J.RADIOANAL.NUCL.CHEM.,LETTERS 175 (3) 199-206 (1993) STABILITY OF RESPONSE OF THE FERROUS-CUPRIC SULFATE DOSIMETER AT DIFFERENT TEMPERATURES H.M. Khan, M. Anwar National Centre of Excellence in Physical Chemistry, University of Peshawar, Peshawar 25120~ Pakistan Received 10 November 1992 Accepted 20 November 1992 Aqueous solution of ferrous-cupric sulfate has been evaluated spectrophotometrically as radiation dosimeter and post-irradiation stability at different storage temperatures has been studied. The response curve drawn at a peak wavelength of 304 nm shows a linear response of up to 7 kGy. However, with proper calibration, the system can be used up to 14 kGy. At room temperature (ca. 25 ~ in the dark, the irradiated solution showed stable response up to about 12 h, followed by a small decrease in response up to 20 d. Post-irradiation storage at lower temperature (10 ~ shows no significant change in absorbance over a storage period of 6 d. However, for storage at higher tem- perature (40 ~ the dosimeter showed a stable response only up to a few hours and at longer storage times the response of the dosimeter increased. INTRODUCTION Aqueous solution of ferrous-cupric sulfate has been used as a modified ferrous sulfate (Fricke) dosimeter and its reaction mechanism has been studied thorough- 199 Elsevier Sequoia S. A., Lausanne Akad~mlai Kiad6, Budapest