JBASV8N2A42- Dosimetry Characterization of Unknown Dye Polyvinyl Alcohol Films

Journal of Basic and Applied Sciences - Volume 8 Number 2

Dosimetry Characterization of Unknown Dye Polyvinyl Alcohol Films

Muhammad Attique Khan Shahid, Noureen Kousar, Naseem Akhtar, Taqmeem Hussain, Mariam Saeed Awan, Arfa Mubashir, Bushra Bashir and Asif Javed

http://dx.doi.org/10.6000/1927-5129.2012.08.02.42

Abstract: In the present study chemical dosimeters having aqueous solutions of crystal violet commercial dye were irradiated by Co⁶⁰ γ source in the range (0-120)KGy. The standard aqueous solutions were scanned by UV/VIS spectrophotometer for the determination of maximum wave length (λ_max) which was found to be 591nm at this value maximum absorbance was found to be 3.5; it was also observed that with increase in dose, absorbance decreases correspondingly. At this value, the absorbance (A) of irradiated samples was measured in UV region. The plot between concentration C and A gave approximate linear relationship and hence verified Beer’s Law which proved that these dye solutions can satisfactorily be used as the dye dosimeters in 0-120kGy gamma dose range.

Keywords: Aqueous solutions, the crystal violet dye, dosimetry, gamma irradiation, Optical density (OD), decolouration.

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The Effect of Grain Size on Radon Exhalation Rate in Soil Samples of Dera Ismail Khan in Pakistan

Tabassum Nasir and Nisar Ahmad

http://dx.doi.org/10.6000/1927-5129.2012.08.02.29

Abstract: Radon concentration and its exhalation rate has been measured from twenty five soil samples collected from seven different locations of Dera Ismail Khan, in the north west of Pakistan. These samples were crushed after drying and passed through sieves with different sizes of pores to get three grain sizes, £0.595 mm, 0.595-2.00 mm and 2.00-4.00 mm of soil. CR-39 based NRPB (National Radiological Protection Board) radon dosimeters have been used to measure the radon concentration and exhalation rates. The maximum average value of radon exhalation rate has found to be: (3.57±0.38) Bq m^-2 hr^-1 in the samples having grain size 2.00-4.00 mm and the minimum as: (2.21±0.26) Bq m^-2 hr^-1, in the samples with grain size £ 0.0595 mm. This indicates that the radon exhalation rate increases with the grain size. The maximum average value of radon exhalation rate has been found in samples collected from river side where soil texture is silty clay loam. The obtained values of radon exhalation rate for all the samples are well below the world average value of 57.60 Bq m^-2 hr^-1.

Keywords: Radon concentration, Radon exhalation rate, grain size, soil texture.