1 Improvement of Mass Determination Using AT-1006 Comparator in NIS – Egypt

A major factor determining the uncertainty associated with the value of a standard mass at any level is the performance of the mass comparators employed at various levels in the traceability chain. Improvement in the uncertainty of mass standards is thus dependent on the research and developments of better mass comparators. The National Institute for Standard (NIS) Egypt was equipped in 1997 with Mettler AT-1006 comparator to compare masses in four positions. The comparator capacity from 50 to 1000 g is of particular interest, since this range is the range in which the comparisons against the national prototype kilogram are carried out. Controlling software has been adopted to work with the Mettler AT-1006 comparator for driving the balance to execute any comparison scheme. New climatic system for measuring the air density was established for Measuring the ambient parameters and combining them in the well-known BIPM 1990 formula enable measuring of the air density in the laboratory indirectly. The performances of the system were studied as well as an estimation of expanded standard uncertainty calculations were carried out. Improvement in the comparator performance after using the new control software has been achieved and the climatic system