High energy radiation imaging

Radiation sensitive cast polymers from DADC are also used in resists for microelectronic circuitry. Relief images result from differential rates of solution in alkali induced by exposure to high energy radiations. 

Fig. 10.27. Illustration of the imaging of high energy radiation using (a) a thick p-i-n detector or (b) a phosphor to convert the radiation into visible light.

Although the electrons are the part of the atom that mostly determines its chemical properties, the nucleus is very important in all of our lives. The high energy radiation produced hy radioactive nuclides can he very harmful to us, hut it is also used in many types of medical tests. Called radiotracers, certain radioactive nuclides are introduced into the body to analyze biological functions and to provide images of organs such as the thyroid and the heart. 

In the late nineteenth century scientists discovered that certain elements produce high-energy radiation. For example, in 1896 the French scientist Henri Becquerel found accidentally that a piece of a mineral containing uranium could produce its image on a photographic plate in the absence of light. He attributed this phenomenon to a spontaneous emission of... 

Counting of High Energy Radiation Tracks. A computerized Image analyzer, the Cambridge Instrument model 900, was used to count the radiation tracks of the Irradiated polycarbonate samples. The measurements Include track size (diameter), track density In each field of view, roundness, sample area In each field, and total area of the sample. Samples of polycarbonates examined Included those prepared In our laboratory and neutron Irradiated samples provided by Dr. G. Tarle of University of California at Berkeley. 

We have shown that commercial CR-39 monomer samples can be purified by column chromatography. Polymerization with benzoyl peroxide as Initiator gives highly crossllnked polycarbonate samples suitable for use as high energy radiation dosimeters. A method has been developed to characterize the polymer and to count radiation tracts with a computer controlled Quantlmet Image analyzer. 

Warman, J. M. de Haas, M. R Luthjens, L. H. Horn, M. L. High-energy radiation monitoring based on radio-fluorogenic co-polymerization III Fluorescent images of the cross-section and depth-dose profile of a 3 MV electronbeam. Radial Phys. Chem. 2013,84, 129-135. 

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