BIPM.RI(II)-K1.Tb-161
MEASURAND Equivalent activity of 161Tb
Degrees of equivalence represented by Di = (xi - xR) and its expanded uncertainty Ui at a 95 % level of confidence, both expressed in MBq.
Results given in absolute values
BIPM.RI(II)-K1.Tb-161
MEASURAND Equivalent activity of 161Tb
Degrees of equivalence represented by Di = (xi - xR) / xR and its expanded uncertainty Ui at a 95 % level of confidence, both expressed in KBq/MBq.
Results given in relative values
BIPM.RI(II)-K1.Tb-161
MEASURAND Equivalent activity of 161Tb
Degrees of equivalence represented by Di = (xi - xR) and its expanded uncertainty Ui at a 95 % level of confidence, both expressed in MBq.
| LABi | Di | Uneg,i | Upos,i | |
|---|---|---|---|---|
MBq |
MBq |
MBq |
||
| IRA | 8 | 17 | ||
| NPL | -0.2 | 6.9 | ||
| POLATOM | -6 | 12 |
Results given in absolute values
BIPM.RI(II)-K1.Tb-161
MEASURAND Equivalent activity of 161Tb
Degrees of equivalence represented by Di = (xi - xR) / xR and its expanded uncertainty Ui at a 95 % level of confidence, both expressed in KBq/MBq.
| LABi | Di | Uneg,i | Upos,i | |
|---|---|---|---|---|
kBq/MBq |
kBq/MBq |
kBq/MBq |
||
| IRA | 5 | 10 | ||
| NPL | -0.1 | 4.0 | ||
| POLATOM | -3.2 | 7.3 |
Results given in relative values
| Metrology area, Sub-field | Ionizing Radiation, Section II (Measurement of Radionuclides) |
| Description | Activity of radionuclide Tb-161 |
| Time of measurements | 2019 |
| Status | Continuous, approved for equivalence |
| Final Reports of the comparisons | |
| Measurand | SIR equivalent activity |
| Transfer device | Radioactive solution |
| Comparison type | Key Comparison |
| Consultative Committee | CCRI (Consultative Committee for Ionizing Radiation) |
| Conducted by | BIPM (Bureau International des Poids et Mesures) |
| Comments | SIR: Système International de Référence, International Reference System First results published on 23 April 2021. Most recent results published on 27 October 2026 |
| Pilot institute |
BIPM
Bureau International des Poids et Mesures BIPM - International Organization |
| Contact person | Romain Coulon |
| Pilot laboratory | |
|---|---|
| BIPM |
Bureau International des Poids et Mesures, BIPM - International Organization, N/A |
| IRA |
Institut Universitaire de Radiophysique Appliquée, Switzerland, EURAMET |
| 2019 |
| NPL |
National Physical Laboratory, United Kingdom, EURAMET |
| 2022 |
|
| POLATOM |
Radioisotope Centre Polatom, Poland, EURAMET |
| 2025 |
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BIPM.RI(II)-K1.Tb-161
MEASURAND Equivalent activity of 161Tb
Key comparison reference value: the SIR key comparison reference value xR for this radionuclide is 1701.8 MBq, with a standard uncertainty uR equal to 36 MBq
(see Section 4.1 of the BIPM.RI(II)-K1.Tb-161 2026 Final report). The value xi is taken as the equivalent activity for a laboratory i.
The degree of equivalence of each laboratory with respect to the reference value is given by a pair of terms:
Di = (xi - xR) and Ui its expanded uncertainty (k = 2), both expressed in MBq, and
Ui = 2((1 - 2wi )ui2 + uR2 )1/2 , where wi is the weight of laboratory i contributing to the calculation of xR.
The degrees of equivalence are also given in relative terms by Di = (xi - xR) /xR and Ui /xR , both expressed in kBq/MBq.
BIPM.RI(II)-K1.Tb-161
MEASURAND Equivalent activity of 161Tb
xi result of measurement carried out in the SIR for the sample submitted by laboratory i, Labi
ui combined standard uncertainty of xi
| Labi | xi | ui | Date of measurement | |
| kBq | kBq | |||
| IRA | 1710 | 10 | 2019-08-29 | |
| NPL | 1701.6 | 3.4 | 2022-03-17 | |
| POLATOM | 1696.3 | 7.3 | 2025-04-11 |
