Self amplified stimulated emission free electron laser production from electron energy above 1.5 GeV is studied to obtain 1-100 nm laser wavelength. Design simulations of linear accelerating system with gun and enjector system has been done in more detail by considering space charge effect for electron beam. Electromagnetic field for superconducting cavities, solenoid fields, cavity defects such as Higher Order Modes, Multipacting, Lorentz Force Detuning, and beam behaviour along the beamline are very important details for this study. Optimised cavity cell design layout are provided in order to obtain quality factor 10(9) for designed cavities throughout the main linear acceleration. To determine coupling factor, and zero modes and also other modes with relative errors are searched.