Documentation for Standard Tree JPG files

(April 5, 2001)

These files show the histories of gravimetric standards prepared by the HATS 
standards project.   The purpose of these figures is to show the various relationships 
between primary standards and their offspring.    Standards that are currently used to 
determine CMDL calibration scales associated with GC-ECD inctruments are shown in 
yellow. Standards that are known to be obsolete (low pressure or lost) 
are crossed out.   Standards prepared prior to 1988 are generally not included in these 
figures.   Data for obsolete standards may not be complete.   If anyone discovers a standard 
to be lost or otherwise no longer useful,  please let me (Brad) know and I will update these files.

For information on CMDL calibration scales and mixing ratios "assigned" to gravimetric standards
to create a consistent scale, see the [DATA] section on the HATS webpage.