MEASURAND Absorbed dose to water
Radiation quality Accelerator photon beams
Beam quality corresponding to measured TPR_{20,10} between 0.63 (included) and 0.71 (excluded), which approximately corresponds to PDD(10) between 63 % (included) and 71 % (excluded)
Degrees of equivalence represented by D_{i} = (x_{I}  x_{R}) /x_{R }and its expanded uncertainty U_{i} at a 95 % level of confidence, both expressed in mGy/Gy.
MEASURAND Absorbed dose to water
Radiation quality Accelerator photon beams
Beam quality corresponding to measured TPR_{20,10} between 0.71 (included) and 0.77 (excluded), which approximately corresponds to PDD(10) between 71 % (included) and 78 % (excluded)
Degrees of equivalence represented by D_{i} = (x_{I}  x_{R}) /x_{R }and its expanded uncertainty U_{i} at a 95 % level of confidence, both expressed in mGy/Gy.
MEASURAND Absorbed dose to water
Radiation quality Accelerator photon beams
Beam quality corresponding to measured TPR_{20,10} between 0.77 (included) and 0.81 (included), which approximately corresponds to PDD(10) between 78 % (included) and 85 % (included)
Degrees of equivalence represented by D_{i} = (x_{I}  x_{R}) /x_{R }and its expanded uncertainty U_{i} at a 95 % level of confidence, both expressed in mGy/Gy.
MEASURAND Absorbed dose to water
Radiation quality Accelerator photon beams
Beam quality corresponding to measured TPR_{20,10} between 0.63 (included) and 0.71 (excluded), which approximately corresponds to PDD(10) between 63 % (included) and 71 % (excluded)
Degrees of equivalence represented by D_{i} = (x_{I}  x_{R}) /x_{R }and its expanded uncertainty U_{i} at a 95 % level of confidence, both expressed in mGy/Gy.
LAB_{i}  D_{i}  U_{neg,i}  U_{pos,i}  

mGy/Gy 
mGy/Gy 
mGy/Gy 

NIST  3.5  11.4  
NPL  2.7  12.4  
VSL  4.1  10.8  
NMIJ  3.4  9.4  
NIM  8.3  12.0  
KRISS  7.8  12.0  
METAS  1.7  13.2  
LNELNHB  2.3  11.8  
NRC  4.0  11.6  
PTB  2.6  11.4  
ARPANSA  4.5  12.4 
MEASURAND Absorbed dose to water
Radiation quality Accelerator photon beams
Beam quality corresponding to measured TPR_{20,10} between 0.71 (included) and 0.77 (excluded), which approximately corresponds to PDD(10) between 71 % (included) and 78 % (excluded)
Degrees of equivalence represented by D_{i} = (x_{I}  x_{R}) /x_{R }and its expanded uncertainty U_{i} at a 95 % level of confidence, both expressed in mGy/Gy.
LAB_{i}  D_{i}  U_{neg,i}  U_{pos,i}  

mGy/Gy 
mGy/Gy 
mGy/Gy 

NPL  0.5  13.2  
VSL  4.2  12.8  
NMIJ  4.1  11.0  
NIM  5.9  11.8  
KRISS  5.6  12.0  
METAS  3.2  13.2  
LNELNHB  3.8  11.8  
NRC  3.0  11.6  
PTB  0.6  11.4  
ARPANSA  5.1  12.4 
MEASURAND Absorbed dose to water
Radiation quality Accelerator photon beams
Beam quality corresponding to measured TPR_{20,10} between 0.77 (included) and 0.81 (included), which approximately corresponds to PDD(10) between 78 % (included) and 85 % (included)
Degrees of equivalence represented by D_{i} = (x_{I}  x_{R}) /x_{R }and its expanded uncertainty U_{i} at a 95 % level of confidence, both expressed in mGy/Gy.
LAB_{i}  D_{i}  U_{neg,i}  U_{pos,i}  

mGy/Gy 
mGy/Gy 
mGy/Gy 

NIST  4.2  11.8  
NPL  4.3  16.2  
VSL  1.0  14.8  
KRISS  8.5  12.0  
METAS  1.2  13.2  
LNELNHB  4.4  11.8  
NRC  3.9  11.6  
PTB  0.3  11.4  
ARPANSA  4.9  12.4 
Metrology area, Subfield  Ionizing Radiation, Section I (x and gamma rays, electrons) 
Description  Measurement of absorbed dose to water for highenergy photon beams 
Time of measurements  2009  
Status  Continuous, approved for equivalence 
References  
Measurand  Absorbed dose to water relative to the BIPM evaluation 
Parameters  Radiation type: accelerator beams  high energy photons 
Transfer device  Calorimeters 
Comparison type  Key Comparison 
Consultative Committee  CCRI (Consultative Committee for Ionizing Radiation) 
Conducted by  BIPM (Bureau International des Poids et Mesures) 
Comments  The Final Report for each bilateral comparsion is listed in the tab "Participants" First results published on 8 July 2013 Most recent update on 26 May 2023 
Pilot institute 
BIPM
Bureau International des Poids et Mesures BIPM  International Organization 
Contact person  C. Kessler +33 (0) 1 45 07 70 84 
Pilot laboratory  

BIPM 
Bureau International des Poids et Mesures, BIPM  International Organization, N/A 
ARPANSA 
Australian Radiation Protection and Nuclear Safety Agency, Australia, APMP 
2012  
2022 
KRISS 
Korea Research Institute of Standards and Science, Korea, Republic of, APMP 
2017 
LNELNHB 
Commissariat à l'énergie atomique / Laboratoire National Henri Becquerel, France, EURAMET 
2012  
2020 
METAS 
Federal Institute of Metrology, Switzerland, EURAMET 
2018 
NIM 
National Institute of Metrology, China, APMP 
2016 
NIST 
National Institute of Standards and Technology, United States, SIM 
2010 
NMIJ AIST 
National Metrology Institute of Japan, Japan, APMP 
2015 
NPL 
National Physical Laboratory, United Kingdom, EURAMET 
2013  
2014 
NRC 
National Research Council, Canada, SIM 
2009  
2020 

PTB 
PhysikalischTechnische Bundesanstalt, Germany, EURAMET 
2010  
2021 
VSL 
VSL, Netherlands, EURAMET 
2014 
This page proposes printout on A4 paper (portrait) of the comparison details (best printed out using a black and white printer).
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MEASURAND Absorbed dose to water
Radiation quality Accelerator photon beams
The key comparison reference value is the BIPM determination of absorbed dose to water in an accelerator beam.
The degree of equivalence of each laboratory i with respect to the key comparison reference value x_{R} is given by a pair of terms: the relative difference D_{i }and U_{i}_{ }= 2u_{i}, its expanded uncertainty (k = 2), both expressed in mGy/Gy.
When required, the degree of equivalence between two laboratories i and j can be evaluated by a pair of terms: D_{ij }= D_{i}  D_{j }and U_{ij} = 2u_{ij}, its expanded uncertainty (k = 2), both expressed in mGy/Gy. In evaluating u_{ij}, account should be taken of correlation between u_{i} and u_{j}.
MEASURAND Absorbed dose to water
Radiation quality Accelerator photon beams
The key comparison reference value is the BIPM determination of absorbed dose to water in an accelerator beam.
The degree of equivalence of each laboratory i with respect to the key comparison reference value x_{R} is given by a pair of terms: the relative difference D_{i }and U_{i}_{ }= 2u_{i}, its expanded uncertainty (k = 2), both expressed in mGy/Gy.
When required, the degree of equivalence between two laboratories i and j can be evaluated by a pair of terms: D_{ij }= D_{i}  D_{j }and U_{ij} = 2u_{ij}, its expanded uncertainty (k = 2), both expressed in mGy/Gy. In evaluating u_{ij}, account should be taken of correlation between u_{i} and u_{j}.
EASURAND Absorbed dose to water
Radiation quality Accelerator photon beams
The key comparison reference value is the BIPM determination of absorbed dose to water in an accelerator beam.
The degree of equivalence of each laboratory i with respect to the key comparison reference value x_{R} is given by a pair of terms: the relative difference D_{i }and U_{i}_{ }= 2u_{i}, its expanded uncertainty (k = 2), both expressed in mGy/Gy.
When required, the degree of equivalence between two laboratories i and j can be evaluated by a pair of terms: D_{ij }= D_{i}  D_{j }and U_{ij} = 2u_{ij}, its expanded uncertainty (k = 2), both expressed in mGy/Gy. In evaluating u_{ij}, account should be taken of correlation between u_{i} and u_{j}.
MEASURAND Absorbed dose to water
Radiation quality Accelerator photon beams
x_{i} : ratio of the measurement result of the laboratory i to that of the BIPM
u_{i} : combined standard uncertainty of the ratio x_{i}
Beam quality corresponding to measured TPR_{20,10} between 0.63 (included) and 0.71 (excluded), which approximately corresponds to PDD(10) between 63 % (included) and 71 % (excluded)
Lab_{i}  TPR_{20,10}  x_{i}  u_{i}  year of measurement  
NIST  0.674  1.0035  0.0057  2010  
NPL  0.682  0.9973  0.0062  2013  
VSL  0.682  0.9959  0.0054  2014  
NMIJ  0.679  0.9966  0.0047  2015  
NIM  0.687  0.9917  0.0060  2016  
KRISS  0.686  1.0078  0.0060  2017  
METAS  0.686  0.9983  0.0066  2018  
LNELNHB  0.665  0.9977  0.0059  2020  
NRC  0.686  1.0040  0.0058  2020  
PTB  0.686  1.0026  0.0057  2021  
ARPANSA  0.686  0.9955  0.0062  2022 
EASURAND Absorbed dose to water
Radiation quality Accelerator photon beams
x_{i} : ratio of the measurement result of the laboratory i to that of the BIPM
u_{i} : combined standard uncertainty of the ratio x_{i}
Beam quality corresponding to measured TPR_{20,10} between 0.71 (included) and 0.77 (excluded), which approximately corresponds to PDD(10) between 71 % (included) and 78 % (excluded)
Lab_{i}  TPR_{20,10}  x_{i}  u_{i}  year of measurement  
NPL  0.733  0.9995  0.0066  2013  
VSL  0.733  0.9958  0.0064  2014  
NMIJ  0.744  0.9959  0.0055  2015  
NIM  0.740  0.9941  0.0059  2016  
KRISS  0.733  1.0056  0.0060  2017  
METAS  0.733  0.9968  0.0066  2018  
LNELNHB  0.737  0.9962  0.0059  2020  
NRC  0.733  1.0030  0.0058  2020  
PTB  0.733  0.9994  0.0057  2021  
ARPANSA  0.733  0.9949  0.0062  2021 
MEASURAND Absorbed dose to water
Radiation quality Accelerator photon beams
x_{i} : ratio of the measurement result of the laboratory i to that of the BIPM
u_{i} : combined standard uncertainty of the ratio x_{i}
Beam quality corresponding to measured TPR_{20,10} between 0.77 (included) and 0.81 (included), which approximately corresponds to PDD(10) between 78 % (included) and 85 % (included)
Lab_{i}  TPR_{20,10}  x_{i}  u_{i}  year of measurement  
NIST  0.783  0.9958  0.0059  2010  
NPL  0.800  0.9957  0.0081  2013  
VSL  0.800  1.0010  0.0074  2014  
KRISS  0.774  1.0085  0.0060  2017  
METAS  0.774  0.9988  0.0066  2018  
LNELNHB  0.790  0.9956  0.0059  2020  
NRC  0.774  1.0039  0.0058  2020  
PTB  0.774  0.9997  0.0057  2021  
ARPANSA  0.774  0.9951  0.0062  2022 