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BIPM.RI(II)-K1.Np-237 and EUROMET.RI(II)-K2.Np-237

MEASURAND : Equivalent activity of 237Np

Degrees of equivalence Di and expanded uncertainty Ui (k = 2) expressed in MBq

Red diamonds : participants in BIPM.RI(II)-K1.Np-237
Green triangles : participants in EUROMET.RI(II)-K2.Np-237

Note: the right-hand axis shows approximate relative values only.

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BIPM.RI(II)-K1.Np-237 and EUROMET.RI(II)-K2.Np-237

MEASURAND : Equivalent activity of 237Np

   
Lab iDiUi
 / MBq/ MBq
BIPM0.61.6
PTB-0.10.3
IRMM0.10.3
LNE-LNHB0.40.5
CIEMAT0.70.8
NPL-0.60.9
NRC-0.81.7

In green: participants in EUROMET.RI(II)-K2.Np-237

Results are presented under A4 printable format in Summary Results (.PDF file).

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Linked comparison
EUROMET.RI(II)-K2.Np-237
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Metrology area, Sub-field Ionizing Radiation, Section II (Measurement of Radionuclides)
Description Activity of radionuclide Np-237
Time of measurements 1997 - 2001
Status Approved for equivalence
Final Reports of the comparisons
NPL Report CIRM 43, 2001
Metrologia, 2007, 44, Tech. Suppl., 06002
Measurand Activity
Comparison type Key Comparison
Consultative Committee CCRI (Consultative Committee for Ionizing Radiation)
Conducted by EURAMET (European Association of National Metrology Institutes)
RMO Internal Identifier EUROMET Project No 416
Comments

EUROMET.RI(II)-K2.Np-237 results are linked to those of BIPM.RI(II)-K1.Np-237

BIPM.RI(II)-K1.Np-237 and EUROMET.RI(II)-K2.Np-237 results were published on 28 June 2007.

SIR equivalent activity of the radionuclide 237Np
Pilot institute NPL
National Physical Laboratory
United Kingdom
Contact person M.J. Woods

+44 (0) 20 8943 6425
First Name Last Name
wwww@ww.www +356719836 Institute 1 Institute 1 Khmelnitskiy
Pilot laboratory
NPL

National Physical Laboratory, United Kingdom, EURAMET

BIPM

Bureau International des Poids et Mesures, BIPM - International Organization, N/A

CIEMAT

Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas, Spain, EURAMET

NRC

National Research Council, Canada, SIM

PTB

Physikalisch-Technische Bundesanstalt, Germany, EURAMET

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BIPM.RI(II)-K1.Np-237 and EUROMET.RI(II)-K2.Np-237

MEASURAND : Equivalent activity of 237Np

  • Key comparison BIPM.RI(II)-K1.Np-237

Key comparison reference value: the SIR reference value for this radionuclide is xR = 74.85 MBq, with a standard uncertainty uR = 0.11 MBq (see section 4.1 of the Final Report).

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. With n the number of laboratories, when each laboratory has contributed to the computation of xR.

The degree of equivalence between two laboratories is given by a pair of terms:
Dij =(Di - Dj) = (xi - xj) and Uij, its expanded uncertainty (k = 2), both expressed in MBq. The approximation Uij ~ 2(ui2 + uj2)1/2 is used in the Matrix of equivalence.
  • Linking EUROMET.RI(II)-K2.Np-237 to BIPM.RI(II)-K1.Np-237

The value xi is the equivalent activity for laboratory i participant in EUROMET.RI(II)-K2.Np-237 having been normalized using the SIR measurements of the BIPM, PTB, and the IRMM as linking laboratories.

The degree of equivalence of laboratory i participant in EUROMET.RI(II)-K2.Np-237 with respect to the key comparison reference value is given by a pair of terms:
Di = (xi - xR) and Ui, its expanded uncertainty (k = 2), both expressed in MBq.
The approximation Ui = 2(ui2 + uR2)1/2 is used in the Matrix of equivalence.

The degree of equivalence between two laboratories i and j, one participant in BIPM.RI(II)-K1.Np-237 and one in EUROMET.RI(II)-K2.Np-237, or both participants in EUROMET.RI(II)-K2.Np-237, is given by a pair of terms expressed in MBq:
Dij = Di - Dj and Uij, its expanded uncertainty (k = 2), approximated by
Uij = 2(ui2 + uj2 - 2ful2)1/2 with ul being the standard uncertainty of the link when each laboratory is from EUROMET and f is the correlation coefficient.


These statements make it possible to extend the BIPM.RI(II)-K1.Np-237 matrix of equivalence to all participants in EUROMET.RI(II)-K2.Np-237.
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BIPM.RI(II)-K1.Np-237 and EUROMET.RI(II)-K2.Np-237

MEASURAND : Equivalent activity of 237Np

  • Key comparison BIPM.RI(II)-K1.Np-237

xi : result of measurement carried out in the SIR for the sample submitted by laboratory i
ui : combined standard uncertainty of xi

     Lab i xi
    / kBq    		 ui
    / kBq    		 Date of measurement
     BIPM 75440 790 12-06-1998
     PTB 74740 220 02-02-2006
     IRMM 74950 180 27-02-2007

    • Key comparison EUROMET.RI(II)-K2.Np-237

    xi : result of measurement carried out at laboratory i converted to the equivalent activity through the linking laboratories BIPM, PTB and the IRMM
    ui : combined standard uncertainty of xi

     Lab i xi
    / kBq    		 ui
    / kBq    		 Year of measurement
     LNE-LNHB 75210 230 1998
     CIEMAT 75510 380 1999
     NPL 74210 450 1998
     NRC 74060 820 1998