STATUS OF THE HeLiCal CONTRIBUTION TO THE POLARISED POSITRON SOURCE FOR THE INTERNATIONAL LINEAR COLLIDER

The baseline positron source for the International Linear Collider is a helical undulator based design which can generate unprecedented quantities of polarised positrons (1). A major thrust of the global design in this area is led by the UK based HeLiCal collaboration (2). The collaboration takes responsibility for the design and prototyping of the helical undulator itself, which is a highly demanding short period device with very small aperture, and also leads the start to end simulations of the polarised particles to ensure that the high polarisation levels generated are maintained from the source, right through the beam transport systems and up to the interaction point itself. This paper will provide an update on the work of the collaboration focussing on these two topic areas and will also discuss future plans.