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

08.09.2017 2

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

08.09.2017 3

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)

08.09.2017 4

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

08.09.2017 5

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

08.09.2017 8

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

08.09.2017 16

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

08.09.2017 21

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

08.09.2017 22

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

08.09.2017 Grainau meeting 24

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

08.09.2017 Grainau meeting 26

• 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

08.09.2017 Grainau meeting 27

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).

08.09.2017 Grainau meeting 28

Thank you