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3.5 Comparison with the characteristic F(x) of a basic model, and the characteristic Fp(x) of a practical use model In order to investigate the difference of the characteristic Fp(x) and the characteristic F(x), the ratio Fp(x)/F(x) was calculated. The details were shown in Fig. 6, in many calculating points, the ratios were less than 1.0±0.02, and the maximum ratio was 1.0+0.054. sensitivity ratio sensitivity ratio sensitivity ratio 1.2 1.1 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 1.2 1.1 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 1.2 1.1 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 E type model Fp(x)/F(x) 0.01 0.1 1 10 photon energy [MeV] Hp(10,0°) type model Fp(x)/F(x) 0.01 0.1 1 10 photon energy [MeV] Hp(007,0°) type model Fp(x)/F(x) 0.01 0.1 1 10 photon energy [MeV] sensitivity ratio sensitivity ratio sensitivity ratio 1.2 1.1 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 1.2 1.1 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 1.2 1.1 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 H*(10) type model Fp(x)/F(x) 0.01 0.1 1 10 photon energy [MeV] H'(10,0°) type model Fp(x)/F(x) 0.01 0.1 1 10 photon energy [MeV] H'(0.07,0°) type model Fp(x)/F(x) 0.01 0.1 1 10 photon energy [MeV] Fig.6. Comparison of the synthetic characteristic F(x) created from the combination of the characteristics from the basic model, and the characteristic Fp(x) of the practical use model based on the ki values. 4. Discussion The latest photon transportation Monte Carlo calculation code is very highly precise, and can per<strong>for</strong>m a simulation reliable if a user code is constructed strictly. Moreover, since it is a simulation, irradiation conditions with difficult realization can be set up easily, and detailed in<strong>for</strong>mation can be acquired compared with an irradiation experiment. We applied the advantage of such a calculation code to the sensitivity compensation filter design <strong>for</strong> fluorescence glass dosimeters, and tried the design of the 6
filter which can measure an effective dose or a dose equivalent. It was started from acquisition of basic data and the procedure of composition of the characteristic needed <strong>for</strong> the dose measurement from the data subsequently acquired, planning of the practical use model which can maintain the compounded characteristic, and evaluation of the model per<strong>for</strong>med the design. It was thought that this procedure was useful in order to be able to design a new filter certainly and to raise the efficiency of a filter design. The method of using the calculation code <strong>for</strong> the design does not need large-scale equipment, but can also save the time and ef<strong>for</strong>t of an experiment. So, the effect which reduces the expense of development sharply is expected. In the simulation of the basic model, the details of the energy characteristic could be known and the filter was designed based on this basic data. In the practical use model, the characteristic as expected was obtained and it was suggested that this method can serve as a leading means <strong>for</strong> the design of a filter. For this designed filter model, the characteristic was examined in the photon energy range of 0.01-10.0MeV. However, the energy range which can use the designed filter was narrowed by the photon absorption characteristic which a tin filter has at 0.03-1.0MeV, and the utility value became low.In the domain in which photon energy exceeds 1.0MeV(s), it was considered as a cause in which shortage of filter thickness weakens sensitivity, and in the domain below 0.029 MeV with photon energy lower than K absorption edge of tin, since the K absorption did not take place, the rise of partial sensitivity was observed. It was the result of reflecting the K absorption edge in this characteristic that the characteristic of a glass element became discontinuous at the photon energy of 0.029MeV. These problems may be able to be conquered by examining the quality of the material of a filter, and are due to be examined further from now on. Since the trial production of the practical use filter is not per<strong>for</strong>med now, the characteristic shown by actual measurement with the designed filter is not clear. However, the error of an old experience to an actual measurement and a simulation is very small, and it is sure that this method can use <strong>for</strong> a design in a comparatively simple model like the design of a filter. Even if slight gap arose between the measurement and the simulation, from the energy range which the gap produced, if which of the coefficients of the <strong>for</strong>mula (1) is adjusted, it can presume easily whether the characteristic improves. The technique which we adopted by this research does not need large-scale equipment in the development stage of a filter, but if there are a personal computer and a reliable Monte Carlo simulation code, it can carry it out. It will greatly be used <strong>for</strong> development of various measuring instruments which need the new characteristic in the radiation field by this technique in the near future. 5.Conclusion Development of the sensitivity compensation filter <strong>for</strong> glass dosimeters was tried using the reliable Monte Carlo calculation code. Collecting required in<strong>for</strong>mation through the gradual process from acquisition of basic data, the technique of us which compounds the target characteristic based on the in<strong>for</strong>mation carried out the purpose achievement, without inducing a big error in the specific photon energy range. Development of the filter corresponding to various doses is due to be tried from now on in a different photon energy range using the same technique. 6.References 1. Perry, J.A., Radiophotoluminescence in health physics, Series in Medical Physics and Biomedical engineering, (1987). 2. Juto, N., The Large Scale Personal Monitoring Service Using The Latest Personal Monitor GLASS BADGE, Proceedings of AOCRP-1, Korea (2002) 3. Piesch, E., Burgkhardt, B., and Vilgis, M., Progress in Phosphate Glass Dosimetry: Experiences and Routine Monitoring with a Modern Dosimetry System, Radiation Protection Dosimetry, 47, 409-414, (1993) 4. Namito,Y., Hirayama, H., and Ban, S., Improvements of Low-energy Photon Transport in EGS4sytem, Proceedings of The first international Workshop on EGS4, KEK proceeding 97-16, 2-50 , (1997) 5. Nelson, W.R., Hirayama, H., and Rogers D.W.O., The EGS4 Code System, SLAC Report 265(1985) 7
Page 1 and 2: The Design by the Monte Carlo Metho
Page 3 and 4: was standardized so that it was set
Page 5: Table 1. Coefficients ki of the cha

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