Abstract
The suitability of
acetylene as a gas-phase radiation dosimeter has been studied. Yields were
obtained on an absolute basis, using ionization current dosimetry. Radiolysis
of acetylene produces two products, benzene and polymer. The yield of benzene
is dependent on dose, dose rate, presence of hydrogen or free radical
scavengers, and temperature, and is of no value for estimating dose. ��� For 60Co
γ irradiation at a dose rate of 4.1 x 1013 eV
cm-3 mmHg-1 hr-1 and acetylene pressure 500
mmHg (6.6x104 N m-2) at 30�C, G(-C2H2)
= 82.1�0.5. ��� 1-MeV electron
irradiation at a dose rate of 3.9 x 1016 eV
cm-3 mmHg-1 hr-1 gave a much lower yield, G(-C2H2)
= 55.0�1.9, believed to be due to a dose rate effect. G(-C2H2)
increased by about 67% when the temperature was increased from 25�C to 125-250�C.
��� Comparison with ethylene indicates the
latter is the more useful dosimeter, as the yields do not vary significantly
over a wide range of dose rates and temperatures.