  The design of the positron source for the International Linear Collider (ILC)
is still under consideration. The baseline design plans to use the electron
beam for the positron production before it goes to the IP. The high-energy
electrons pass a long helical undulator and generate an intense circularly
polarized photon beam which hits a thin conversion target to produce $e^+e^-$
pairs. The resulting positron beam is longitudinally polarized which provides
an important benefit for precision physics analyses. In this paper the status
of the design studies is presented with focus on ILC250. In particular, the
target design and cooling as well as issues of the optical matching device are
important for the positron yield. Some possibilities to optimize the system are
discussed.
