とりあえず、書きました。文法的にもいろいろと問題ありなんで、まだまだ修正の必要あり Nucleus consits of two component, proton and neutron. Proton has a electric charge, but neutron is neutral particle. But their mass is very similar. In some senses they are the same particle, but different states. It is called isospin. Proton's isospin is + 1/2, and neutron's isospin is - 1/2. Of course, in electromagnetic interaction their property is very different. But, nuclear force, which makes possible to combine nucleons, proton and neutron acts as if they are the same particle. So if electromagnetic interaction is neglectable, the neuclei with the same number of nuclons has very similar structure. Our reserch's purpose is to examine isospin symmetry. To see the neuclei's structure, we observe the excited states of isomultiplet. If they have similar structure, their enegy levels must be very similar. The principle of this experiment is very simple, to collide a certain energy of particle and the nuclei, and observe scattering particle's energy. We use tandem Van de Graaf accelerator in this experiment. In this experiment, we observe three isodoublet A = 11,13 and 27, one isotriplet A = 14. But all the multiplet nuclei are not stable, we make unstable nuclei by stripping and pick-up reactions. For example, we want to observe the excited state of 14C, but it is unstable. It is impossible to use 14C as a target. But, 13C target is stable and we can use. We use deutron as a beam, and observe proton, it is called stripping reaction. A neutron is stripping from the projectile and captured by 13C nucleus. From measurement of the angle dependence of the differential cross section, we can determine which single-particle state neutron captured. Using either stripping and pick-up reaction, we must identify scattering particle. We use E - dE method. This method requiares two SSD, very thin one and thick one. The former is delta E counter, and here particle only lost little energy. The latter is E counter, and here particle lost all energy after pasing delta E counter. The energy lost in delta E counter depends on the total energy and particle. It is possible to calculate from the Bethe-Bloch formula. Different particle but the same energy lost different energy in delta E counter, so we can identify the particle and reaction.
