EXPANSION OF THE MASS SCALE FOR A RANGE LESS-THAN 1 MG

Mass differences in steps of 0,01 mg and 0,1 mg have been realized using special new mass standards. These standards have been adjusted to their nominal values within 2 mug and they have been calibrated with the PTBs primary standards with uncertainties of less than 0,2 mug. When the linearities of two microbalances of different manufacturers were tested in steps of 0,1 mg and 0,01 mg at different charges, the deviations were less than 1,2 mug. These new mass standards extend the PTBs set of primary standards by the range between 0,01 mg and 1 mg and make verifications of linearity and unbiased indication of balances in the range below 1 mg possible.