CCRI(III)-K9.Cf-252.2016
MEASURAND : Neutron source emission rate
SOURCE : 252Cf(sp.f.)
Degrees of equivalence represented by Di = (xI - xR) and its expanded uncertainty Ui at a 95 % level of confidence, both expressed in (107 s-1).
CCRI(III)-K9.Cf-252.2016
MEASURAND : Neutron source emission rate
SOURCE : 252Cf(sp.f.)
Degrees of equivalence represented by Di = (xI - xR) and its expanded uncertainty Ui at a 95 % level of confidence, both expressed in (107 s-1).
| LABi | Di | Uneg,i | Upos,i | |
|---|---|---|---|---|
×107 s-1 |
×107 s-1 |
×107 s-1 |
||
| CMI | -0.0002 | 0.0080 | ||
| KRISS | 0.0060 | 0.0207 | ||
| LNE-LNHB | -0.0168 | 0.0325 | ||
| LNMRI/IRD | 0.0136 | 0.0182 | ||
| NIM | 0.0007 | 0.0180 | ||
| NIST | -0.0069 | 0.0213 | ||
| NMIJ | -0.0051 | 0.0400 | ||
| NPL | -0.0084 | 0.0117 | ||
| NRC | 0.0309 | 0.0396 | ||
| VNIIM | 0.0021 | 0.0144 |
| Metrology area, Sub-field | Ionizing Radiation, Section III (Neutron Measurements) |
| Description | Emmission rate |
| Time of measurements | 2016 - 2019 |
| Status | Approved for equivalence |
| Final Reports of the comparisons | |
| References | |
| Measurand | Neutron emission rate into 4π sr (approx 1.2E7 neutrons per second in 2015) |
| Transfer device | Cf-252 spontaneous fission neutron source in special form capsule, serial number 51227B |
| Comparison type | Key Comparison |
| Consultative Committee | CCRI (Consultative Committee for Ionizing Radiation) |
| Conducted by | CCRI (Consultative Committee for Ionizing Radiation) |
| Comments | Results published on 05 August 2024 |
| Pilot institute |
NPL
National Physical Laboratory United Kingdom |
| Contact person | Neil Roberts +44 (0) 20 8943 6869 |
| Pilot laboratory | |
|---|---|
| NPL |
National Physical Laboratory, United Kingdom, EURAMET |
| CMI |
Czech Metrology Institute, Czechia, EURAMET |
| KRISS |
Korea Research Institute of Standards and Science, Korea, Republic of, APMP |
| LNE-LNHB |
Commissariat à l'énergie atomique / Laboratoire National Henri Becquerel, France, EURAMET |
| LNMRI/IRD |
Laboratorio Nacional de Metrologia das Radiacoes Ionizantes, IRD, Brazil, SIM |
| NIM |
National Institute of Metrology, China, APMP |
| NIST |
National Institute of Standards and Technology, United States, SIM |
| NMIJ AIST |
National Metrology Institute of Japan, Japan, APMP |
| NRC |
National Research Council, Canada, SIM |
| VNIIM |
D.I. Mendeleyev Institute for Metrology, Rosstandart, Russian Federation, COOMET |
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CCRI(III)-K9.Cf-252.2016
MEASURAND : Neutron source emission rate
SOURCE : 252Cf(sp.f.)
The key comparison reference value xR and its associated standard uncertainty uR is calculated from the weighted mean of the reported results excluding the results of NMIJ (See section 9.1 (Appendix A) of the CCRI(III)-K9.Cf-252.2016 Final report).
xR = 1.2550 × 107 s-1 uR = 0.0028 × 107 s-1
The degree of equivalence of laboratory i relative to the key comparison reference value xR is given by a pair of terms, both expressed in (107 s-1):
Di = (xi - xR) and its expanded uncertainty Ui at a 95 % level of confidence where Ui = 2 ui and ui = sqrt(ui2 - uR2) for participants included in the calculation of the KCRV and ui = sqrt(ui2 + uR2) for participants not included in the calculation of the KCRV (see section 9.1 (Appendix A) of the CCRI(III)-K9.Cf-252.2016).
CCRI(III)-K9.Cf-252.2016
MEASURAND : Neutron source emission rate
SOURCE : 252Cf(sp.f.)
xi measured mass fraction reported by laboratory i, Labi
Ui expanded uncertainty of xi at 95 % level of confidence where Ui = 2 ui
Emission rates corrected to 1st January 2016
| Labi | xi | Ui | |
| ×107 s-1 | ×107 s-1 | ||
| CMI | 1.2549 | 0.0098 | |
| KRISS | 1.2611 | 0.0215 | |
| LNE-LNHB | 1.2383 | 0.0329 | |
| LNMRI | 1.2687 | 0.0190 | |
| NIM | 1.2558 | 0.0189 | |
| NIST | 1.2481 | 0.0220 | |
| NMIJ | 1.2499 | 0.0396 | |
| NPL* | 1.2467 | 0.0130 | |
| NRC | 1.2860 | 0.0400 | |
| VNIIM** | 1.2572 | 0.0154 |
* The NPL value is from the 2016 measurement only
** The VNIIM value is a mean of the manganese bath and associated particle measurements
