Positron capture simulation for the ILC electron-driven positron source

The International Linear Collider (ILC) is a next-generation accelerator for high-energy physics to study the Higgs sector in the Standard Model in as much detail as possible and to search for new phenomena beyond the Standard Model, such as supersymmetry and dark matter. In the current design of the positron source for the ILC, positrons are generated by pair creation in a Ti (titanium) alloy target via gamma irradiation. The gamma rays are generated by undulator radiation with electrons at more than 150 GeV. This positron generation scheme is an unprecedented approach; therefore, it is desirable to have a technical backup for the ILC positron source. We study a positron source for the ILC based on the conventional electron-driven scheme. In this scheme, a positron beam is generated by an electron beam of several GeV impinging on a W-Re (tungsten rhenium) alloy target. The heavy heat load and target destruction are potential problems, but they are alleviated by stretching the effective pulse length to 60 ms instead of 1ms. In this article, a start-to-end simulation of the electron-driven ILC positron source is reported. According to the simulation, sufficient positrons can be generated while the target heat load is kept below the destruction threshold.