Study Of High Spin States In ¹²³I

The atomic nucleus is a multibody system that can be excited in many kinds of quantum mechanics ways.The competition and interaction between the single particle movement and collective movement is the important factor which determines the nuclear structure.The nuclei near closure shell are spheric,and predominantly have single particle structures.The nuclei which are far from the closure will have deformation and the level scheme will represent a strong collective character.The generalized A～130 transitional region refers to the nuclei from the closed shell spherical nuclei(Z=50)to the rare-earth nuclei(Z≥57).There are two characteristics of the nucleus in this area:One is valence protons and neutrons are both in h_11/2shell,and the fermi surfaces of protons and neutrons are in the lower and higher part of the h_11/2shell respectively.So they have different shape driving effect;The other is that the nuclear deformation isγsoft,and triaxial deformation potential energy surface is very smooth and easy to have a triaxial deformation.It is precise because this is the nucleus of the above characteristics of their high spin states,showing a very rich structure of atomic muclei has been a high-spin states of the regional hot spots.This paper is on the A～130 at the transitional area of ¹²³I high spin states.The content of this paper is divided into three parts:Introduction,The in-beamγspectroscopy experiments,Offiine data analysis and discussion. Introduction contains the following aspects:Firstly,briefly review of the course of development of nuclear physics,introduce the several methods of atomic muclei population of high spin states,and compare their advantages and disadvantages respectively;Secondly,detail the nucleus of several common models;Finally,I introduce the ¹²³I nuclear research background,and further explained the original intention of this work and research purposes.The paper mainly discusses the second part:the beamγspectroscopy experiment.The high spin states of ¹²³I is populated through the fusion reaction evaporation ¹¹⁶Cd(¹⁴N,5n2p).The experiment is completed by Dr.Komatsubara, the University of Tsukuba,Japan,in Denmark,Bohr.The main purpose of the experiment is ¹²⁶Cs high spin states and ¹²³I belongs to a reaction road.¹¹⁶Cd target thickness is about the quality of 820,with a target of steam afer the lining. Selected experimental beam energy was 65MeV,and experimental detection arrays comprised of 19 Taiwan ACS HPGe detector and a small plane detector. After data inversion,the double line with the totel mumber of incidents reached a 8×10⁸.Although the practical reason(the author did not participate in the experimental measurements)doesn't let me describe experimental equipments and processes in detail,the author has participated twice in the esperimental work on the high spin states at the Beijing tandem accelerator.Therefore,take the institute of atomic energy HI-13 tandem accelerator atγterminal as an example,I introduce the experimental procedures and methods of the in-beamγspectrum and carried out a detailed explanation about several major laboratory equipments.The last part of the article is offiine data analysis and experimental results discussion.Firstly,we recorded the data acquisition system of data inversion and got the E_γ-E_γmatrix which was used for the analysis of the symmetry. Then we projected to the symmetric matrix of the x-axis or the y-axis and produce the total spectrum;Finally,we identified the accordance correlation between theγ-rays through gating.According to the relationship and various factors,such as cascade relationships and intensity balance,we reestablished of the ¹²³I-level gang map and firstly found more than 30 newγ-ray in this work. By extracting alignment angular momentum and analyzing the correlation between alignment increment and configuration,a new band which fed into the previously knownÏ€g_7/2rotational band was tentatively assigned toÏ€g_7/2[404]7/2⁺(?)(vh_11/2)² coupledγvibration band.Band on the previous work, we extended the level structure of a strong coupled side band.Through assigning the multipolarity of the transitions feeding the knownÏ€g_9/2rotational band and the foundation and affirment of the inportant linking transition 962keV,ultimately we identified the configuration of this band,namelyÏ€g_9/2 coupled toγvibration band.The work has solved the many-year question on the assignment of this band.In conclusion,the work improved the original ¹²³I-level scheme,further enriched the A～130 isotope nucleus structure.The new foundγ-rays and the band structure provided the new evidence to systematic studies of the nucleus and the understanding of the uclear nature,as well as provided a new foundation on more theoretical and comprehensive analysis.Nevertheless, because a number of issues are still left,the relative work still needs to be done.