ECOTEST DKG-21 Operating Manual page 66

5.2.7.5.2 Fix the dosimeter on the phantom as stated in 5.2.7.3 in the
УПГД-3Б carriage so that the mechanical center of the УПГД-3Б
collimator coincides with the mechanical center of the dosimeter's detector.
5.2.7.5.3 Prepare the dosimeter for DE measurement and place the
УПГД-3Б carriage together with the phantom and the dosimeter in the
position, where DER from the source with
H  = (80±10) µSv/h and at the same time switch on the stop-watch
( 10 )
p 0
and place the source into the collimator.
5.2.7.5.4 In the period of time (according to the stop-watch) expressed
in seconds and calculated by the formula t = 3600 + t д , where t д is the
period of time expressed in seconds used to place the source into the
collimator, take DE measurement result. Switch the dosimeter off
afterwards.
5.2.7.5.5 Calculate the limit of main relative permissible error of DE
measurement in percentage by the formula
137
64
Cs radionuclide is