A COMPARATIVE CALCULATION OF DOSE RATE USING RAD PRO CALCULATOR FOR SHIELDING REQUIREMENTS OF COBALT-60 AND CESIUM-137 SOURCES AT CERT.
A COMPARATIVE CALCULATION OF DOSE RATE USING RAD PRO CALCULATOR FOR SHIELDING REQUIREMENTS OF COBALT-60 AND CESIUM-137 SOURCES AT CERT.
No Thumbnail Available
Date
2012
Authors
MUHAMMAD, Ibrahim
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
A Comparative Calculation of Dose Rate Using Rad Pro Calculator for Shielding Requirements of Cobalt-60 and Cesium-137 Sources at CERT. was carried out using seven shielding materials: Lead, Concrete, Iron, Uranium, Lead glass, Aluminum and Tungsten by the Rad Pro Calculator. The study was to understand the attenuation strength of these materials in relation to one another; and the behavior of the photon dose rate in relation to the thickness of the shield. These materials and of varying thicknesses were placed in between the radiation source and the detector and the dose rate were calculated .It has been observed that each of the results has a similar behavior, in that the photon dose rate is inversely proportional to the absorber thickness in an almost exponential form. As the absorber’s thickness increases, the photon dose rate decreases; conversely. From a given distance, the result of these seven absorbing materials (Lead, Concrete, Iron, Uranium, Lead glass, Aluminum and Tungsten) look very similar, but on a closer look, one will identify a striking and important differences amongst these seven materials especially tungsten. While only 6cm thickness of tungsten is required to reduce the photon dose rate of 5mCi of 60Co at 1metre distance from the source to detector to 0.08μSv/h, 6cm of uranium thickness reduces it to 0.11μSv/h , 10cm of Lead glass thickness is required to reduce it to 0.08μSv/h,12cm of lead reduce to 0.07μSv/h,22cm of Iron shielding reduce the dose rate to 0.07μSv/h,42cm of Aluminum shielding reduce the dose rate to 0.11μSv/h, 70cm of concrete shielding require to reduce the dose rate to 0.06μSv/h.This then goes to show that uranium is a far better absorber of 60Co gamma photon when compared to tungsten, lead glass, lead, iron, aluminum and concrete can be used to shield against gamma ray. Conversely, 3cm of uranium shielding is require to reduce the photon dose rate of 22mCi of Cs-137 at 1m from the source to detector to 0.05μSv/h, 4cm of tungsten to 0.07μSv/h, lead glass to 0.05μSv/h, lead to 6cm to 0.07μSv/h, 16cm of iron shielding to 0.07μSv/h, 32cm of aluminum shielding to 0.09μSv/h, 55cmof concrete shielding to 0.08μSv/h. In conclusion, Rad Pro Calculator simulation is a veritable tool for modeling certain real life situations, and very useful in shielding calculation. The result have also show that out of the seven materials, tungsten and uranium is a better shield because it requires just a few thicknesses of it to cut down the photon dose rate to acceptable limit, then followed by lead glass, lead, iron, aluminum and concrete being the least.
Description
A THESIS SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES,
AHMADU BELLO UNIVERISTY, ZARIA
IN PARTIAL FULFILMENT OF THE REQUIREMENT FOR THE AWARD
OF A
MASTERS DEGREE IN RADIATION BIOPHYSICS DEPARTMENT OF PHYSICS
FACULTY OF SCIENCE
AHMADU BELLO UNIVERSITY, ZARIA
NIGERIA
Keywords
COMPARATIVE CALCULATION,, DOSE RATE,, RAD PRO CALCULATOR,, SHIELDING REQUIREMENTS,, COBALT-60,, CESIUM-137 SOURCES,, CERT,