Mass Unit Disseminated to Surrogated Laboratories Using the NIST Portable MassCalibration Package

摘要

Over a ten-year period, three mass calibration packages were circulated toselected laboratories by the Mass Group at NIST. Initially the objective was to determine if the NIST mass calibration service could be disseminated to qualified users via a 'do-it-yourself' package. However, it became obvious that the technique could be very useful in the training of personnel and the examination of laboratories. The first package of 1-kilogram artifacts was circulated to see what problems might arise in their calibration. The second package was designed to overcome the difficulties encountered and to ensure the quality of the next package. The third and final package incorporates improvements and demonstrates the method with the calibration of the California State primary mass standards from 1 kg to 1 mg. This report looks briefly at the entire project experience with comments about the pitfalls and benefits of calibrations by surrogate laboratories and other likely uses of the method.