양성자 빔 이용 미량원소의 정밀분석 응용 연구

Abstract

The purpose of the research is that design an appropriate proton extraction beam line to enhance KIRAMS-13 utilization. Using the beam line, a PIXE-PIGE analysis system would be developed to ensure the ion beam analysis technology. Also, using government supported research facilities, the utilization plan of public experiment device and human resource plan should be established. In general, a proton beam is used for PIXE and PIGE analysis to measure an abundance of atoms. The proton beam, which has an appropriate energy, could be generated based on large accelerator facilities. Currently, the electrostatic accelerators, such as a tandem and Van De Graaff generator, are widely used on ion beam research fields. The PIXE-PIGE analysis are using the x-ray or gamma-ray which are generated based on the interactions between the proton beam and the target material. It could be determined the content of atoms or abundance based on non-destructive method. Therefore, the system is required the high technology of design and analysis. Also, it is difficult to built a PIXE-PIGE analysis system in ordinary laboratory, because the cost of the proton beam generator is expensive. In this paper, the cyclotron, which is developed by Korea Institute of Radiological And Medical Science(KIRAMS) and called KIRAMS-13, would be applied the ion beam analysis. The KIRAMS-13 could generate 13 MeV of proton beam, which can be used on the ion beam analysis also other proton beam application fields. So, the proton beam utilization facilities using the KIRAMS-13 should be established.

In general, the cyclotron generated proton beams are diverged. In case of medical cyclotron, the beam divergence helps to produce radioisotopes. At this study, to deliver the proton beam until the PIXE-PIGE analysis chamber, which is located at the end of the beam line from the cyclotron, an effective beam transport line was designed. Also, the various components of the beam line were designed such as magnets, power supplies, beam current control chambers, faraday-cups, PIXE-PIGE analysis chambers, and detectors. The beam line components were manufactured and installed based on the design of PIXE-PIGE analysis system. The total 10 magnets and power supplies, such as bending, doublet quadrupole, triplet quadrupole and steering, were manufactured and installed.

A beam current control chamber was manufactured to stop and manipulate beam current. The chamber was improved to install a vacuum device. In addition, the previous cyclotron control program problems were fixed. For the appropriate beam line control, a LabVIEW based control program was developed for the magnet, power supply, and the target control. The beam line optimization studies were performed based on the sub-projects. At the first sub-project, a control program was developed for magnets, vacuum device, and the PIXE-PIGE target. Using the developed program, the sectional beam extraction experiments were performed. At the second sub-project, the optimal beam extraction parameters were obtained by measuring the extracted beam emittance.

The beam extraction experiments were performed based on the optimization study of the beam line. During the beam extraction, the beam shape and current were measured by each section. The experimental results show that about 40% of extracted 13 MeV proton beam from the cyclotron was delivered until PIXE-PIGE analysis chamber. In case of 3 ~ 5 MeV proton, which would be used in PIXE-PIGE analysis, about 0.02% of proton was delivered. Most of the extracted beam were lost by the energy degrader and bending magnet. Based on the beam extraction experiments, the cyclotron operation parameter and beam line parameter were obtained.

At this study, various ion beam experiments were performed. The first experiment was the proton activation analysis(PAA), which is using 13 MeV proton without energy degradation. The second experiment was PIXE analysis and PIGE analysis, which is using degraded proton beam, which has 3.5 MeV energy range. At the PAA experiment, the abundance of stable strontium (87Sr/86Sr) was measured. The PAA results shows the accuracy as 96.2±3.8% compared with TIMS analysis result. This results shows that PAA could be applied on the abundance measurement of rock.

For the PIXE and PIGE analysis, various materials were exposed by 3.5 MeV proton beam. The measurements of characteristic X-ray and gamma-ray after the proton irradiation are interesting experiments. At this experiment, the reaction rates of proton exposure were measured. The result shows that PIXE and PIGE analysis should be linked each other.

Through this study, the cyclotron based beam line components design technology was obtained. The major components for this kind of beam transport line were magnets, power supply, vacuum, PIXE-PIGE analysis chamber, faraday cup, and beam monitors. Also, the beam conditions from the cyclotron were ensured from the 13 MeV and 3.5 MeV proton transport beam line study. Through this study, the beam line optics design technology was obtained. The developed control program, which was based on the previous cyclotron control program concept, can control the beam line magnet and PIXE-PIGE target. The patent using the developed program is pending. Also, the established PIXE-PIGE analysis system can be contributed to production of outstanding research results.

The established PIXE-PIGE analysis system is a typical device on the determining the element make-up of a sample. The system is definitively necessary on the archeology. Also, the medical cyclotron generates high enough proton beam, which can be successfully applied on PIXE-PIGE analysis and basic science fields using nuclear reactions. Therefore, the PIXE-PIGE analysis system can be utilized various fields such as archeology. Also, many educational programs using proton beam can be developed and used to train the next generation on physics and nuclear engineering fields.