The temperature of the atomization surface at which the analyte signal/noise
(S/N) ratio reaches a value of 3 when the quantity of analyte in the atomizer is one hundred times the characteristic mass for peak high absorption.
PAC, 1992, 64, 253
(Nomenclature, symbols, units and their usage in spectrochemical analysis - XII. Terms related to electrothermal atomization (IUPAC Recommendations 1992))
on page 257
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997). XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8. doi:10.1351/goldbook