SLIDE 1
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
Practical Approaches using TDCR Measurements and Alpha/Beta - - PowerPoint PPT Presentation
Practical Approaches using TDCR Measurements and Alpha/Beta - - PowerPoint PPT Presentation
PAUL SCHERRER INSTITUT Practical Approaches using TDCR Measurements and Alpha/Beta Separation Jost Eikenberg, Maya Jggi, Andreas Brand Division for Radiation Protection and Safety Paul Scherrer Institute, CH-5232 Villigen Paul Scherrer
SLIDE 2
SLIDE 3
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
Overview / Topics
- TDCR standardization measurements with
typical isotopes from the nuclear fuel cycle
- Presentation of a radiochemical method for
simultaneous determination of 210Pb and
226Ra+228Ra
- Simultaneous determination of 241Pu (β-emitter)
and 238Pu, 239Pu+240Pu (α-emitter) in nuclear materials
SLIDE 4
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
TDCR standardization measurements
- LSC measurements using pure β-emitting
isotopes: 3H, 63Ni, 14C, 36Cl and 90Sr/90Y (isotopes in the order of increasing β-energy)
- Presentation of unquenched vs. quenched data
SLIDE 5
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
TDCR vs. Efficiency: all isotopes
TDCR vs Efficiency: all nuclides, unquenched data
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0.100 0.200 0.300 0.400 0.500 0.600 0.700 0.800 0.900 1.000
- rel. efficiency
- rel. TDCR
SLIDE 6
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
Tritium: 3H (Emax: 18.6 keV)
TDCR vs Efficiency: H-3
0.1 0.2 0.3 0.4 0.5 0.000 0.100 0.200 0.300 0.400 0.500
- rel. efficiency
- rel. TDCR
SLIDE 7
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
63Ni (Emax: 65.9 keV)
TDCR vs Efficiency: Ni-63
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0.100 0.200 0.300 0.400 0.500 0.600 0.700 0.800 0.900 1.000
- rel. efficiency
- rel. TDCR
SLIDE 8
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
Radiocarbon: 14C (Emax: 156 keV)
TDCR vs Efficiency: C-14
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0.100 0.200 0.300 0.400 0.500 0.600 0.700 0.800 0.900 1.000
- rel. efficiency
- rel. TDCR
SLIDE 9
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
36Cl: (Emax: 709 keV)
TDCR vs Efficiency: Cl-36
0.5 0.6 0.7 0.8 0.9 1 0.500 0.600 0.700 0.800 0.900 1.000
- rel. efficiency
- rel. TDCR
SLIDE 10
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
90Sr/90Y (Emax: 546/2280 keV)
TDCR vs Efficiency: Sr-90
0.5 0.6 0.7 0.8 0.9 1 0.500 0.600 0.700 0.800 0.900 1.000
- rel. efficiency
- rel. TDCR
SLIDE 11
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
Environmental application: determination of 228Ra, 226Ra and
210Pb in aqueous samples using
TDCR measurement technique and α/β-separation
SLIDE 12
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
238U 234U 230Th 234Pa 234Th 226Ra 222Rn 218Po 214Po 210Po 210Bi 210Pb 206Pb 235U 231Pa 231Th 227Th 227Ac 223Ra 219Rn 232Th 228Th 228Ac 224Ra 228Ra 220Rn 215Po 211Pb 207Pb 211Bi 212Bi 216Po 212Po 212Pb 208Pb 207Tl 208Tl 214Bi 214Pb
4.47x109y 2.45x105y 24.1d 7.54x104y 1.17min
α 4.196 MeV α 4.776 MeV α 4.688 MeV α 4.784 MeV α 5.490 MeV α 6.003 MeV
1600y 3.825d 3.11min 19.9min 26.8min 22.3y 7.04x108y
α 6.038 MeV α 4.395 MeV β α 5.013 MeV
3.28x104y
β
18.7d 21.8y 11.4d
α 4.010 MeV
1.41x1010y 1.91y 5.75y
α 5.423 MeV
6.13h
β
3.66d
α 5.686 MeV
55.6s
α 6.288 MeV β β β β
1.6x10-4s 5.01d
α 7.687 MeV α 5.304 MeV
stable 138.4d
β β
1.06d
β α 5.716 MeV α 6.819 MeV
3.96s 1.8x10-3s 2.14min 36.1min stable
α 7.386 MeV α 6.623 MeV
4.77min
β
66.3% 0.15s
β β α 6.779 MeV
1.01h 33.7%
α 6.051 MeV
10.6h 3.05min
β
stable
β α 8.784 MeV
3x10-7s
238U-Series 235U-Series 232Th-Series
U Pa Th Ac Ra Fr Rn At Po Bi Pb Tl
SLIDE 13
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
Th-Ra relationship in the 232Th and
238U decay series
230 7 54 10 226 160 10 222 382 218
4 3
Th Ra Rn Po daughters
a a d α α α : . : . : . ⋅ ⋅
→ → → +
232 140 10 228 5 76 10 228 613 228
10
Th Ra Ac Th daugthers
a a h α β β : . : . : . ⋅ ⋅
→ → → +
228 19110 224 3 66 220 55 6 216
Th Ra Rn Po daugthers
a d s α β α : . : . : . ⋅
→ → → +
SLIDE 14
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
Continental water: relevant isotopes
- Alpha-emitter: U-238, U-234
- Beta-emitter: Ra-228 (with fast ingrowing Ac-228)
- Alpha-emitter: Ra-226 (with Rn-222 prognies)
- Beta-emitter: Pb-210 (with ingrowing Bi-210)
- Alpha-emitter: Po-210
SLIDE 15
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
Schematic view of radioactive transformation
α
1 (95.5 %)
γ1
Z = 88 Z = 86
222Rn (3.82 d)
α
2 (4.5 %)
0.0 0.0 0.186
226Ra (1600 y)
88 226 86 222 2 4
4 78 Ra Rn He MeV → + + .
SLIDE 16
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
relevant isotopes in continental water and their measurement methods at PSI
radionuclide analytical technique
234U, (235U), 238U
U/TEVA separation, electro- deposition, α-spectrometry
226Ra, 228Ra, 210Pb
filtration (RadDisc), OptiPhase Hisafe3 cocktail, LSC
210Po
spontaneous deposition on silver disc, α-spectrometry
SLIDE 17
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
Relationship parent / daughter
parent isotope half-life parent ingrowing daughter half-life daughter
210Pb (β)
22.3 years
210Bi (β)
6.02 days
226Ra (α)
1602 years
222Rn (α)
3.82 days
228Ra (β)
5.76 years
228Ac (β)
6.13 hours
SLIDE 18
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
Method implementation: low level determination
- f 210Pb, 226Ra+228Ra in drinking water
- Filtration of the sample (2 liter) through 3 Empore
RadDisc (Mn-oxide impregnated) membrane filters
- Elution of Pb with Diammonium Hydrogen Citrate
- Elution of Ra with alkaline Na-EDTA solution
- Measuring via LSC with optimized α/β-
discrimination
SLIDE 19
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
Classical two photomultiplier LS electronic set-up
SLIDE 20
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
Pulse shape α/β discrimination
20 40 60 80 100 120 140 160 200 400 600 800 1000 1200
alpha-pulse beta-pulse
relative intensity pulse decay time [ns]
SLIDE 21
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
Spill-over α/β determination
100 110 120 130 140 150 2 4 6 8 10 12 14
β in α α in β
spillover [%] discriminator setting [ns]
SLIDE 22
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
The triple coincidence to double coincidence ratio (TDCR) counting technique
SAM PLE PM R
PM S
PM T
SLIDE 23
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
Pulse Length Index (PLI) discrimination with HIDEX SL 300
27 38 52 72 99 135 185 252 343 466 634 861 1169 1588 2156 2927 3973 5393 7319 9934 13481 18296 4 8 12 16 20 24 28
SLIDE 24
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
α-spectrum of 226Ra with ingrowing daughters 2 h and 8 h after separation using HIDEX 300 SL LSC
Alpha
20 40 60 80 100 120 140 10 100 1000 10000
SLIDE 25
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
α-spectrum of 226Ra with ingrowing daughters
- btained 6 days after separation
Alpha
20 40 60 80 100 120 140 160 10 100 1000 10000
SLIDE 26
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
β-spectrum of 214Bi/214Pb obtained 6 days after separation (226Ra/222Rn decay series products)
Beta
5 10 15 20 25 30 35 1 10 100 1000
SLIDE 27
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
β-spectrum of 228Ra with ingrowing 228Ac 1 h and 8 h after separation using HIDEX 300 SL LSC
Beta
5 10 15 20 25 30 35 40 45 50 1 10 100 1000
SLIDE 28
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
TDCR vs. Efficiency using high purity radionuclide standard solutions
0.4 0.5 0.6 0.7 0.8 0.9 1.0 0.4 0.5 0.6 0.7 0.8 0.9 1.0
TDCR = efficiency
226Ra 210Pb 228Ra
TDCR efficiency
SLIDE 29
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
long lived mother – short lived daughter relationship
A t A e e A e
y x y y x xt yt y yt
( ) ( ) ( ) ( ) = ⋅ − ⋅ − + ⋅
− − −
λ λ λ
λ λ λ
A t A e e
y x y y x xt yt
( ) ( ) ( ) = ⋅ − ⋅ −
− −
λ λ λ
λ λ
λ λ λ λ λ
x y y y x
<< ⇒ − → 1
) 1 ( ) ( ) (
t x y
y
e A t A
λ −
− ⋅ =
SLIDE 30
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
LS-spectrum interference correction
228 228 − −
=
Ac B A Ac
R ε ε
) ( ) (
228 228 , 228 ,
Ac r R r Ra r
B n Ac A m n A cor n
⋅ − =
−
A Ra cor n Ra
Ra r A
228 228 , 228
) (
− −
= ε
B Ac B n Ac
Ac r A
228 228 228
) (
− −
= ε
SLIDE 31
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
Comparison of measured 228Ra and 228Ac activities with calculated decay/ingrowth curves
10 20 30 40 50 60 70 80 0.0 0.5 1.0 1.5 2.0 2.5
228Ac: measured data 228Ra decay curve 228Ra: measured data 228Ac ingrowth curve
relative activity time after separation [h]
SLIDE 32
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
Comparison of measured 226Ra and the progeny isotopes
222Rn, 218Po and 214Po with calculated decay/ingrowth curves
5 10 15 20 25 30 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
222Rn+ 218Po+ 214Po: measured data 226Ra decay curve 226Ra: measured data 222Rn+ 218Po+ 214Po ingrowth curve
relative activity time after separation [d]
SLIDE 33
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
Comparison of measured 210Pb and 210Bi activities with calculated decay/ingrowth curves
2 4 6 8 10 12 14 0.0 0.2 0.4 0.6 0.8 1.0
210Bi: measured data 210Pb decay curve 210Pb: measured data 210Bi ingrowth curve
relative activity time after separation [d]
SLIDE 34
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
Minimizing the interferences: 210Pb
- 210Pb: start counting not before 3 hours
after separation because 226Ra unsupported progeny products (i.e. 214Pb/214Po) have to decay prior to the measurement (β- spectrum interferences)
SLIDE 35
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
Minimizing the interferences: 226Ra
- 226Ra: 224Ra [(t1/2) = 3.66 days] and its short
lived progeny products should have been decayed prior to measurement, i.e. the sampled water should set aside for about 10 days before radiochemical separation (support from 228Th has to be checked !). The same holds for 210Pb (interference with 10 h half live decaying pure β-decaying 212Pb)
SLIDE 36
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
Minimizing the interferences: 228Ra
- The samples should be measured during the first
24 hours after chemical separation, i.e. when the ingrowth of the 226Ra/222Rn couple decay products (i.e. 214Pb, 214Bi) is not of large
- concern. These isotopes interfere strongly with
the β-spectrum of 228Ac, which has to be taken to correct the low energy spectrum of 228Ra
SLIDE 37
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
m s
t r V k A
1 *
2 1 ⋅ ⋅ ⋅ ⋅ =
−
ε
α
5 10 15 20 25 10 20 30 40 50
226Ra 228Ra 210Pb
lower limit of detection [mBq / L] counting time [h]
SLIDE 38
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
LSC detection limits, 2 l aliquot, quantitative adsorption on RadDisc filter, counting time 6 h
- Ra-226: 3 mBq/liter
- Ra-228: 20 mBq/liter
- Pb-210: 15 mBq/liter
SLIDE 39
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
Field study: use of Ra-isotopes as natural tracers: isotopic signatures for determining mixing between waters from different source regions
I l l Belfort Mulhouse Basel
JURA
Aare Zürich Stuttgart Strasbourg Séléstat Colmar Rhine Nancy R h i n e
N
BLACK FOREST VOSGES
France
SLIDE 40
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
Calculating mixing/exchange between river and ground water using 228Ra/226Ra and 87Sr/86Sr
0.0 0.5 1.0 1.5 2.0 2.5 0.705 0.710 0.715 0.720 0.725 0.730
30 27/1 27/2 24 19 18
river Rhine Rhine Valley groundwater Strengbach river (pure granitic)
- ther Vosges rivers (mainly granitic)
river Ill and tributaries 87Sr/ 86Sr (atomic ratio) 228Ra/ 226Ra (activity ratio)
SLIDE 41
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
TDCR blank correction
2 2 1 1
M C M C M C
m m
⋅ + ⋅ = ⋅
0 TDCR
r TDCR r TDCR r
n n b b
⋅ + ⋅ = ⋅
For linear systems the general mass balance equation holds for mixtures of two components M1 and M2 with the concentrations C1 und C2 This relationship can be directly transferred to TDCR-measurements, i.e. the „true“ or net-TDCR (TDCRn) value has to be obtained via the brut-TDCR („mixture“) (TDCRb) and the TDCR-result of a blanc measurement (TDCR0) . with
r r r
b n
− =
( )
TDCR r TDCR r r TDCR r
n b b b
⋅ + ⋅ − = ⋅
r r TDCR r TDCR r TDCR
b b b n
− ⋅ − ⋅ =
n n
TDCR ε ≈
n b n n
r r r A ε ε − = =
( )
b b b b
TDCR r TDCR r r r A ⋅ − ⋅ − =
2
It follows: For pure β-emitter holds: with: It results for the activity calculation
SLIDE 42
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
Simultaneous determination of 241Pu (β- emitter) and 238Pu, 239Pu+240Pu (α- emitter) in nuclear materials
- Application of extraction chromatography: adsorption onto
BioRad 1X2 anion exchange resin
- Elution of the Pu-fraction using a HI/HCl acidic reduction
solution
- Electrodeposition onto a stainless steel planchet, α-
spectrometric measurement
- Dissolution from the sample planchet, cocktail preparation
- α/β-measurement via LSC
SLIDE 43
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
241Am
α 433 a 5.5 MeV
243Am
α 7370 a 5.3 MeV
236Pu
α 2.8 a 5.8 MeV
238Pu
α 88 a 5.5 MeV
239Pu
α
2.4 104a
5.2 MeV
240Pu
α 6550 a 5.2 MeV
241Pu
β 14.4 a 0.021 MeV
242Pu
α
3.7 105 a
4.9 MeV
SLIDE 44
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
Actinide analysis: 1-X2 / DGA separation
Uranium
NO2- + 2H+ + e- = NO + H2O Pu3+ = Pu4+ + e- 2 M HNO3 discard 0.25 M HNO3
Americium, Curium
DGA resin
U, Am, Cm
5 M HCl
+ ascorbic acid [Fe2+] + Na-nitrite: [Pu4+] + yield spike isotopes
0.2 M HCl
+ 3 MHNO3
3 M HNO3
Plutonium Thorium
0.01 M HI + 9 M HCl
9 M HCl
1-X2 resin
sample solution
SLIDE 45
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
redox reactions and equilibria
reduction of Pu(vi) to Pu(iii)
_______________________________________________________
− −
+ ↑ → e I I 2 2
2
+ − +
→ +
3 4
2 2 2 Pu e Pu
+ + −
+ ↑ → +
3 2 4
2 2 2 Pu I Pu I
SLIDE 46
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
α-spectrum of U, Pu and Am (blue sample isotopes to be analyzed; red added spike isotopes)
4.0 4.5 5.0 5.5 6.0 100 200 300 400
236Pu 234U 236U 238U 243Am 239Pu 241Am
α-Energie [MeV] Impulse/Kanal
SLIDE 47
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
a/b-LSC with optimized α/β separation (pulse index and energy), α-spill in β < 1%, β-spill in α < 0.1%
241Pu β 238, 239, 240, 242Pu
α
SLIDE 48
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT
Conclusions
- TDCR measurement of non or weakly quenched samples
yield sufficiently precise results for radionuclide analysis in the frame of decommissioning projects.
- Environmental application: LSC with optimized alpha/beta
separation is a powerful tool to determine almost pure α- emitting 226Ra besides weak β-emitting 228Ra
- Determination of Pu-isotopes in materials from the nuclear
fuel cycle: optimized α/β-separation yields precise results for measurement of pure beta emitting 241Pu
SLIDE 49
Paul Scherrer Institut • 5232 Villigen PSI LSC Int. Conference, Copenhagen, 01-05.05.2017
PAUL SCHERRER INSTITUT