as
the exposure rate region used with e set of Victorsen rusters calibrated
et Rational Bureeu of Standards (8S) in Merch 1956,
GommeCalihrton, There were no
sources svailable for direct gemme-radistion calibration uw to the maximm
ranges of the initial game instruments,
Becsuse of this leck, scintillae-
tion detectors ware used, thereby enebling calibration with a light source.
In prectice, the instrussnts were directly calibrated by the use of the
200-curie Co™ source in the field and a Van de Graeff generator in the
Laboratory to the limit of the available radiation rates.
The calibration
was then extended to the maximum range through the use of a light calibre-
tion, which was normalized to the radiation calibration,
The light calibeator consists of a Light source filtered to provite
a bean having approximately the sane spectral quality as the Light output
of the scintillator, and a series of neutral density filters tlei vary
the light output in known discrete steps.
Errors due te the direct
response of the circuit elements to gamma radiation are introduced into
the calibrations however, these errors have been shown to be small in the
ranges where the light and radiation calibrations overlap. There are Bo
reaeons why the relative error should increase beyond the renge of duel
calibration.
ST, LOoOviS FRC
2.3 READOUT ERROR AND ACCURACY OF THE GUSTAVE AND CONRAD SYSTEMS
In general, the output of the. Gustave and Conrad detectors may be
given as:
r= Kt”
(2,4)