Design and optimisation of the positron production chain for CLIC from the target to the damping ring

The CLIC Positron source has been designed to produce non-polarised positron beams using a hybrid target composed of a crystal followed by an amorphous target. After production, positrons are captured and accelerated to 200 MeV in the pre-injector linac and subsequently accelerated further up to 2.86 GeV in the injector linac. At this point they enter the pre-damping ring and afterwards the main damping ring to obtain the necessary beam quality for a linear collider. In this study, we have designed and optimised the beam transport and acceleration from the target to the pre-damping ring which has a limiting transverse and longitudinal acceptance. The goal of the study was to maximise the positron yield accepted by the pre-damping ring.