The water absorbed dose calorimeter can be established as a primary st
andard for the quantity, water absorbed dose, if the heat defect probl
em can be solved. The method chosen is an experimental absolute determ
ination using a total absorption calorimeter for high energy electrons
, so that the heat defect need not necessarily be zero, which is a cru
cial condition, but only stable. First results, including investigatio
ns of the stability of the heat defect for various aqueous solutions,
are presented.