The Research Method Of NaI Detectors Simultaneously Measure The Angular Correlation Of The ? Transitions

All Radio nuclides can spontaneously emit ? or ? rays,some time emit ? rays while emitting ? or ? rays,and some time emit above all rays.In addition,there are other particles such as protons,neutrons and positrons are emitted.The emission probability of radioactive nuclear ? rays or other particles are often related to the angle between the direction of the nuclear spin and the direction of the emitted particles.the orientation of the nuclear' s spin is not certain,because of the disorder of the nuclear spin orientation and the angular distribution of the nuclear radiation of each atom is super imposed together,then the result is the isotropic effect.In order to observe the angular distribution of the nuclear cascade radiation,the spin of the nuclear requires a certain degree of orientation.One way of nuclear spin orientation is to settle down the spin direction of the nucleus and make it‘s polarization.But the method not only is very complex,but also cannot be used for all nuclear.Another research method is that collect the spin orientation which is directing to the nuclear of spin disordered nucleus.In this paper,the angular correlation of the ? ray of 60 Co and 22 Na radiation source decay is measured by using NaI scintillation detector that is based on the experimental platform designed by ourselves.After Changed the angle between the two detectors at an obtuse angle range,measured different angle's coincidence counting rate and calculated the corresponding angular correlation function and anisotropy degree.The trend of the experimental angular correlation curve is similar to the theoretical curve of the nuclear cascade 4(2)2(2)0,The anisotropy of the experimental data that obtained from the angular correlation measurement is Aexp=0.1666±0.0623.respectively,These experimental values are close to the theoretical anisotropy 4(2)2(2)0 of nuclear cascade Ath=0.1667.The result shows that when the 60 Ni nuclear cascade emitted two ? rays,the cascade transition occurs between the energy levels of spin that are 4,2,0,and both ? rays' the angular momentum are equal to 2.The angular correlation function and the experimentalvalue of the anisotropy are compared with the theoretical values by obtaining the angular momentum of the atomic energy level and can determine the character of cascade transition and the way of ? transition.From the experimental data and the angle correlation curve of the radiation source of 22 Na,it can be conclude that there is relationship with the angle between two detectors and counting of the moving detector,and the counting of the moving detector increase with the increasing of the angle.When the angle is 180°,the direction of the two ? rays generated by the electron annihilation,which has the same direction with the two detectors.So the two ? rays are fitted well each other,which makes the experimental data of the corner correlation function become larger.After comparing the results with the research methods of domestic and abroad,we have improved the shortcomings of the experiments and tested the feasibility of self-made testing platform and experimental methods.