چكيده به لاتين
In each light source or synchrotron radiation laboratory, several beamlines provide services to synchrotron radiation users simultaneously. The EXAFS beamline is one of the Iranian Light Source Facility (ILSF) beamlines. Each beamline consists of three main parts, which are the radiation source, the frontend section, and the optical section of the beamline. The radiation source is located in the storage ring and the passage of the electron beam through it produces synchrotron radiation. The presence of a radiation source changes the characteristics of the electron beam in the storage ring. Therefore, two main objectives are pursued in this thesis, first the design of different parts of the EXAFS beamline and then the study of the effects of the beamline radiation source on the electron beam dynamics in the storage ring.
The design of the beamline starts from the design of its radiation source. The energy range and flux of the produced synchrotron radiation are determined by the characteristics of the radiation source and the characteristics of the electron beam in the storage ring. Due to the wide energy range of 3 to 35 keV required in the EXAFS beamline, a flat horizontal wiggler is used as its radiation source.
The synchrotron radiation generated by the radiation source exits the accelerator tunnel and directed to the optical section of the beamline through the frontend section. Radiation safety and vacuum protection equipment are located in this section. Also, by using several fixed masks in the frontend section, the dimensions of the photon beam are prepared to enter the optical section.
The optical part of the beamline consists of three main elements, which are the vertical collimating mirror, the dual crystal monochromator and the focusing mirror, respectively. These three optical elements determine the dimensions and the energy resolution of the photon beam at the location of the test specimen.
After extensive studies in this thesis to find the most optimal design by considering the constraints related to cost, manufacturing, and supply of the required materials with the priority of manufacturing equipment in the country, the 3D model of two horizontal wiggler for the radiation source of the EXAFS beamline have been designed. The difference between these two wigglers is in the vacuum technology they require. The designed wigglers are In-vacuum and out of vacuum. In designing the optical part, to achieve the highest possible radiation quality in the beamline, two different coatings of rhodium and platinum have been used for both collimating and focusing mirrors. To achieve energy separation of the order of 1 keV in the whole energy range, two silicon crystals with different Miller coefficients have been used in the monochromator. the results of ray tracing from radiation source to test sample shows that the designed beamline can fully meet all the predetermined needs of users of this beamline.
In this thesis, to study the electron beam stability in storage ring, an algorithm has been developed to investigate the effect of errors on the performance of the electron beam, in which the two-step correction method is used for the first time. This algorithm helps to greatly compensate the destructive effects of errors on storage ring performance. In the next part of this research, the effects of radiation source on beam dynamics are studied in detail, as a result of which, for the first time, an algorithm for calculating the electron beam characteristics in the presence of radiation source is developed by Ohmi envelope method. This method can accurately predict some effects that were not detectable by previously conventional methods. All the algorithms developed in this thesis are written in general and can be used for similar research.
