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Complex Dose Rate Calculations in Luminescence Dating of Lacustrine and Palustrine Sediments from Niederweningen, Northern Switzerland

Frank Preusser
Frank Preusser
, 
Detlev Degering
Detlev Degering
, 
Alexander Fülling
Alexander Fülling
 oraz 
Johannes Miocic
Johannes Miocic
   | 16 lis 2023
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Data publikacji: 16 lis 2023
Zakres stron: 28 - 49
Otrzymano: 27 mar 2023
Przyjęty: 23 sie 2023
DOI: https://doi.org/10.2478/geochr-2023-0003
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© 2023 Frank Preusser et al., published by Sciendo
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Fig 1.

(A) – Map indicating the location of the study area in the Swiss Alpine foreland with the extent of the LGM ice cover (blue-green) and overdeepened structures below the present day land surface (grey). (B) – Detailed map of the Wehntal with the location of previous (white circles) and present (black circles) sites investigated in the village of Niederweningen (modified after Dehnert et al., 2012). LGM, last glaciation maximum.
(A) – Map indicating the location of the study area in the Swiss Alpine foreland with the extent of the LGM ice cover (blue-green) and overdeepened structures below the present day land surface (grey). (B) – Detailed map of the Wehntal with the location of previous (white circles) and present (black circles) sites investigated in the village of Niederweningen (modified after Dehnert et al., 2012). LGM, last glaciation maximum.

Fig 2.

Logs of the cores NW2018/2 and NW2018/3 illustrating the LTs, lithology and OSL sample locations as well as the layer model used for the individual OSL samples. LTs, lithotypes; OSL, optically stimulated luminescence.
Logs of the cores NW2018/2 and NW2018/3 illustrating the LTs, lithology and OSL sample locations as well as the layer model used for the individual OSL samples. LTs, lithotypes; OSL, optically stimulated luminescence.

Fig 3.

Characterisation of luminescence properties exemplified for sample NW19-3-8. Shown are (A) OSL and (B) IRSL decay curves together with the sensitivity change observed during the course of the SAR protocol (plot of Tn/Tx), (C) dose–response curves for both OSL and IRSL, and (D) plot of mean (CAM) OSL versus IRSL De values. IRSL, infrared stimulated luminescence; OSL, optically stimulated luminescence; SAR, single-aliquot regenerative dose; CAM, Central Age Model.
Characterisation of luminescence properties exemplified for sample NW19-3-8. Shown are (A) OSL and (B) IRSL decay curves together with the sensitivity change observed during the course of the SAR protocol (plot of Tn/Tx), (C) dose–response curves for both OSL and IRSL, and (D) plot of mean (CAM) OSL versus IRSL De values. IRSL, infrared stimulated luminescence; OSL, optically stimulated luminescence; SAR, single-aliquot regenerative dose; CAM, Central Age Model.

Fig 4.

Gamma ray spectrum of the reference loess material (Koeln Loess). Sample weight: 160.5 g, measurement time: 584,786 s. Selected peaks are labelled with the corresponding nuclide names, red: U-238 daughter nuclides, blue: Th-232 daughter nuclides. The inset focusses on the lower energy range of the spectrum from 0 keV to 400 keV.
Gamma ray spectrum of the reference loess material (Koeln Loess). Sample weight: 160.5 g, measurement time: 584,786 s. Selected peaks are labelled with the corresponding nuclide names, red: U-238 daughter nuclides, blue: Th-232 daughter nuclides. The inset focusses on the lower energy range of the spectrum from 0 keV to 400 keV.

Fig 5.

Comparison of the results of NAA and HR-GS for potassium (A,B), thorium (C,D) and uranium (E,F). HR-GS, high-resolution gamma spectrometry; NAA, neutron activation analyses.
Comparison of the results of NAA and HR-GS for potassium (A,B), thorium (C,D) and uranium (E,F). HR-GS, high-resolution gamma spectrometry; NAA, neutron activation analyses.

Fig 6.

Sediment moisture at the time of sampling plotted versus water absorption capacity. Note that the water absorption capacity of all samples is higher than the sediment moisture. The organic content also influences the water content, with samples with a high organic content featuring higher water contents. Dashed = 1:1 line, dotted line: y = x + 25.
Sediment moisture at the time of sampling plotted versus water absorption capacity. Note that the water absorption capacity of all samples is higher than the sediment moisture. The organic content also influences the water content, with samples with a high organic content featuring higher water contents. Dashed = 1:1 line, dotted line: y = x + 25.

Fig 7.

Illustrating the impact of different water contents on the IRSL ages of core NW18/2 (A,B) and NW18/3 (C,D). A and C show the absolute values, whereas B and D display the ratio in comparison to the estimated water content. Closed circles (scenario 1): sediment moisture determined after sampling. Triangles (scenario 2): maximum water adsorption capacity measured in the laboratory, including adding 25% for peat samples. Open circles (scenario 3): estimated long-term water content based on the sediment properties and the water contents determined by scenarios 1 and 2. Scenario 3 is our preference and is used in the following when applying other correction factors than water content. IRSL, infrared stimulated luminescence.
Illustrating the impact of different water contents on the IRSL ages of core NW18/2 (A,B) and NW18/3 (C,D). A and C show the absolute values, whereas B and D display the ratio in comparison to the estimated water content. Closed circles (scenario 1): sediment moisture determined after sampling. Triangles (scenario 2): maximum water adsorption capacity measured in the laboratory, including adding 25% for peat samples. Open circles (scenario 3): estimated long-term water content based on the sediment properties and the water contents determined by scenarios 1 and 2. Scenario 3 is our preference and is used in the following when applying other correction factors than water content. IRSL, infrared stimulated luminescence.

Fig 8.

Illustration of the layer model used to analyse the impact of inhomogeneous radiation fields. The parameters t, x1 and x2 describe the location of the sample within the stratigraphic setting.
Illustration of the layer model used to analyse the impact of inhomogeneous radiation fields. The parameters t, x1 and x2 describe the location of the sample within the stratigraphic setting.

Fig 9.

Boxplots of the radionuclide content of each LT. (A) – Potassium, (B) – thorium, (C) – uranium. Note the high variations in K and Th content for LT 2b (silty, organic-rich clays). HRGS, high-resolution gamma spectrometry; LT, lithotype.
Boxplots of the radionuclide content of each LT. (A) – Potassium, (B) – thorium, (C) – uranium. Note the high variations in K and Th content for LT 2b (silty, organic-rich clays). HRGS, high-resolution gamma spectrometry; LT, lithotype.

Fig 10.

Illustrating the impact of layer correction on the IRSL ages of core NW18/2 (A,B) and NW18/3 (C,D), both given as absolute values and a ratio in comparison to the age calculated without layer correction (using the estimated water content, as discussed in Section 4.2). IRSL, infrared stimulated luminescence.
Illustrating the impact of layer correction on the IRSL ages of core NW18/2 (A,B) and NW18/3 (C,D), both given as absolute values and a ratio in comparison to the age calculated without layer correction (using the estimated water content, as discussed in Section 4.2). IRSL, infrared stimulated luminescence.

Fig 11.

Illustrating the impact of different scenarios of correction for radioactive disequilibrium on the IRSL ages of core NW18/2 (A,B) and NW18/3 (C,D). The central column represents a simplified stratigraphy of the sediment sequence for comparison; details are given in Fig. 6. IRSL, infrared stimulated luminescence.
Illustrating the impact of different scenarios of correction for radioactive disequilibrium on the IRSL ages of core NW18/2 (A,B) and NW18/3 (C,D). The central column represents a simplified stratigraphy of the sediment sequence for comparison; details are given in Fig. 6. IRSL, infrared stimulated luminescence.

Listing the three different water contents used to test the influence of water content on dose rate calculations.

Sample Litho-type Organic content (%) Sediment moisture (%) Water absorption capacity (%) Water absorption + 25% (%) Long-term content (%)
NW18/2-11 3f 3 15 38 - 25 ± 5
NW18/2-10 3f 5 20 41 - 30 ± 5
NW18/2-09 3f 3 12 34 - 25 ± 5
NW18/2-21 1b 51 - 160 200 180 ± 10
NW18/2-08 2b 47 96 100 125 110 ± 10
NW18/2-22 2b 36 73 95 119 100 ± 10
NW18/2-23 1a 24 40 96 120 100 ± 10
NW18/2-07 3d 18 57 74 92 75 ± 5
NW18-2-24 1c 51 21 68 85 75 ± 5
NW18/2-06 2b 20 43 77 96 75 ± 5
NW18/2-25 3c 7 - 62 - 60 ± 5
NW18/2-05 3c 2 25 50 - 40 ± 5
NW18/3-11 3f 17 24 48 - 40 ± 5
NW18/3-21 3f 24 - 64 - 55 ± 5
NW18/3-10 2b 6 27 59 - 45 ± 5
NW18/3-09 3f 3 17 40 - 30 ± 5
NW18/3-22 1b 20 35 54 67 60 ± 5
NW18/3-23 3c 15 29 54 67 60 ± 5
NW18/3-08 3b 2 19 42 - 35 ± 5

Overview of samples and their sedimentary context.

Sample Depth (cm) Sedimentary context
NW18/2-11 148 Located within a thick sequence of light grey to dark grey sandy, muddy silts
NW18/2-10 224 Same as aNW18/2-11, with the sand fraction more dominant
NW18/2-09 375 Located about 40 cm above the peat-rich interval in a dark grey silt, with 15–cm-thick organic-rich silty clay separating the sampled silt from the uppermost peat
NW18/2-21 430 Within the topmost muddy-silty peat, which has a thickness of ~30 cm. Over and underlain by organic-rich silty clays
NW18/2-08 442 Located at the top of 20-cm-thick silty clay, which sits in between two at least 30-cm-thick compacted silty peat layers
NW18/2-22 455 Same as NW18/2-08 but at the bottom of the silty clay layer
NW18/2-23 530 Within a thin (~15 cm) silty gyttia layer, which is over and underlain by black muddy peats with few wood fragments
NW18/2-07 545 Within a thin (~10 cm) organic-rich sandy silt with plant remains. Overlain by black muddy peats and underlain by a dark brown peat with many large wood fragments
NW18-2-24 570 Within a dark brown silty peat with many large wooden fragments, overlain by a thin (~10 cm) organic-rich sandy silt with plant remains and overlying a thick dark grey silty clay with organic-rich layers
NW18/2-06 610 Located at the top of dark grey silty clay with organic-rich layers, overlain by a dark grey organic-rich silt
NW18/2-25 749 Located within a thin (~15 cm) light grey to white silt with small plant remains and mollusc shells which is interbedded between a black muddy peat (top) and silty gyttia (bottom)
NW18/2-05 788 Within a thick light grey silt with mollusc shells
NW18/3-11 232 Located within a grey sandy, pebbly silt with plant remains. Overlain by a graded sand and overlying a compacted thin black silty peat
NW18/3-21 323 A thin (8 cm) grey silt with small plant remains, interbedded within compacted silted peats
NW18/3-10 335 Dark grey silty organic-rich clay, over and underlain by very thin (<5 cm) silt and sandy layers which are packaged within black peats
NW18/3-09 406 Within a dark grey sandy silt with plant remains and peat fragments. Overlain by a dark grey pebbly sand and underlain by a black compacted peat
NW18/3-22 438 Within a thick (~45 cm) black peat layer, which is over and underlain by organic-rich grey silts
NW18/3-23 496 Within a thin (10 cm) light grey silt with mollusc shells. Overlain by a dark brown organic-rich sand silt and overlying a thin layer of black peat
NW18/3-08 518 At the top of a thick (>1 m) light grey sandy silt, overlain by an organic-rich sand silt with small plant remains

Mean De values (CAM) and resulting ages with sample code, composite depth and number of replicate measurement (quartz/feldspar) for OSL and IRSL.

Sample Depth (cm) n OSL De (Gy) IRSL De (Gy) OSL Age1 (ka) OSL Age2 (ka) OSL Age3 (ka) IRSL Age1 (ka) IRSL Age2 (ka) IRSL Age3 (ka)
NW18/2-11 148 5/7 303.9 ± 8.7 341.6 ± 11.6 105 ± 5 105 ± 5 103...107 ± 5 107 ± 7 107 ± 7 105...109 ± 7
NW18/2-10 224 5/7 235.4 ± 4.7 302.8 ± 9.3 79.6 ± 3.3 79.8 ± 3.3 80...81 ± 3 93.1 ± 6.1 93.3 ± 6.1 94...95 ± 6
NW18/2-09 375 5/7 212.3 ± 4.8 190.8 ± 3.3 85.6 ± 3.6 85.5 ± 3.6 86...87 ± 4 70.9 ± 3.9 70.8 ± 3.9 71...72 ± 4
NW18/2-21 430 -/6 - 206.3 ± 5.1 - - - 171 ± 13 167 ± 13 177...197 ± 13
NW18/2-08 442 -/7 - 191.8 ± 7.0 - - - 74.1 ± 6.4 77.8 ± 7.0 91...96 ± 7
NW18/2-22 455 5/6 165.9 ± 10.0 223.1 ± 5.2.4 100.1 ± 7.6 103.9 ± 7.9 109...115 ± 8 119 ± 9 123 ± 10 129...138 ± 10
NW18/2-23 530 -/6 - 148.9 ± 5.5 - - - 37.5 ± 3.7 39.9 ± 4.2 28...32 ± 3
NW18/2-07 545 -/7 - 197.8 ± 3.6 - - - 64.5 ± 5.0 66.3 ± 5.2 66...69 ± 5
NW18-2-24 570 -/6 - 254.7 ± 7.5 - - - 125 ± 7 115 ± 10 87...102 ± 8
NW18/2-06 610 -/7 - 248.0 ± 4.6 - - - 68.8 ± 5.5 68.8 ± 5.5 69...71 ± 6
NW18/2-25 749 5/6 246.50 ± 9.0 310.80 ± 8.7 144 ± 8 135 ± 7 118...134 ± 7 164 ± 11 155 ± 10 133...151 ± 11
NW18/2-05 788 -/7 - 170.8 ± 4.6 - - - 84.4 ± 5.5 84.4 ± 5.5 no dis.
NW18/3-11 232 5/7 202.6 ± 6.5 198.4 ± 5.2 67.9 ± 3.5 69.0 ± 3.5 70 ± 4 59.7 ± 4.2 60.7 ± 2.7 61 ± 4
NW18/3-21 323 5/6 181.8 ± 10.4 243.0 ± 5.7 67.0 ± 4.7 72.9 ± 5.3 73...74 ± 5 79.7 ± 5.8 86.0 ± 6.7 86...88 ± 7
NW18/3-10 335 5/6 276.0 ± 6.3 288.0 ± 7.6 82.5 ± 3.7 85.2 ± 3.9 no dis. 77.3 ± 5.4 79.6 ± 5.7 no dis.
NW18/3-09 406 -/7 - 310.8 ± 6.6 - - - 92.6 ± 7.5 93.5 ± 5.9 89...93 ± 6
NW18/3-22 438 -/6 - 242.9 ± 5.8 - - - 86.2 ± 6.6 85.9 ± 6.5 89...96 ± 7
NW18/3-23 496 5/5 202.2 ± 6.0 236.2 ± 7.3 97.0 ± 4.5 97.1 ± 4.5 no dis. 102 ± 7 103 ± 7 no dis.
NW18/3-08 518 5/7 239.8 ± 5.7 259.7 ± 4.9 102 ± 5 101 ± 4 no dis. 99.9 ± 6.2 99.5 ± 6.1 no dis.

Calculated dose rate data with sample code and composite depth, and estimated long-term water content.

Sample Depth (cm) W (%) Dose rate Q1 (Gy ka−1) Dose rate Q2 (Gy ka−1) Dose rate Q3 (Gy ka−1) Dose rate F1 (Gy ka−1) Dose rate F2 (Gy ka−1) Dose rate F3 (Gy ka−1)
NW18/2-11 148 25 ± 5 2.89 ± 0.14 2.89 ± 0.14 2.84...2.94 ± 0.16 3.18 ± 0.22 3.18 ± 0.22 3.12...3.24 ± 0.25
NW18/2-10 224 30 ± 5 2.96 ± 0.12 2.95 ± 0.12 2.91...2.93 ± 0.13 3.25 ± 0.21 3.24 ± 0.21 3.18...3.21 ± 0.23
NW18/2-09 375 25 ± 5 2.48 ± 0.10 2.48 ± 0.10 2.44...2.47 ± 0.12 2.69 ± 0.15 2.70 ± 0.15 2.66...2.69 ± 0.15
NW18/2-21 430 180 ± 10 - - - 1.21 ± 0.09 1.23 ± 0.09 1.05...1.17 ± 0.09
NW18/2-08 442 110 ± 10 - - - 2.59 ± 0.22 2.46 ± 0.22 1.99...2.10 ± 0.19
NW18/2-22 455 100 ± 10 1.66 ± 0.13 1.60 ± 0.12 1.44...1.53 ± 0.15 1.88 ± 0.15 1.82 ± 0.14 1.61...1.73 ± 0.14
NW18/2-23 530 100 ± 10 - - - 3.97 ± 0.40 3.73 ± 0.39 4.59 ± 0.51
NW18/2-07 545 75 ± 5 - - - 3.07 ± 0.24 2.98 ± 0.23 2.85...2.98 ± 0.23
NW18-2-24 570 75 ± 5 - - - 3.12 ± 0.27 3.10 ± 0.27 2.51...2.94 ± 0.27
NW18/2-06 610 75 ± 5 - - - 3.61 ± 0.29 3.60 ± 0.29 3.50...3.58 ± 0.29
NW18/2-25 749 60 ± 5 1.71 ± 0.09 1.82 ± 0.09 1.84...2.09 ± 0.13 1.89 ± 0.12 2.00 ± 0.12 2.06...2.34 ± 0.18
NW18/2-05 788 40 ± 5 - - - 2.02 ± 0.19 2.02 ± 0.19 no dis.
NW18/3-11 232 40 ± 5 2.98 ± 0.15 2.93 ± 0.15 2.88...2.90 ± 0.17 3.32 ± 0.23 3.27 ± 0.15 3.24...3.25 ± 0.24
NW18/3-21 323 55 ± 5 2.72 ± 0.19 2.49 ± 0.18 2.47...2.49 ± 0.23 3.05 ± 0.22 2.82 ± 0.22 2.75...2.81 ± 0.23
NW18/3-10 335 45 ± 5 3.35 ± 0.15 3.24 ± 0.15 no dis. 3.73 ± 0.26 3.62 ± 0.26 no dis.
NW18/3-09 406 30 ± 5 - - - 3.36 ± 0.27 3.32 ± 0.21 3.34...3.51 ± 0.24
NW18/3-22 438 60 ± 5 - - - 2.82 ± 0.21 2.83 ± 0.21 2.54...2.74 ± 0.21
NW18/3-23 496 60 ± 5 2.01 ± 0.11 2.08 ± 0.10 no dis. 2.31 ± 0.15 2.30 ± 0.15 no dis.
NW18/3-08 518 35 ± 5 2.36 ± 0.10 2.37 ± 0.10 no dis. 2.60 ± 0.16 2.61 ± 0.16 no dis.

Concentration of dose rate-relevant elements (K, Th, U) determined by both NAA and HR-GS.

Sample Depth (cm) KNAA (%) KGS (%) ThNAA (ppm) ThGS (ppm) U-238NAA (ppm) U-238GS (ppm) Ra-226GS (ppm UE) U/Ra Ratio
Loess Ref - 1.11 ± 0.01 1.11 ± 0.01 8.27 ± 0.21 8.27 ± 0.21 2.75 ± 0.09 2.75 ± 0.09 - -
Loess Test - 1.04 ± 0.06 1.08 ± 0.02 7.68 ± 0.39 8.27 ± 0.45 2.49 ± 0.19 2.33 ± 0.23 2.62 ± 0.13 -
NW18/2-11 148 1.85 ± 0.09 1.68 ± 0.03 8.2 ± 0.4 7.86 ± 0.17 2.01 ± 0.10 2.02 ± 0.13 2.99 ± 0.08 0.67
NW18/2-10 224 1.72 ± 0.09 1.85.0.04 8.7 ± 0.4 8.26 ± 0.16 8.38 ± 0.42 7.36 ± 0.20 3.19 ± 0.06 2.31
NW18/2-09 375 1.65 ± 0.08 1.75 ± 0.04 5.8 ± 0.3 5.34 ± 0.18 3.37 ± 0.22 2.94 ± 0.14 2.14 ± 0.06 1.37
NW18/2-21 430 0.61 ± 0.03 0.70 ± 0.02 7.0 ± 0.4 7.54 ± 0.30 5.03 ± 0.30 7.30 ± 0.24 4.46 ± 0.13 1.64
NW18/2-08 442 1.07 ± 0.06 1.31 ± 0.03 9.2 ± 0.5 10.51 ± 0.20 5.20 ± 0.31 6.57 ± 0.27 5.66 ± 0.35 1.16
NW18/2-22 455 0.90 ± 0.05 0.96 ± 0.02 7.9 ± 0.4 8.28 ± 0.26 4.69 ± 0.27 5.98 ± 0.27 4.49 ± 0.15 1.33
NW18/2-23 530 0.79 ± 0.04 0.86 ± 0.02 11.6 ± 0.6 12.59 ± 0.36 22.20 ± 1.11 29.03 ± 0.64 15.24 ± 0.27 1.90
NW18/2-07 545 1.31 ± 0.07 1.44 ± 0.03 9.1 ± 0.5 9.18 ± 0.31 13.79 ± 0.68 12.29 ± 0.35 7.56 ± 0.21 1.63
NW18-2-24 570 0.81 ± 0.04 0.84 ± 0.02 8.8 ± 0.4 8.70 ± 0.20 21.47 ± 1.09 24.88 ± 0.58 9.42 ± 0.09 2.64
NW18/2-06 610 1.22 ± 0.06 1.46 ± 0.03 16.4 ± 0.8 17.15 ± 0.35 9.80 ± 0.47 9.79 ± 0.32 7.80 ± 0.22 1.26
NW18/2-25 749 1.16 ± 0.06 1.25 ± 0.03 8.5 ± 0.4 8.70 ± 0.20 5.62 ± 0.36 5.14 ± 0.20 3.88 ± 0.13 1.32
NW18/2-05 788 1.13 ± 0.06 1.21 ± 0.03 6.7 ± 0.3 6.55 ± 0.14 2.05 ± 0.1 1.73 ± 0.12 2.05 ± 0.13 0.85
NW18/3-11 232 1.52 ± 0.08 1.69 ± 0.04 9.5 ± 0.5 9.92 ± 0.09 12.57 ± 0.68 12.10 ± 0.33 4.34 ± 0.18 2.79
NW18/3-21 323 1.44 ± 0.07 1.47 ± 0.03 11.5 ± 0.6 11.96 ± 0.39 5.62 ± 0.24 6.71 ± 0.24 4.67 ± 0.07 1.44
NW18/3-10 335 1.84 ± 0.09 1.98 ± 0.04 14.4 ± 0.7 14.13 ± 0.22 4.17 ± 0.21 4.00 ± 0.20 4.45 ± 0.07 0.90
NW18/3-09 406 1.86 ± 0.10 1.92 ± 0.04 10.9 ± 0.6 10.21 ± 0.22 2.57 ± 0.17 2.14 ± 0.13 2.93 ± 0.03 0.73
NW18/3-22 438 1.20 ± 0.06 1.28 ± 0.03 8.8 ± 0.4 8.32 ± 0.19 8.03 ± 0.40 8.48 ± 0.26 5.73 ± 0.12 1.48
NW18/3-23 496 1.47 ± 0.08 1.53 ± 0.03 8.5 ± 0.4 8.38 ± 0.13 3.03 ± 0.20 3.05 ± 0.16 2.95 ± 0.06 1.03
NW18/3-08 518 1.40 ± 0.07 1.53 ± 0.03 8.6 ± 0.4 8.22 ± 0.17 2.50 ± 0.17 2.17 ± 0.14 2.39 ± 0.08 0.91

Results of repeated gamma spectrometry measurements of reference material ‘Koeln Loess’ in comparison with NAA and reference values.

Parent nuclide Daughter nuclide Energy (keV) Meas. 1 12/2019 Meas. 2 06/2020 Meas. 3 10/2020 Meas. 4 4/2021 NAA Reference Potts et al. (2003) (IAG, 2022)
Activity (Bq/kg)
U-238 Th-234 63.3 28.0 ± 1.2 35.6 ± 1.4 33.9 ± 1.4 34.3 ± 1.4
Pb-214 295.2 32.1 ± 0.7 34.1 ± 0.7 33.8 ± 0.7 34.2 ± 0.7
Pb-214 351.9 32.0 ± 0.7 33.2 ± 0.7 33.6 ± 0.7 33.3 ± 0.7
Bi-214 609.3 31.9 ± 0.7 33.3 ± 0.7 33.5 ± 0.7 33.0 ± 0.7
Bi-214 1120.3 29.5 ± 0.6 36.5 ± 0.8 33.5 ± 0.7 35.1 ± 0.7
Bi-214 1764.5 32.8 ± 0.7 34.1 ± 0.7 33.6 ± 0.7 32.7 ± 0.7
Mean 31.6 ± 1.3 34.2 ± 1.3 33.6 ± 0.1 33.6 ± 0.9
Concentration (ppm) 2.56 ± 0.10 2.77 ± 0.10 2.72 ± 0.01 2.72 ± 0.08 2.49 ± 0.19 2.70 ± 0.19 (2.75 ± 0.09)
Th-232 Ac-228 338.3 32.4 ± 0.7 32.5 ± 0.7 34.1 ± 0.8 32.0 ± 0.7
Ac-228 911.1 34.0 ± 0.8 32.9 ± 0.7 32.4 ± 0.7 32.7 ± 0.7
Ac-228 969.1 34.2 ± 0.8 33.3 ± 0.7 31.7 ± 0.7 31.7 ± 0.7
Pb-212 238.6 32.1 ± 0.6 33.3 ± 0.7 33.1 ± 0.7 32.8 ± 0.6
Tl-208 583.2 33.3 ± 0.8 33.7 ± 0.8 33.0 ± 0.7 33.6 ± 0.8
Mean 33.1 ± 1.0 33.1 ± 0.5 32.8 ± 1.8 32.5 ± 0.7
Concentration (ppm) 8.16 ± 0.24 8.16 ± 0.12 8.10 ± 0.45 8.02 ± 0.17 7.68 ± 0.39 8.11 ± 0.47 (8.27 ± 0.21)
K-40 - 1460.8 339.1 ± 7.0 336.5 ± 6.8 335.0 ± 6.8 335.6 ± 6.8
Concentration (%) 1.10 ± 0.02 1.09 ± 0.02 1.08 ± 0.02 1.09 ± 0.02 1.04 ± 0.06 1.08 ± 0.02 (1.11 ± 0.01)
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