A dose vs TL response calibration curve was established for the 220 deg. In the present studies, the sand separated from the sludge was used to estimate irradiation dose to sludge at Sludge Hygienisation Research Irradiator (SHRI), Vadodara, India. Recently, we have investigated the thermoluminescence (TL) properties of the sand, collected from the sewage sludge, after various extensive cleansing procedures. The response to gamma radiation shows negligible dose-rate dependence as long as the radiochromic sensor concentration in the PVA matrix is sufficiently high (> 6 % by weight). C, but displays a pronounced positive temperature dependence at higher temperatures. The variation of response with irradiation temperature is negligible over the temperature range -20 deg. The value of ΔA shows a gradual increase for the first 24 hours after irradiation but is stable thereafter. The radiochromic image has a relatively high spatial resolution and can be used to register dose distributions and beam profiles. The radiation response is approximately a linear function in terms of the increase in optical absorbance (ΔA) measured at λ max 552 nm wavelength versus absorbed dose (D) over the range 5 to 50 kGy. Upon irradiation with gamma rays or electron beams, a permanent image is produced with a broad absorption band in the visible spectrum. In the present development, the resulting flexible transparent film is readily stripped from the plate, with a thickness of 0.045 mm. Dosimeter films of this radiation sensor can be produced by dissolving polyvinyl alcohol (PVA) in a heated aqueous solution of the salt, and, upon cooling, by casting the solution on a horizontal glass plate. The final stage of the thesis describes the use of the new tool to develop ways in which imprecise or uncertain information can be presented to decision makers.The colourless radiochromic chloride salt of blue tetrazolium (BT 2+) is reduced radiolytically to the deep violet-coloured formazan. A prototype version of the tool has been created and this has been used to produce example results. This tool uses input from real-time atmospheric dispersion and weather prediction tools. An alternative improved approach to emergency response assessments is then outlined, which retains a simple and transparent assessment capability but which also indicates the imprecision associated with the results through incomplete knowledge. These are demonstrated to be factors relating to the release, arising from inevitable lack of knowledge in the early stages of an accident, and factors relating to meteorology and dispersion. The key parameters influencing assessment imprecision are identified. This has been done using both a simple Gaussian atmospheric dispersion model and also real-time weather data in combination with a complex atmospheric dispersion model. The imprecision typically associated with calculational endpoints is explored through a sensitivity study. The possible variability of key parameters in emergency dose calculations is considered, and ranges are developed for each. It starts by reviewing exposure pathways and the basic dose calculations in an emergency response assessment. This thesis describes work to investigate this imprecision and to find better ways of including it in assessments and representing it in results. These predictions will be imprecise due to lack of knowledge about the nature of the release and the weather, and also due to measurement inaccuracy. After an accidental release of radioactivity to atmosphere, modelling assessments are needed to predict what the contamination levels are likely to be and what measures need to be taken to protect human health.