The Principle To Measure The Concentration And The Content With Compton Scattering

Material is the milestone and the matter basis for the development of human society. So the development of new material is one of the most important and potential fields. New material's development depends on that of material science, which focuses on the study of the relations between component, texture, structure, machining and the capability of the material. And the measurement of component, texture, structure, machining and capability relies on the constant development of the analysis and testing technique of material. This thesis is to exploit a new analysis and testing techniques to measure the concentration and the content of the scatterer through the Compton scattering phenomenon. And its success will be of profound theoretical and practical significance.Through the study of the Compton scattering of acid, alkali, salt solutions, powder mixture and alloy, based on systematically of the Compton scattering, the analysis the author has deduced the expression theoretically between the Compton scattering photon counts and the concentration of solutions, or between the Compton scattering photon counts and the content of powder mixture and alloy. The results show that the relationship is linear between the concentration of solutions (or the content of powder mixture and alloy) and the Compton scattering photon counts. And this has laid a theoretical foundation for the measurement of the concentrations and contents through Compton scattering.Through the Compton scattering experiments of acid, alkali and salt solutions, it is proved that the relationship is linear between the concentration of solutions and the Compton scattering photon counts on the condition that the radiation source is Cs¹³⁷(the ray energy is 661.5kev). And the line slope is different for different solutions. But for the different alkali solutions and different salt solutions of the alkali metal, there is something similar: with the increasing of the metal's atomic number, the line slope is decreasing. It is proved that the Compton scattering method can be used to measure the concentration by theoretical deduction and by the results of the Compton scattering experiments.The Compton scattering experiments of Cu-Ni powder mixtures and Fe-C powder mixtures when adopting theγray source Cs¹³⁷ as the radiation source show that the Compton scattering photon counts are increasing linearly with the increasing of the Ni (or C) content in the powder mixture scatterer. On the one hand this proves the formula by deduction is theoretically correct, and on the other hand, it also shows that the content of certain component in the powder mixture can be measured with the Compton scattering method. The comparison between Cu-Ni powder mixture (the difference between the two atomic numbers is 1) with Fe-C powder mixture (the difference between the two atomic numbers is 20) displays that the slope of the latter is sharper than that of the former. This means, the larger is the difference between the atomic number of the two components of the mixture,the higher is the sensitivity of the method.The Compton scattering experiments with Cs¹³⁷ as radiation source of Cu-Ni infinite solid solutions show that the Compton scattering photon counts are increasing linearly slowly with the increasing of Ni content in the infinite solid solutions. Nevertheless, the slope of the line is very small. Comparing the result of the Compton scattering of Cu-Ni infinite solid solutions with those of the Cu-Ni powder mixture, the author finds that the sensitivity of the method is lower. This is related with the change of the electronic structure of the scatterer. The Compton scattering experiments of Fe-Cu finite solid solutions, show that there is no obvious change of the Compton scattering photon counts with the Cu content increasing in the Fe-Cu alloy. The result shows that the Compton scattering photon counts are not only related to the electron density of the scattered, but also are related to the freedom degree of the electrons. With the increasing of Cu content, there is a balance between the electron density and the freedom degree of the electrons, so that there is no obvious change of the scattered photon counts. From this we can see that this method is not fit to measure the Cu content in the scatterer of Fe-Cu alloy.Through the density functional theory method of the quantum chemistry, the electron structure of ion hydrates of some solutions, including H₂SO₄, HCl, LiCl, NaCl, KCl, NaOH, KOH, MgCl₂and BaCl₂ has been computed and analysized. The analysis of the electronic density distribution of the cation H+, Li+, Na+ and K+ shows that the overlapped electronic density is decreasing in the order of the cation H+, Li+, Na+ and K+. It shows that the bound energy of electron becomes larger in the order of the cation H+, Li+, Na+ and K+. For the same reason, the bound energy of electron becomes larger in the order of the cation Mg²⁺ and Ba²⁺ in the Mg²⁺ and Ba²⁺ hydrates system. And the bound energy of electron becomes larger in the order of the cation Cl^- and SO₄^2-in the Cl^- and SO₄^2- hydrates system. The law that the bound energy of electron becomes larger for the ion hydrate system agrees with that of the linear slope which demenstrates the relationship between the concentration and the scattered photon counts in the Compton scattering. It can reasonably explain the law of the linear slope which shows the relationship between the concentration and the scattered photon counts in the Compton scattering with the result from the quantum chemistry.Through the employment of the plane-wave pseudopotential method based on the density functional theory (DFT) in Quantum Chemistry, the author calculates the partial density of states (PDOS) and atomic populations of Cu-Ni alloy and Fe-Cu alloy. The analysis shows that the more is Ni content in the Cu-Ni alloy, the more of the electrons move away the Fermi surface. This indicates that the electrons are becoming freer. And it can explain the experimental phenomena which express the relationship between the Compton scattering photon counts and the Ni content in the alloy. It also shows that the more is Cu content in the Fe-Cu alloy, the more of the electrons move towards the lower energy level from the Fermi surface. This indicates that the electrons are bounded more strongly. And under the condition that the electron density is little changed, the strength of the electron bounded will influence the Compton scattering photon counts in the Compton scattering experiments.After the comparation of the rule of Compton scattering of the acid, alkali and salt solutions, powder mixtures and alloy, the Compton scattering method is promoted, which can measure the concentration of the solution and the content of powder mixture without touching the scatterer. And then automatic measurement and online measurement can be realized easily of the concentration of the solution and the content of powder mixture. But the method to measure the content of the alloy needs to be studied further.