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Main text Since 1976, 23 laboratories have submitted 44 samples of 134Cs to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Cs-134. In the last few years, the POLATOM (Poland), the NRC (Canada), the LNMRI-IRD (Brazil) and the PTB (Germany) participated in the comparison and the key comparison reference value (KCRV) has been updated. The degrees of equivalence between each equivalent activity measured in the SIR or linked to the SIR from the APMP.RI(II)-K2.Cs-134 comparison and the updated KCRV have been calculated and the results are given in the form of a table. A graphical representation is also given. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Main text Three new participations in the BIPM.RI(II)-K1.I-131 comparison have been added to the previous results and this has produced a revised value for the key comparison reference value (KCRV), calculated using the power-moderated weighted mean. A link has been made to the CCRI(II)-S6.I-131 comparison piloted by the International Atomic Energy Agency (IAEA) in 2006, based on the participation of CMI-IIR in both comparisons. One NMI used the S6 comparison to update its degree of equivalence. The results of two NMIs in the CCRI(II)-S6.I-131 comparison were superseded by a more recent APMP.RI(II)-K2.I-131 comparison. The degrees of equivalence between each equivalent activity measured in the International Reference System (SIR) and the KCRV have been calculated and the results are given in the form of a table for the latest results in the BIPM.RI(II)-K1.I-131, and the linked CCRI(II)-S6.I-131, APMP.RI(II)-K2.I-131 and EURAMET.RI(II)-K2.I-131 comparisons. A graphical presentation is also given. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Main text Since 1976, 15 laboratories have submitted 39 samples of 88Y to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Y-88. Recently, the LNE-LNHB (France) and the BEV (Austria) participated in the comparison and the key comparison reference value (KCRV) has been updated. The degrees of equivalence between each equivalent activity measured in the SIR and the updated KCRV have been calculated and the results are given in the form of a table. A graphical presentation is also given. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Main text Since 1979, 8 laboratories have submitted 20 samples of 201Tl to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifer BIPM.RI(II)-K1.Tl-201. The NIST (United States) participated in the comparison and the key comparison reference value (KCRV) has been updated. The degrees of equivalence between each equivalent activity measured in the SIR and the updated KCRV have been calculated and the results are given in the form of a table. A graphical presentation is also given. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Main text Three new participations in the BIPM.RI(II)-K1.Co-57 comparison have been added to the previous results and this has produced a revised value for the key comparison reference value (KCRV), calculated using the power-moderated weighted mean. A link has been made to the CCRI(II)-S6.Co-57 comparison piloted by the International Atomic Energy Agency (IAEA) in 2008 for which one sample of the 57Co radioactive solution was sent to the SIR. Two NMIs used the S6 comparison to update their degree of equivalence. The degrees of equivalence between each equivalent activity measured in the International Reference System (SIR) and the KCRV have been calculated and the results are given in the form of a table for the remaining seven NMIs in the BIPM.RI(II)-K1.Co-57 comparison and the three eligible participants in the CCRI(II)-S6.Co-57 comparison. A graphical presentation is also given. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Main text Since 2014, 3 laboratories have submitted 3 samples of 223Ra to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Ra-223. The NPL (United Kingdom), the PTB (Germany) and the LNE-LNHB (France) participated in the comparison and the key comparison reference value (KCRV) has been calculated for the first time. The degrees of equivalence between each equivalent activity measured in the SIR and the KCRV have been calculated and the results are given in the form of a table. A graphical presentation is also given. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Main text Since 1978, 10 laboratories have submitted 17 samples of 67Ga to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Ga-67. The PTB (Germany) and the NIST (United States) participated in the comparison. The key comparison reference value (KCRV) has been re-calculated using the power-moderated weighted mean. The degrees of equivalence between each equivalent activity measured in the SIR and the KCRV have been calculated and the results are given in the form of a table. A graphical presentation is also given. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Main text Since 1983, 6 laboratories have submitted 7 samples of 110mAg to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Ag-110m. Recently, the PTB (Germany) participated in the comparison and the key comparison reference value (KCRV) has been updated. The degrees of equivalence between each equivalent activity measured in the SIR and the updated KCRV have been calculated and the results are given in the form of a table. A graphical presentation is also given. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Since 1976, 13 laboratories have submitted 29 samples of 22Na to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)- K1.Na-22. Recently, the LNE-LNHB (France) participated in the comparison and the key comparison reference value (KCRV) has been updated. The degrees of equivalence between each equivalent activity measured in the SIR and the updated KCRV have been calculated and the results are given in the form of a table. A graphical presentation is also given. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Three new participations in the BIPM.RI(II)-K1.Fe-59 comparison have been added to the previous results and this has produced a revised value for the key comparison reference value (KCRV), calculated using the power-moderated weighted mean. A link has been made to the APMP.RI(II)-K2.Fe-59 comparison held in 2014 through the NMIJ who participated in both comparisons. Five NMIs used the K1 or K2 comparison to update their degree of equivalence. The degrees of equivalence between each equivalent activity measured in the International Reference System (SIR) and the KCRV have been calculated and the results are given in the form of a table for the remaining five NMIs in the BIPM.RI(II)-K1.Fe-59 comparison and the eight other participants in the APMP.RI(II)-K2.Fe-59 comparison. A graphical presentation is also given. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

This report summarises the results for the new BIPM.RI(II)-K1.Ge-68 comparison. Six metrology institutes have participated, enabling the first value of the key comparison reference value(KCRV) to be determined. The KCRV was calculated using the power-moderated weighted mean and the results. A link has been made to the CCRI(II)-K2.Ge-68 comparison held in 2015 through the NIST, NIM,IRA-METAS and the LNE-LNHB who participated in both comparisons. One NMI used the K2 comparison to update their degree of equivalence. The degrees of equivalence between each equivalent activity measured in the International Reference System (SIR) and the KCRV have been calculated and the results are given in the form of a table for the remaining five NMIs in the BIPM.RI(II)-K1.Ge-68 comparison and the 12 other participants in the CCRI(II)-K2.Ge-68 comparison. A graphical presentation is also given. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

This paper discusses basic theoretical strategies used to deal with measurement uncertainties arising from different experimental situations. It attempts to indicate the most appropriate method of obtaining a reliable estimate of the quantity to be evaluated depending on the characteristics of the data available. The theoretical strategies discussed are supported by experimental detail, and the conditions and results have been taken from examples in the field of radionuclide metrology. Special care regarding the correct treatment of covariances is emphasized because of the unreliability of the results obtained if these are neglected.

This report concerns an international comparison of measurements of a solution of 238Pu that was carried out by 12 participants in 2001. The report includes the degrees of equivalence. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

This article reviews the tools available to assign realistic uncertainties in the field of radioactivity measurements following the prescriptions of the Guide to the Expression of Uncertainty in Measurement. A presentation of different distributions that can be encountered in the analysis of radioactivity measurements is listed, and explained using simple but pertinent examples. Two different methods, a simplified coincidence method and ? counting, are considered, for each of which a detailed uncertainty budget is given. This leads into the characteristics function and the law of propagation of errors that can be used in the evaluation of the total uncertainty. The treatment of correlations, which occur when using the same set of sources and the same decay period for both methods, is also detailed.Subsequently, the analysis of the results of a comparison of activity measurements made by various national laboratories is presented with special care regarding the treatment of correlations that may arise.Finally, the paper also deals with the KCRV determination and the evaluation of degrees of equivalence between laboratories in the general case where the results of BIPM, CCRI and RMO comparisons are linked together. In this case too, as far as is practical, a method to treat correlations is described.While the illustrations in this paper are focused on radioactivity measurements, most of the material presented can, when appropriate, be used in other domains of metrology.

The paper begins with the reasons which led to the installation of the Systeme International de Reference (SIR) more than 30 years ago, describes its main features and presents briefly the way it works. Then more detail is given on the treatment of impurities and on the determination of the efficiency curve. The improvements, which have been made recently to update the SIR and make it more efficient, are also discussed. A brief survey of the status of the present SIR is then given before focusing on the new developments which are in progress to enlarge the scope of the SIR towards measurements of radiopharmaceuticals with short half-lives and of α- and β-particle emitters.

In the analysis of the results of an international comparison it is not exceptional that one or even several values are not in line with the others. It is often difficult to find good reasons—empirical or even statistical—for rejecting these data that may strongly influence the reference value. The median has been recognized as useful for the analysis of comparisons in the field of radioactivity as it avoids the need to cope with outliers. In this paper, the median is used as the key comparison reference value (KCRV) and the formulae necessary to evaluate its uncertainty and that of the degree of equivalence are given. In addition, the weighted median is also defined for use as the KCRV. Equivalent formulae are deduced for this estimator. This paper thus enlarges the range of concepts published previously for KCRV estimators.

Some formulae used for evaluation of the uncertainties of the degree of equivalence between laboratories participating in an international comparison of activity measurement are presented. Two approaches are considered using two different estimators for the key comparison reference value: the arithmetic mean and the weighted mean. For each approach, four cases which can be encountered when dealing with comparison data are detailed. Finally, the effect of the uncertainties on the weights used in the second approach is also considered. This work has been developed for analysis of results of comparisons organized in the field of ionizing radiations, but the formulae are sufficiently general to allow their use for other comparisons. However, correlations between results have not been considered.

Since 2010, four national metrology institutes (NMI) have each submitted a sample of known activity of 60Co to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Co-60. The values of the activity submitted were between about 175 kBq and 1600 kBq. The primary standardization results for the CNEA, Argentina and the BARC, India replace their earlier result of 2003 and 2001, respectively. There are now seventeen results in the BIPM.RI(II)-K1.Co-60 comparison. The key comparison reference value (KCRV) has been updated using the power-moderated weighted mean. The degrees of equivalence between each equivalent activity measured in the SIR and the KCRV have been calculated and the results are given in the form of a table. A graphical presentation is also given. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Since 2009, three national metrology institutes (NMI) have submitted three samples of known activity of 241Am to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Am-241. The values of the activity submitted were between about 3 MBq and 38 MBq. These three results replace their earlier results obtained in the linked CCRI(II)-K2.Am-241 in 2003. There are now five results in the BIPM.RI(II)-K1.Am-241 comparison, 16 results remaining from the CCRI(II)-K2.Am-241 comparison and two results in the COOMET.RI(II)-K2.Am-241 comparison. The degrees of equivalence between each equivalent activity measured in the SIR and the KCRV dating 2007 have been calculated and the results are given in the form of a table. A graphical presentation is also given. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Since 2001, six national metrology institutes (NMI) have submitted seven samples of known activity of 18F to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.F-18. The values of the activity submitted were between about 1 MBq and 18 MBq. The primary standardization result for the LNE-LNHB, France, replaces their earlier result of 2002 and the key comparison reference value (KCRV) has been recalculated. In the frame of the BIPM.RI(II)-K4.F18 comparison, the NPL updated their result in the KCDB. Consequently there are now five results in the BIPM.RI(II)-K1.F-18 comparison. The degrees of equivalence between each equivalent activity measured in the SIR and the updated KCRV have been calculated and the results are given in the form of a table. A graphical presentation is also given. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Since 1975, seven national metrology institutes (NMI) have submitted eleven samples of known activity of 113Sn to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Sn-113. The values of the activity submitted were between about 0.7 MBq and 22 MBq. The present primary standardization results for the PTB, Germany and the LNE-LNHB, France, replace their earlier results of 1989 and 1992, respectively. A key comparison reference value (KCRV) has been evaluated for the first time for 113Sn. There are only three results remaining in the BIPM.RI(II)-K1.Sn-113 comparison, all the previously published ones being outdated. The degrees of equivalence between each of these three equivalent activities measured in the SIR and the KCRV have been calculated and the results are given in the form of a table. A graphical presentation is also given. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

In 2008, the National Physical Laboratory (NPL) submitted one sample of known activity of 56Mn to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Mn-56. The value of the activity submitted was about 290 kBq. There is now one result in the BIPM.RI(II)-K1.Mn-56 comparison. The key comparison reference value (KCRV) has been evaluated for the first time using the NPL result and a BIPM result dating November 1978. The degree of equivalence between the NPL equivalent activity measured in the SIR and the KCRV has been calculated and is reported. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

A new participation in the BIPM.RI(II)-K1.Zn-65 comparison has been added to the previous results. A link has been made to the CCRI(II)-K2.Zn-65 comparison held in 2003 through the measurement of all ampoules of the K2 comparison in the International Reference System (SIR) at the BIPM before dispatch to the participants. This has produced a revised value for the key comparison reference value (KCRV), calculated using the power-moderated weighted mean. Six NMIs used the K2 comparison to update their degrees of equivalence. The degrees of equivalence between each equivalent activity measured in the SIR and the KCRV have been calculated and the results are given in the form of a table for the remaining two NMIs in the BIPM.RI(II)-K1.Zn-65 comparison and the 17 other participants in the CCRI(II)-K2.Zn-65 comparison. A graphical presentation is also given. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

In 2010, the Laboratoire National de M?trologie et d'Essais?Laboratoire National Henri Becquerel (LNE?LNHB) submitted one sample of known activity of 207Bi to the International Reference System for activity comparison at the Bureau International des Poids et Mesures, with comparison identifier BIPM.RI(II)-K1.Bi-207. The value of the activity submitted was about 180 kBq. There is now one result in the BIPM.RI(II)-K1.Bi-207 comparison. The key comparison reference value (KCRV) has been evaluated for the first time using the LNE?LNHB result and a PTB result dating 1982. The degree of equivalence between the LNE?LNHB equivalent activity measured in the SIR and the KCRV has been calculated and is reported. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

The PTB submitted directly to the SIR one ampoule of 166mHo prepared from a dilution of the solution distributed to four laboratories participating in the EURAMET.RI(II)-K2.Ho-166m comparison in 2013. No attempt to evaluate a new KCRV has been made and the usual procedure was applied to link the results of the comparison to the usual SIR entries through the PTB. One NMI used this K2 comparison to update its previous degree of equivalence which is older than 20 years. The degrees of equivalence between each equivalent activity measured in the International Reference System (SIR) and the KCRV have been calculated and the results are given in the form of a table for the four remaining laboratories in the BIPM.RI(II)-K1.Ho166m comparison, the six laboratories in the regional comparison APMP.RI(II)-K2.Ho166m and the four laboratories in the regional EURAMET.RI(II)-K2.Ho-166m comparison. A graphical presentation is also given. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Since 1975, ten laboratories have submitted 27 samples of known activity of 85Sr to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Sr-85. The values of the activity submitted were between about 0.2 MBq and 19 MBq. The key comparison reference value (KCRV) has been recalculated to include the primary standardization result for the POLATOM, Poland. There are now four results in the BIPM.RI(II)-K1.Sr-85 comparison. The degrees of equivalence between each equivalent activity measured in the SIR and the updated KCRV have been calculated and the results are given in the form of a table. A graphical presentation is also given. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Since 2009, three national metrology institutes (NMI) have submitted three samples of known activity of 133Ba to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Ba-133, to update their earlier result dating more than 15 years ago. The values of the activity submitted were between about 2 MBq and 3 MBq. There are now nine results in the BIPM.RI(II)-K1.Ba-133 comparison. The degrees of equivalence between each equivalent activity measured in the SIR and the key comparison reference value (KCRV) have been calculated and the results are given in the form of a table. A graphical presentation is also given. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Detailed uncertainty reporting is imperative for proficiency tests and comparison exercises because uncertainties need to be comparable and trusted by all the participants. Even though participants do their best to follow the Guide to the Expression of Uncertainty in Measurement, ambiguities and divergences about uncertainty evaluation remain. Consequently, to analyze the situation, the CCRI (II) Uncertainties Working Group proposed a comparison exercise (CCRI(II)-S7) about the uncertainty evaluation of a relatively simple primary activity measurement: the standardization of a 60Co source by coincidence counting. To be able to understand how various NMIs calculate coincidence counting uncertainties, our study focused on two of the dominant uncertainty components commonly quoted for 4πβ-γ coincidence counting in the International Reference System (SIR) submissions and Key Comparison exercises: efficiency-extrapolation and weighing. Participants from twelve different laboratories were sent the same set of measurement data from the analysis of a 60Co solution standardized at the National Physical Laboratory (NPL). Our study demonstrated the extent of the different interpretations of the uncertainty components. Some factors causing large discrepancies were isolated and are discussed. Further studies of other techniques using a similar approach would be beneficial for the metrology community. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Three new participants in the BIPM.RI(II)-K1.Eu-152 comparison have been added to the previous results and this has produced a revised value for the key comparison reference value (KCRV), calculated using the power-moderated weighted mean. A link has been made to the COOMET.RI(II)-K2.Eu-152 comparison held in 2010 through the VNIIM who participated in both comparisons. Three National Metrology Institutes (NMIs) used the K1 or K2 comparisons to update their degree of equivalence. The degrees of equivalence between each equivalent activity measured in the International Reference System (SIR) and the KCRV have been calculated and the results are given in the form of a table for four NMIs in the BIPM.RI(II)-K1.Eu-152 comparison, three participants in the COOMET.RI(II)-K2.Eu-152 comparison and the 18 other participants in the previous CCRI(II)-K2.Eu-152 comparison. A graphical presentation is also given. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Two new participations in the comparison BIPM.RI(II)-K1.Lu-177 have been added to the previous results and this has produced a revised value for the key comparison reference value (KCRV), calculated using the power-moderated weighted mean. A link has been made to the comparison CCRI(II)-K2.Lu-177 held in 2009 through the NPL and IRMM who participated in both comparisons. Two NMIs used the K2 comparison to update their degree of equivalence. The degrees of equivalence between each equivalent activity measured in the International Reference System (SIR) and the KCRV have been calculated and the results are given in the form of a table for the remaining two NMIs in the comparison BIPM.RI(II)-K1.Lu-177 and the nine other participants in the comparison CCRI(II)-K2.Lu-177. A graphical presentation is also given. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Three new participations in the BIPM.RI(II)-K1.I-131 comparison have been added to the previous results and this has produced a revised value for the key comparison reference value (KCRV), calculated using the power-moderated weighted mean. A link has been made to the APMP.RI(II)-K2.I-131 comparison held in 2009 through the NMIJ who participated in both comparisons. Three national metrology institutes (NMIs) used the Asia Pacific Metrology Programme (APMP) comparison to update their degree of equivalence. The degrees of equivalence between each equivalent activity measured in the International Reference System (SIR) and the KCRV have been calculated and the results are given in the form of a table for twelve NMIs in the BIPM.RI(II)-K1.I-131 comparison and five other participants in the APMP.RI(II)-K2.I-131 comparison. A graphical presentation is also given. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Since 2009, four national metrology institutes (NMI) have submitted four samples of known activity of 64Cu to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Cu-64. The values of the activity submitted were between about 3 MBq and 260 MBq. There are now five results in the BIPM.RI(II)-K1.Cu-64 comparison. A key comparison reference value (KCRV) has been calculated for the first time for this nuclide. The degrees of equivalence between each equivalent activity measured in the SIR and the KCRV have been calculated and the results are given in the form of a table. A graphical presentation is also given. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Purine nucleotide pyrophosphotransferase was purified to apparent homogeneity from a culture filtrate of Streptomyces morookaensis. It is a monomeric protein with a molecular weight of 24 000-25 000, and its isoelectric point is 6.9. The enzyme synthesizes purine nucleoside 5'-phosphate (mono, di, or tri) 3'-diphosphates such as pppApp, ppApp, pApp, pppGpp, ppGpp and pppIpp by transferring a pyrophosphoryl group from the 5'-position of ATP, dATP and ppApp to the 3'-position of purine nucleotides. The purified enzyme catalysed the formation of 435 mumol of pppApp and 620 mumol of pppGpp from ATP and GTP per min mg protein under the standard conditions. The enzyme requires absolutely a divalent cation for activity, and optimum pH for the enzyme activity lay above 10 for Mg2+, for Co2+ and Zn2+ from 9 to 9.5, and for Fe2+ from 7.5 to 8. The following Michaelis constants were determined: AMP, 2.78 mM; ADP, 3.23 mM; GMP, 0.89 mM; GDP, 0.46 mM and GTP, 1.54 mM, in the case of ATP donor. The enzyme is inhibited by guanine, guanosine, dGDP, dGTP, N-bromosuccinimide, iodacetate, sodium borate and mercuric acetate.

Since 2007, four national metrology institutes (NMI) have submitted four samples of known activity of 137Cs to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Cs-137. The values of the activity submitted were between about 1.4 MBq and 3.6 MBq. The results for the IFIN-HH, Romania, the NMISA, South Africa and the BEV, Austria, replace their earlier results in the key comparison database (KCDB). There are now fourteen results in the BIPM.RI(II)-K1.Cs-137 comparison to which three results of the COOMET.RI(II)-K2.Cs-137 are linked through the VNIIM, Russia, who participated in both comparisons. The degrees of equivalence between each equivalent activity measured in the SIR and the revised key comparison reference value (KCRV) have been calculated and the results are given in the form of a table and a graph, together with those of the previous participants. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

In 2008 and 2010, the Institutul de Fizica si Inginerie Nucleara–Horia Hulubei (IFIN–HH) and the National Institute of Standards and Technology (NIST) submitted samples of known activity of 57Co to the International Reference System (SIR). The values of the activity submitted were about 3.3 MBq and 125 MBq respectively. The new key comparison results have replaced the previous result for the USA and incorporate a first result for Romania. These new results, together with a recent re-evaluation of the half-life of 57Co have enabled a re-evaluation of the key comparison reference value. The degrees of equivalence in the key comparison database now contain twelve updated results for the comparison, identifier BIPM.RI(II)-K1.Co-57. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI Section II, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

In 2007, the Laboratoire national de metrologie et d'essais–Laboratoire national Henri Becquerel (LNE–LNHB), France submitted a sample of known activity of 222Rn to the International Reference System (SIR) for comparison. The value of the activity submitted was about 90 kBq. This key comparison result joins that of Switzerland and Germany in the key comparison database that now contains three results, identifier BIPM.RI(II)-K1.Rn-222. Consequently, the KCRV has been updated and the degrees of equivalence with the KCRV have been evaluated. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI Section II, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

In 2007, the Laboratoire national de metrologie et d'essais–Laboratoire national Henri Becquerel (LNE–LNHB), France submitted a sample of known activity of 124Sb to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM). The activity was about 5.3 MBq. The key comparison reference value (KCRV) has been recalculated to include this new value and the degrees of equivalence between each equivalent activity for the three participants measured in the SIR and the KCRV are presented in a table and graphically. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI Section II, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

In 2008, to update their previous result of 1999, the Physikalisch-Technische Bundesanstalt (PTB) submitted a new sample of 88Y with an activity of about 3.8 MBq to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM). This comparison has the identifier BIPM.RI(II)-K1.Y-88. The degree of equivalence between the equivalent activity measured in the SIR for the new PTB sample and the updated key comparison reference value (KCRV) has been calculated, as have the degrees of equivalence with each of the other participants. The results are given in the form of a matrix and a graphical presentation is also given. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI Section II, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

In 2006, to update their previous result of 1992, the LNE–LNHB submitted a new sample of 75Se with an activity of about 2.2 MBq to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM). This comparison has the identifier BIPM.RI(II)-K1.Se-75. The degree of equivalence between the equivalent activity measured in the SIR for the new LNE–LNHB sample and the updated key comparison reference value (KCRV) has been calculated, as have the degrees of equivalence with each of the other participants. The results are given in the form of a matrix and a graphical presentation is also given. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI Section II, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

The recent results of activity measurements of the radionuclide 139Ce by the PTB, Germany and the BEV, Austria have been included in the BIPM key comparison database through their participation in the International Reference System (SIR) for activity comparison in the BIPM.RI(II)-K1.Ce-139 comparison at the Bureau International des Poids et Mesures. The activities were about 4 MBq and 0.5 MBq, respectively. The degrees of equivalence between each equivalent activity measured in the SIR and the updated KCRV have been calculated and the results are given in the form of a table and graph, together with those of the previous participants. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI Section II, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

In 2006, the Cesk? Metrologick? Institut/Czech Metrological Institute ? Inspectorate for Ionizing Radiation (CMI-IIR) submitted an ampoule of known activity of 56Co to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures. The activity was about 6.7 MBq. The degrees of equivalence between each of the four national metrology institute results now measured in the SIR and the re-evaluated key comparison reference value (KCRV) have been calculated and the results are given in the form of a matrix. A graphical presentation is also given. The comparison identifier is BIPM.RI(II)-K1.Co-56. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI Section II, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

In 2006, the Laboratoire national de m?trologie et d'essais?Laboratoire national Henri Becquerel (LNE?LNHB) submitted a sample of known activity of 111In to the International Reference System (SIR). The value of the activity submitted was about 14 MBq. This provides a new result for France in the matrix of degrees of equivalence in the key comparison database that enables them to maintain their degrees of equivalence for this radionuclide. The key comparison reference value has been re-evaluated and the comparison, identifier BIPM.RI(II)-K1.In-111, now contains five valid results. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI Section II, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Since 2006, the Institutul de Fizica si Inginerie Nucleara ? 'Horia Hulubei' (Romania), and the National Institute of Standards and Technology (USA) and the Bundesamt f?r Eich- und Vermessungswesen (Austria) have each submitted samples of known activity of 60Co to the International Reference System (SIR). The values of the activity submitted were between 180 kBq and 3.1 MBq. The key comparison results now include updated results for these three national metrology institutes with the identifier BIPM.RI(II)-K1.Co-60. The key comparison reference value has been re-evaluated following the recommendations of the CCRI(II) and the matrix of degrees of equivalence in the key comparison database now contains nineteen results as some very early results have now been excluded, identifier BIPM.RI(II)-K1.Co-60. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI Section II, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Since 1976, twelve national metrology institutes (NMIs) have submitted 29 samples of known activity of 22Na to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM). The activities ranged from about 300 kBq to 20 MBq. The degrees of equivalence between each equivalent activity measured in the SIR and the key comparison reference value (KCRV) have been calculated and the results are given in the form of a matrix for nine NMIs. A graphical presentation is also given of this BIPM.RI(II)-K1.Na-22 comparison. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI Section II, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

In 2007 and 2008 respectively, the Laboratoire national de metrologie et d'essais–Laboratoire national Henri Becquerel (LNE–LNHB), France and the National Physical Laboratory (NPL), UK, submitted ampoules with between 10 MBq and 130 MBq activity of 99mTc to the International Reference System (SIR), to update their results in the BIPM.RI(II)-K1.Tc-99m comparison. Together with the four other national metrology institutes (NMI) that are participants, thirteen samples have been submitted since 1983. The key comparison reference value (KCRV) has been recalculated to include the latest primary results of the PTB and the LNE–LNHB as this makes the evaluation more robust. The degrees of equivalence between each equivalent activity measured in the SIR are given in the form of a matrix for all six NMIs. A graphical presentation is also given. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI Section II, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

In 2006, two national metrology institutes (NMI) submitted samples of known activity of 51Cr solution to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM). Consequently, 28 samples have been submitted since 1977, from nine NMI and three other laboratories. The activities ranged from about 3 MBq to 90 MBq. The key comparison reference value (KCRV) has been updated and the degrees of equivalence between each equivalent activity measured in the SIR and the KCRV have been calculated. The results are given in the form of a matrix for eight laboratories to which the APMP.RI(II)-K2.Cr-51 results have been added. A graphical presentation is also given. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI Section II, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

The IRA and the NPL have submitted ampoules of 166Hom to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures, thus becoming the third and fourth participants since 1989. The five samples of known activity of 166Hom now recorded in the SIR have activities between about 70 kBq and 500 kBq. The new results have enabled a re-evaluation of the key comparison reference value, and the degrees of equivalence between each equivalent activity measured in the SIR and the key comparison reference value (KCRV) have been calculated. The results are given in the form of a matrix for these four NMIs together with the recalculated degrees of equivalence of an APMP regional comparison held in 2000, comparison identifier APMP.RI(II)-K2.Ho-166m for six other NMIs. A graphical presentation is also given. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI Section II, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Since 2004, the National Metrology Institute of Japan (NMIJ) and the Physikalisch-Technische Bundesanstalt (PTB) have submitted samples of known activity of 57 Co to the International Reference System (SIR). The values of the activity submitted were about 1.8 MBq and 1.3 MBq respectively. These key comparison results have replaced the previous results for Japan and Germany in the matrix of degrees of equivalence in the key comparison database that contains fourteen results, identifier BIPM.RI(II)K1.Co-57.

In 2006, the Laboratoire national de metrologie et d'essais–Laboratoire national Henri Becquerel (LNE–LNHB), France, the National Physical Laboratory (NPL), UK and the Magyar Kereskedelmi Engedelyezesi Hivatal (MKEH), Hungary submitted samples of known activity of 54Mn to the International Reference System (SIR). The range of the activities submitted was from 480 kBq to 1530 kBq. The key comparison results for these three national metrology institutes (NMIs) have replaced their previous results in the matrix of degrees of equivalence in the key comparison database that contains eleven results, identifier BIPM.RI(II)-K1.Mn-54. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCRI Section II, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Since 2005, the Institutul de Fizica si Inginerie Nucleara–"Horia Hulubei" (IFIN-HH) of Romania and the National Metrology Institute of Japan (NMIJ) have each submitted samples of known activity of 133Ba to the International Reference System (SIR). The values of the activity submitted were about 1.4 MBq and 6.6 MBq. The IFIN result is their first contribution to the SIR for this radionuclide and for the NMIJ this key comparison result has replaced their earlier result dating from 1986. Each of these two new results has contributed to the updating of the KCRV for this radionuclide and is included in the matrix of degrees of equivalence in the key comparison database that now contains nine results for the comparison identified as BIPM.RI(II)-K1.Ba-133.Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCRI Section II, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).