Open AccessNote on weighings carried out on the NBS-2 balance
Author(s) -
Philippe Carré,
Richard Davis
Publication year - 1985
Publication title -
journal of research of the national bureau of standards
Language(s) - English
Resource type - Journals
eISSN - 2376-5259
pISSN - 0160-1741
DOI - 10.6028/jres.090.023
Subject(s) - kilogram , standard deviation , relative standard deviation , balance (ability) , variance (accounting) , standard uncertainty , systematic error , environmental science , measurement uncertainty , statistics , mathematics , computer science , accounting , body weight , medicine , physical medicine and rehabilitation , detection limit , business
The NBS-2 balance was designed and built at NBS and transferred to the BIPM in 1972. It is presently used for the comparison of national prototype kilograms with international standards. Excellent environmental conditions at the BIPM have resulted in a long-term standard deviation of 1 microgram (l× 10 -9 ) for a comparison of two 1-kilogram standards. With this remarkable precision, one has begun to observe and quantify systematic biases of less than 5 micrograms. The nature of these biases is presented as well as the remedy adopted to eliminate their influence on both the final measurement results and the variance assigned to those results.