MEASURAND : Thermal neutron fluence

Graph of equivalence

MEASURAND : Thermal neutron fluence

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

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

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CC comparison
Linked comparison
Metrology area, Sub-field Ionizing Radiation, Section III (Neutron Measurements)
Description Comparison of neutron fluence rate
Time of measurements 2006 - 2010
Status Approved for equivalence
Final Reports of the comparisons
Measurand Thermal neutron fluence rate: from 104 cm-2s-1 to 109 cm-2s-1
Parameters Thermal neutron
Transfer device Two SP9-counters with different He-3 fillings
Comparison type Key Comparison
Consultative Committee CCRI (Consultative Committee for Ionizing Radiation)
Conducted by CCRI (Consultative Committee for Ionizing Radiation)

This comparison was first registered into the BIPM KCDB under the identifier CCRI(III)-K8.B-10.
At its 15th meeting, in 2003, the Section III of the CCRI decided that the B-10 ionization chambers were too sensitive to environmental disturbances, and decided to use different well-characterized thermal neutron fields available at the NIST research reactor.
The comparison was then identified as CCRI(III)-K8.
The PTB took over the role of pilot laboratory in 2006.

Results published on 09 March 2015

Comparison of neutron fluence

Pilot institute PTB
Physikalisch-Technische Bundesanstalt
Contact person R. Nolte

+49 (0) 531 592 6420
First Name Last Name
wwww@ww.www +356719836 Institute 1 Institute 1 Khmelnitskiy
Pilot laboratory

Physikalisch-Technische Bundesanstalt, Germany, EURAMET


National Metrology Institute of Japan, Japan, APMP


National Physical Laboratory, United Kingdom, EURAMET

MEASURAND : Thermal neutron fluence

The key comparison reference value, xR, is taken as 1.

The degree of equivalence of each laboratory i 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 cm2/cm2. Ui = 2ui.
When required, the degree of equivalence between two laboratories i and j is given by a pair of terms: Dij = Di - Dj and Uij, its expanded uncertainty (k = 2), both expressed in cm2/cm2.
Pair-wise degrees of equivalence are given in Table 3 of the Final Report.

MEASURAND : Thermal neutron fluence

xi : measurement result obtained by laboratory i expressed as the mean ratio of measured instrument response by laboratory i to the reference instrument response
ui : combined standard uncertainty of xi

Measurements were performed between October 2006 and July 2010

 Lab i



 NMIJ 0.993 0.019
 NPL 0.918 0.025
 PTB 0.987 0.036