| ?and ? planar standard sources are widely used in the radionuclide activity analysis,and they also play important roles in transmitting magnitudes such as particle emission rate and radioactive nuclide activity per unit area.Thus improving the quality of the planar source is of great significance.This paper has carried out the study of the electrodeposition method of ? planar source and the oxidation fill method of ? planar source.The test and evaluation for the technical indicators of the two sources are also included in this paper.In order to evaluate the prepared planar sources objectively and accurately,phosphor screen imaging method has been studied.After testing the metrological performance of the phosphor screen imaging instrument,we found that the phosphor screen imaging instrument has a favorable repeatability,consistency of position,and the results of its data also show a linear charge with time and radioactivity.Based on these performance as well as strictly respecting to the uniformity evaluation rules of ISO8769,the uniformity measurement to a large area source of 150mm×100mm is executed,the quantitative and intuitive expression method to the uniformity of a plane source is established,so as to develop a reference method of improving the preparation process to plane source in accordance with the ISO8769 international standard.Phosphor screen imaging method can be used for detecting the distribution of the radionuclides intuitively.By viewing the image phosphor screen imaging figures,we can distinguish the distribution of the radioactive material,providing reference for improving the preparation procedure of the planar source.Electrodeposition method is one of the important methods to prepare ? planar source.In order to improve the technological level and the quality of the planar source,we studied the influence on the various conditions to the prepared source.In this paper,we choose the Isopropyl alcohol electroplating uranium planar source as a studying object.The experimental results showed that it is quiet important to keep the stainless steel sheet clean.Only after wiping out the oil contamination can we bond the electroplated layer with the stainless steel sheet closely.The best distance between the cathode and anode is 1.0cm-1.5cm and in this distance the spectral resolution is quite high.The uranium solution should be added into the equipment all at once.The more times we added the solution,the more uneven the nuclide distribution would be,and the spectral resolution would also be lower.An excessive amount of electroplated uranium will cause the spectrum resolution become lower.The large standard Sr-Y planar source in large area is an important measuring equipment in calibrating the surface contamination instrument.Its uniformity influences the accuracy of dissemination of the value of quantity.Usually the electrodeposition method is not suitable for preparing the ? source,so we choose oxidation fill method instead.In this experiment,liquid scintillation counter is used to test the emission rate of the effluent.It turned out that the chemical deposition efficiency of this method is 92.7%.By using the phosphor screen imaging method detection uniformity of planar source,we found that anodic aluminum film has a good adsorption ability,thus when filling the radioactive strontium solution in the equipment,we must mix the radioactive strontium solution with buffering agent,and in this way the spots will not appear on the phosphor screen image.8 pieces of Sr-Y source sized 100mm×150mm were made under the same condition.It turned out that the uniformity of the planar source is random and uncontrollable.Among all theSr-Y planar source,the best of standard deviation of the surface emission rates from each individual portion of the whole source reached 5%. |
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