Physico-chemical Studyof Some Prepared Dyed Films and Possible Application as Radiation Dosimetry

Abstract

The main objective of this work is to study the possibility of prepare and use of some rods and dyed plastic films as gamma radiation dosimeter. The obtained results in this work can be summarized in the following: Section (1): In this part EPR (electron paramagnetic resonance)technique is used to evaluate the dosimetric properties of mono sodium glutamate powder and rods. Mono sodium glutamate (powder and rods) proved their dosimetricbehaviour through stable formed free radicals obtained after irradiation. Powder is useful dosimeter to dose range up to 90 kGywhile mono sodium glutamate rods are useful to dose range (5-120 kGy).The EPR signal intensity for powder and rods increase in with the increase of absorbed dose.The EPR signal intensity increases with the increase of sodium glutamate in the rods.''G-value''The number of free radical formedper 100 evwas 0.201.The preparedrods havean excellent stability before and after irradiation during the storage time, also it has negligible effect of relative humidity in the range of (0-60%RH)Mono sodium glutamate rods dosimeter can be used as a dosimeter in food and medical irradiation application processing. Section (2): Deals withthe investigation of some pH indicator dyedPVA film and its possible use either as a dosimeter or label for radiation processing. This section is divided into two parts. Part (1): Prepared film from poly (vinyl alcohol) dyed with a mixture of two dyes, chlorophenol red (CPR) and quinalidine red (QR) with different concentrations of chloral hydrate. The color of this film changes form dark red to yellow. The first step of this reaction is the bleaching of quinaldinered , then the gradual transformation of CPR to its acidic form (yellow color) begins at 3 kGy. Complete irradiation of this film leads to complete bleaching of QR and complete transformation of CPR to acid form at 18 kGy.The useful dose range is up to 18 kGy. The response of this film is affected by change in chloral hydrate concentration and also the ratio of the two combined dyes.Complete bleaching of QR occurs at 18 kGy instead of 90kGy when QR/PVA irradiated separately and the transformation to acidic form of CPR was retarded to be 18 kGy instead of 3.5 kGy.This reflects that sensitivity of QR towards gamma radiation is higher than CPR. The films show negligible humidity in the range (0-75%) relative humidity, alsothe film have satisfactory stability before and after irradiation. QR/CPR/PAV film can be used as routine dosimeter as well as used as lable.