CMCs and the BIPM Key Comparison Database

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CMCs and the BIPM Key Comparison Database

• Raul Fernando Solís Betancur
• rsolis_at_cenamep.org.pa
• 2015

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CIPM MRA

• Is the International Committee for Weights and
  Measures Mutual Recognition Arrangement.
• Is the framework through which National Metrology
  Institutes demonstrate the international
  equivalence of their measurement standards and
  the calibration and measurement certificates they
  issue.
• The CMC is the final product of all work in the
  CIPM MRA.

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Bureau International des Poids et Mesures

• International organization that resides in Paris,
  France.
• Coordinate the international metrology activities
  like comparisons, the units, the measurement
  capabilities, etc.
• Keeps a database of all comparison, calibration
  and measurement capabilities and provides
  worldwide access to the results.

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The BIPM Key Comparison Data Base

• Containing Appendices A, B, C and D of the CIPM
  MRA.
• Appendix A Participants in the CIPM MRA.
• Appendix B Key and supplementary comparisons.
• Appendix C Calibration and Measurement
  Capabilities CMCs.
• Appendix D List of key comparisons.

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Comparisons (I)

• They are the best way to show the level of your
  measurement skill.
• You need to participate in almost one comparison
  to validate yours capabilities and to include
  your CMC in the database.
• Under the CIPM MRA, the comparison can be Key or
  supplementary.
• The result are published in the Appendix B.

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Comparison (II)

• CIPM Key Comparison
• Comparison between NMIs with the highest level of
  skills in the measurement or the unit
  realization.
• The result of the comparison is a reference value
  of the quantity.
• MRO Key Comparison
• Comparison between NMIs in a RMO when one or more
  of the participants are in a CIPM Key comparison.
• Dont change the reference value obtained in the
  CIPM Key comparison.

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Comparison (III)

• Supplementary Comparison Is the comparison that
  helps link the NMI capabilities with the
  reference values (bilateral, pilots experiments,
  etc.).
• All of the participants of all comparison must be
  signatory of the MRA.
• If one of the participants isn't a MRA signatory,
  the comparison is only valid if you dont include
  his data in the comparison result.

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Comparison (IV)
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Comparison (V)

• The Universal Time Coordinated is our reference
  value (Key comparison CCTF-K001.UTC, started
  since 1977 and still ongoing).
• The Circular T is the official document that
  reports the key comparison results.
• The UTCr is a rapid solution for the laboratories
  that seek to steer their definitions close to the
  UTC.

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Circular T
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UTCr results
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SIM comparisons (I)

• The Time Frequency Network is an pilot
  experiment that acts like a regional comparison.
• SIMTFN is a method that allow bilateral
  comparison between the TF Key Comparison
  participants and the rest of the laboratories.
• The objective of this comparison is the increase
  of the calibration capabilities of all TF
  laboratories in our region.
• The results are published every hour in the SIMTF
  webpage.

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SIM comparisons (II)
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SIM comparisons (III)
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Calibration and Measurement Capability (I)

• The MRA seeks to bring equivalence in all the
  measurements in the world.
• The only way to ensure that this happens is to
  normalize our way to measure and express the
  results.
• The Calibration and Measurement Capability (CMC)
  is the final product of these process.

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Calibration and Measurement Capability (II)

• The BIPM has a list of CMC for the 9 metrology
  areas.
• Every NMI that is part of the MRA and can provide
  enough evidence of their measurement skills in
  these areas can register their capabilities in
  the Appendix C.
• The SIM region has only 6 laboratories with CMC
  in the TF metrology area (approximately 45 in
  total around the world, December 2014).

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Calibration and Measurement Capability (III)

• For the declaration of your CMC you need
• To be a signatory of the MRA (member or associate
  state).
• A peer review in the service that you want to
  publish (is better if the evaluator is from other
  NMI with a CMC or a good reputation in the
  metrology area).
• To fulfill the quality assessment under the
  ISO/IEC 17025.

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Calibration and Measurement Capability (IV)

• For the approval of your CMC you need
• A comparison with some NMI with link to the UTC.
• The approval of your Quality System from the SIM
  QSTF.
• The approval of your technical capabilities from
  all RMOs.
• Fulfilling all these points grants the
  incorporation of your CMC in the Appendix C.

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Calibration and Measurement Capability (V)

• The CMC only had a vitality of 5 years. After
  that you need to perform the same exercise to
  maintain yours CMC.
• The values can be updated for better or for
  worse.
• This depend of the actual situation in your
  laboratory (changes in your equipment,
  environmental condition, calibration methods,
  etc.).

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Calibration and Measurement Capability (VI)

• To demonstrate vitality you need to show record
  of your work by
• Comparisons.
• Publications of your work (journals, conference
  proceedings, etc.).
• Participation in the Working Groups.
• Advisories / third party audits.
• Trainings.
• Continuous improvement through RD.

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Classification of services in Time and Frequency

• In the TF metrology area, the measurement
  capabilities are divided in three branches
  (version 1.0 of December 2002)
• Time scale difference synchronization with UTC
  or UTC(k).
• Frequency frequency difference.
• Time interval duration of events.

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Branch 1 Time scale difference

• 1.1. Local clock
• 1.1.1. Local clock vs. UTC(NMI)
• 1.1.2. Local clock vs. UTC
• 1.2. Remote clocks
• 1.2.1. Remote clock vs. UTC(NMI)
• 1.2.2. Remote clock vs. UTC

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Branch 2 Frequency

• 2.1. Standard frequency source
• 2.1.1. Local frequency standard
• 2.1.2. Remote frequency standard
• 2.2. General frequency source
• 2.2.1. General frequency source
• 2.3. Frequency meter
• 2.3.1. Frequency counter
• 2.3.2. Frequency meter

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Branch 3 Time interval (I)

• 3.1. Period source
• 3.1.1. Period source
• 3.2 Time Interval source
• 3.2.1. Rise/fall time source
• 3.2.2. Pulse width source
• 3.2.3. Time difference source
• 3.2.4. Delay source

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Branch 3Time interval (II)

• 3.3. Period meter
• 3.3.1. Period meter
• 3.4 Time Interval meter
• 3.4.1. Rise/fall time meter
• 3.4.2. Pulse width meter
• 3.4.3. Time difference meter
• 3.4.4. Delay meter

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The CMC sheet (I)
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The CMC sheet (II)
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Calibration or Measurement Service
Calibration or Measurement Service Calibration or Measurement Service Calibration or Measurement Service
Quantity/ Class Instrument or Artifact Instrument Type or Method
     
     
     
     
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Calibration or Measurement Service

• Quantity / Class basically the branch that you
  want to measure (frequency, time interval or time
  scale difference).
• Instrument or Artifact Is the device under test
  but in terms of the sub points of the branch
  (1.x., 2.x., 3.x., 1.x.x., 2.x.x and 3.x.x.).
• Instrument Type or Method How you perform the
  comparison or the data acquisition (direct
  frequency measurement, direct comparison against
  UTC(k), etc).

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Measurement Level or Range
Measurand Level or Range Measurand Level or Range Measurand Level or Range
Minimum value Maximum value Units
     
     
     
     
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Measurement Level or Range

• Minimum Value the lower number that you can
  acquire in your measurement range.
• Maximum value the highest number that you can
  acquire in you measurement range.
• Units the units of the values that you acquire.

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Measurement Conditions/Independent Variable
Measurement Conditions/Independent Variable Measurement Conditions/Independent Variable
Parameter Specifications
   
   
   
   
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Measurement Conditions/Independent Variable

• Parameter every variable or condition that limit
  your measurement capability (gate time,
  measurement time, averaging time, signal
  amplitude, line impedance, slew rate, etc.).
• Specification the limits of the parameters in
  yours measurement.

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Expanded Uncertainty
Expanded Uncertainty Expanded Uncertainty Expanded Uncertainty Expanded Uncertainty Expanded Uncertainty
Value Units Coverage Factor Level of Confidence Is the expanded uncertainty a relative one?
         
         
         
         
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Expanded Uncertainty

• Value the uncertaintys value that you want to
  declare.
• Units the units of your declared uncertainty.
• Coverage factor the value that you use to expand
  your standard uncertainty (usually k2).
• Level of Confidence usually is 95.
• Is the expanded uncertainty a relative one?
  Indicates if the value of uncertainty has turned
  relative.

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Reference Standard used in calibration
Reference Standard used in calibration Reference Standard used in calibration
Standard Source of traceability
   
   
   
   
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Reference Standard used in calibration

• Standard your time and frequency reference.
• Source of Traceability The INM is the one that
  has traceability to the time unit.

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List of Comparisons supporting this
measurement/calibration service
List of Comparisons supporting this measurement / calibration service
 
 
 
 
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List of Comparisons supporting this
measurement/calibration service

• List of Comparisons supporting this measurement /
  calibration service The comparison that you have
  participated in to show your measurement
  capabilities to another NMI.

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Comments to be published via the web page
Comments to be published via the web page
 
 
 
 
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Comments to be published via the web page

• Comments to be published via the web page
  information about the calibration, uncertainty,
  and when the CMC is published.

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Administration
Administration Administration Administration Administration Administration
NMI Service Identifier Service Category NMI Review Status Review Comments
         
         
         
         
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Administration

• NMI Service Identifier The internal ID for the
  NMI to identify this service.
• Service Category The CMC service identifier.
• NMI The National Metrology Institute or
  delegated metrology institute that publishes the
  CMC.
• Review Status the actual situation of the
  verification of your CMC.
• Review Comments aditional information about the
  verification process.

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Example of filling a CMC Sheet
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Example of filling a CMC Sheet
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How the world see your CMC
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Discussion

• What is the individual need of the NMI to
  register your CMC in the KCDB?.
• The need for training and technical advising.
• You can start with a low level capability
  calibration services like stopwatches, frequency
  meters or optical tachometers (rubidium
  oscillator is enough for this).
• Do you need to increase your measurement
  capability confidence? Do you need a pilot
  comparison?
• Tell us what you think.

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Useful links

• SIM TFWG page http//tf.nist.gov/sim/
• BIPM KCDB page http//kcdb.bipm.org/
• CIPM MRA page http//www.bipm.org/en/cipm-mra/
• BIPM TF server page http//www.bipm.org/en/bipm-
  services/timescales/time-ftp.html
• NIST uncertainty of measurements result page
  http//physics.nist.gov/cuu/Uncertainty/index.html

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• Thanks!