الفهرس 
AcknowledgementOnly 14 pages are availabe for public view
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Abstract
This is an. analytical, and. 1 xper.i6ent,al study of the
effects of the environ changes on thickness gauging
of paper using. The study general discussions on the parameters affecting the radioisotopic gauges. In the analysis a formula has been reached relat¬ing the detector response to the ratio of signal change to noise ratio, minimum detectable change, and the detector sensitivity. Thp, 4najypjpjplso-includeh a, study of the detailed effects of the ambient conditions on the detector sensitivity.
Figures showing such effects are presented. A”formula for the percentage error as, a function of the density thick¬ness, relative humidity, air temperature and total pressure of the air-water vapour mixture is also presented.
To check the validity of the models presented in the analysis, an experimental investigation has been, conducted.
A specially designed apparatus was manufactured for that purpose providing possibilities of changing both tem¬perature and relative humidity of the air surrounding the experimental paper samples. Air temperature was varied from 200 to 7000 and relative humidity from 10% to 100%.
The experimental result showed that the errors result¬ing from changing of ambient condition fitted .qVit’a eil the analytical model. It is AlsUproved that :such errors are appreciable and reaches as. higi as ctemperature 60°C and relative humidity 85%.