A Brief Review of the Gamma Ray Free Electron Laser Undulator Design Parameters for International Linear Collider Operation

In this paper, we make a review of the International Linear Collider design with regard to its positron source. The properties of the intense gamma ray undulator radiation of the dedicated free electron laser is reviewed. We review the discussions about the proposed undulator parameters to obtain an efficient operation of the positron source. The proposals and experimental results about the optimization of the positron beam yield, undulator properties, the injected electron beam energy, polarisation qualities of the produced gamma rays and the positron beam, are discussed. Alternative ideas and suggestions about the use of excess gamma rays in other nuclear energy experiments or the use of positrons in the undulator instead of electrons are also mentioned.