.81 6.93 0.0159
7 N 14 14.01 12 1678.244 0.029 0.006254 1.5 26.34 47.15 0.1085
7 N 14 14.01 18 1681.174 0.043 0.001296 2.7 5.46 9.76 0.0225
7 N 14 14.01 21 1853.944 0.052 0.000474 4.5 2.00 3.31 0.0076
7 N 14 14.01 5 1884.853 0.031 0.0145 1.3 61.07 100.00 0.2301
7 N 14 14.01 24 1988.532 0.077 0.000294 5.8 1.24 1.94 0.0045
7 N 14 14.01 15 1999.693 0.032 0.003208 1.7 13.51 21.12 0.0486
7 N 14 14.01 13 2520.446 0.039 0.004246 1.8 17.88 22.98 0.0529
Library measurements
■ Elemental spectra: to obtain ...
■ Relative positions
■ Relative intensities
■ Energy calibration: to absolutize energy scale
■ 2 energies det-d for the 2-point E-calibration
■ Non-linearity correction
■ Standardization: to absolutize intensity scale
■ efficiency ratios
■ Only compounds
■ One- or two-step standardization ■ C, N, O, F, S, Cl, Fe (Au)
■ Ultimate comparator: H: 2223.255 keV 0.3326(7) barn
■ Low-energy part with LEGe detector
■ Better resolution between 10 keV– 1MeV
■ Decay measurements
■ Make a link to k0 database
ECl1 ECl2 ECl3 ECl4 E1 E2
, ,
( )
( )
c x xx c
x c c
n A E
n A E
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Selected updated values
El Energy
(keV)
Old σγ (barn) New σγ (barn)
Be 853.6 0.00208(24) 0.00195(5)
2590.0 0.00191(15) 0.00213(4)
3367.4 0.00285(22) 0.00275(7)
3443.4 0.00098(7) 0.00092(4)
6809.6 0.0058(5) 0.00506(13)
O 870.7 0.000177(11) 0.000168(6)
1087.7 0.000158(7) 0.000140(4)
Cr 834.8 1.38(3) 1.340(20)
8884.4 0.78(5) 0.7684(18)
Co 277.2 6.77(8) 6.044(10)
556.0 5.76(6) 5.15(9)
6877.2 3.02(6) 2.66(4)
Ni 465.0 0.843(10) 0.872(6)
8998.4 1.49(15) 1.45(3)
El Energy
(keV)
Old σγ (barn) New σγ (barn)
Ta 270 2.60(6) 4.49(10)
402 1.180(23) 1.97(20)
W 5261 0.86(4) 0.46(2)
Re 316.5 2.21(10) 2.11(4)
390.9 1.15(5) 1.28(4)
Hg 367.9 251(5) 213(8)
Ce 662.0 0.241(15) 0.466(8)
Pr 176.8 1.06(4) 1.184(25)
Nd 696.5 33.3(23) 39.0(12)
Sm 334.0 4790(60) 2160(90)
Eu 221.3 73(3) 148(5)
Gd 181.9 7200(300) 6700(400)
Conclusions and future plans ■ Most important elements are OK, unc-s may be underestimated though
■ Systematic errors due to
■ Self-attenuation (both n and γ)
■ Interference problems
■ Inhomogeneities
■ Water solution or lattic water thermalized the cold neutrons
■ All stable elements, thin samples
■ Also with low-energy germanium detector
■ Energy calibration with chlorine (PVC)
■ Standardization with several peaks on thin samples
■ More stoichiometric compounds
■ Chlorides
■ H-containing compounds
■ Water solutions
■ Noble gases: gas mixtures
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User statistics: PGAA and in-beam AA
• Archeology
• D/H rate in deuterated samples
• B in different matrices
• H in difefernt matrices
• Air filters, other environmental
• Nuclear data measurements
• Nuclear physics
• High-flux irradiation
Overbooking factor around 2
Applications
Recent applications
Composition of super-alloys
B with PGAA
Co, Re, Cr, Ta with PGAA and NAA
B content of zeolites (PGAA)
Trace elements in carbons H, B, N, Mn: 0.1-10ppm
Cl content of iron objects PGAA (20-1000ppm)
Composition of meteorites with PGAA and NAA
B (~10ppb) and H (~ppm) in high-purity Si (PGAA and NAA), Zr, Mg
H (ppm) in zircaloy (PGAA)
H in Mg
Irradiation of radioactive nuclides (actinides)
Passive counting, PGAA and NAA
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Typical sample: many major and minor components
Micro-meteorites
Mass ~0.3—2mg
In 0.5μm Mylar (PET) foil
No Teflon string
R.B. Firestone
Z El Mm
meas
unc
%
m
Bkg
unc
%
m
net
ox.
st.
m
ox
unc
%
1 H 1.008 5.47E-6 0.8 1.36E-6 1.5 4.11E-6 1 3.67E-5 1.2
5 B 10.81 6.74E-7 0.3 1.15E-8 1.0 6.63E-7 3 2.13E-6 0.3
13 Al 26.98 4.51E-5 2.2 1.96E-5 2.5 2.55E-5 3 4.82E-5 4.
14 Si 28.09 9.22E-5 2.8 1.96E-5 3.7 7.26E-5 4 1.55E-4 3.7
16 S 32.07 4.67E-6 14. 0.0 4.67E-6 6 1.17E-5 14.
17 Cl 35.45 1.09E-6 18. 1.15E-7 22. 9.71E-7 -1 9.71E-7 20.
20 Ca 40.08 2.10E-5 19. 0.0 2.10E-5 2 2.94E-5 19.
22 Ti 47.87 2.45E-4 2.6 1.40E-7 22. 2.45E-4 4 4.09E-4 2.6
24 Cr 52 4.03E-6 14. 0.0 4.03E-6 3 5.89E-6 14.
25 Mn 54.94 8.75E-6 2.0 0.0 8.75E-6 3 1.26E-5 2.0
26 Fe 55.85 2.31E-4 2.4 1.16E-6 10. 2.30E-4 3 3.28E-4 2.4
27 Co 58.93 3.06E-6 3.1 0.0 3.06E-6 2 3.89E-6 3.1
60 Nd 144.2 8.89E-7 13. 0.0 8.89E-7 3 1.04E-6 13.
62 Sm 150.4 5.32E-8 6. 0.0 5.32E-8 3 6.16E-8 6.
64 Gd 157.3 9.89E-8 7. 0.0 9.89E-8 3 1.14E-7 7.
1 mg
About 12,900 years ago Mammoths and other megafauna
became extinct
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• Mammoths and megafauna disappeared
• Smaller mammal populations declined
• Clovis people disappeared
• North America turned 10ºC colder
• Massive burning occurred
• Black mat covers the landscape
Wittke et al PNAS 109 (2012) E2088
Bunch et al PNAS 109 (2012) E1903
?
R.B. Firestone
Archaemetry
See further details in Christian Stieghorst’s talk (Wed 11:00 MatSci)
Chlorine in iron objects
Slow down the corrosion of artifacts
Understand the corrosion of iron
Britta Schmutzler, Friedrich Wagner
Carbonate layers in aqueducts
Trace elements
Cornelius Passchier
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Nuclear physics
Investigation of nuclear level schemes using (n,γ)
reaction
Coincidence measurements for two-step gamma
cascade
Level density and relative strength function
threshold for breaking Cooper pairs has a higher value for
spherical nuclei than for deformed ones
Our relative peak intensities help to check models
describing nuclei level densities in the continuum region
Statistical model using probability density functions
”DiceBox” calculation, ~Monte Carlo for deexcitation
In search for dark matter (X boson 16.7 MeV ??)
Attila Krasznahorkay, Debrecen
Anomalous angular correlation on 8Be
Now γ γ decay on 3He(n, γ)4He
Krasznahorkay et al., Phys. Rev. Lett. 116, 042501 (2016).
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Thank you