Fig 1
Flowchart of procedures applied in the case of different cross-calibration approaches used in the study. (A) MAR measurements on α-irradiated aliquots from both laboratories. (B) α dose recovery of known α-doses using SAR. (C) α dose recovery of a known γ-dose using SAR. MAR, Multiple aliquot regeneration; SAR, Single aliquot regeneration.
Fig 2
MAR dose-response curves generated by the Szeged RISØ α-source with unknown dose rate and the normalised OSL/IRSL of calibration doses administered by the known dose rate Bayreuth Littlemore α-source. (A) quartz sample OSL, (B) polymineral sample first temperature IR50 and (C) polymineral sample pIRIR290. MAR, multiple aliquot regeneration; OSL, optically stimulated luminescence; pIRIR, Post-IR IRSL.
Table 1
Szeged a-source dose rates determined by different calibration procedures.
| Sample | Procedure | Calculation | Dose rate (Gy/s) |
|---|---|---|---|
| Quartz (OSZ 1107) | MAR OSL | OSLBAY → DαSZE(s) | 0.071 ± 0.002 |
| Polymineral (OSZ 1614) | MAR IR50 | 0.109 ± 0.012 | |
| MAR pIRIR290 | 0.085 ± 0.010 | ||
| Quartz (OSZ 1107) | α-SAR OSL | 0.076 ± 0.004 | |
| α-dose recovery | |||
| RISØ quartz (Batch 108) | α-SAR OSL | 0.086 ± 0.005 | |
| γ-dose recovery |
[i]
- OSLBAY:
Normalised luminescence intensities measured on aliquots irradiated at Bayreuth.
- DαSZE(s):
Time equivalent Szeged α-dose.
- DαBAY(s):
Time equivalent Bayreuth α-dose.
- D*αSZE:
Dose rate of Szeged α-source (Gy/s).
- D*αBAY:
Dose rate of Bayreuth α-source (Gy/s).
- b:
y-intercept of a linear function.
- m:
slope of a linear function.
[ii] MAR, multiple aliquot regeneration; OSL, optically stimulated luminescence; pIRIR, post-IR IRSL; SAR, single aliquot regeneration.
Fig 3
Alpha SAR dose recovery of previously administered, incrementally increasing α-doses. Irradiation was made with the unknown dose rate Szeged α-source, while measurements were made at Bayreuth. SAR, Single aliquot regeneration.
Fig 4
Abanico plot (Dietze et al., 2016) of equivalent α-doses of the 4.81 Gy γ-dose carried by the RISØ calibration quartz, measured by the two readers at Szeged and Bayreuth.
Fig 5
Abanico plot (Dietze et al., 2016) of a-values concerning the RISØ calibration quartz and sample OSZ1107. Both datasets were measured at Szeged. The a-values are calculated by using the dose rate value determined by using the specific sample.
Fig 6
Alpha dose-response curves of sample OSZ1107 and RISØ calibration quartz.
Fig 7
Comparison of α- and β-dose-response curves measured at the two laboratories concerning (A) the RISØ calibration quartz and (B) sample OSZ1107. Effective α-dose stands for the β-dose equivalent of the α-dose administered, the conversion is made using the sample-specific a-value.
Table 2
Environmental dose rates for the quartz and polymineral fraction of the same loess sample, calculated by applying the lowest and highest a-source dose rate received during the cross-calibration process.
| 226Ra (Bq/kg) | 232Th (Bq/kg) | 40K (Bq/kg) | w (%) | Depth (m) | Mineral | D*α-source (Gy/s) | a-value | D*α (Gy/ka) | D*tot (Gy/ka) |
|---|---|---|---|---|---|---|---|---|---|
| 34.7 ± 0.4 | 34.2 ± 0.6 | 390.9 ± 15.1 | 10 ± 2 | 0.9 | Q | 0.071 ± 0.002 | 0.041 ± 0.003 | 0.35 ± 0.04 | 2.89 ± 0.07 |
| 0.086 ± 0.005 | 0.034 ± 0.003 | 0.29 ± 0.03 | 2.83 ± 0.07 | ||||||
| PM | 0.071 ± 0.002 | 0.077 ± 0.003 | 0.65 ± 0.06 | 3.27 ± 0.09 | |||||
| 0.086 ± 0.005 | 0.063 ± 0.004 | 0.54 ± 0.06 | 3.15 ± 0.08 |
[i]
- D*α:
wet alpha dose rate;
- D*tot:
total environmental dose rate; Q, Quartz; PM, Polymineral.