Status of the HeLiCal contribution to the polarised positron source for the International Linear Collider

The positron source for the International Linear Collider (ILC) is a helical undulator-based design, which can generate unprecedented quantities of polarised positrons. The HeLiCal collaboration [1] takes responsibility for the design and prototyping of the superconducting helical undulator, which is a highly demanding short period device with very small aperture, and also leads the start to end simulations of the polarised electrons and positrons to ensure that the high polarisation levels generated survive from the source up to the collision point. This paper will provide an update on the work of the collaboration, focusing on these two topic areas, and will also discuss future plans.