  Planar silicon pixel sensors with modified n$^+$-implantation shapes based on
the IBL pixel sensor were designed in Dortmund. The sensors with a pixel size
of $250\,\mu$m $\times$ $50\,\mu$m are produced in n$^+$-in-n sensor
technology.
  The charge collection efficiency should improve with electrical field
strength maxima created by the different n$^+$-implantation shapes. Therefore,
higher particle detection efficiencies at lower bias voltages could be
achieved. The modified pixel designs and the IBL standard design are placed on
one sensor to test and compare the designs. The sensor can be read out with the
FE-I4 readout chip.
  At the iWoRiD 2018, measurements of sensors irradiated with protons and
neutrons respectively at different facilities were presented and showed
incongruent results. Unintended annealing during irradiation was considered as
an explanation for the observed differences in the hit detection efficiency for
two neutron irradiated sensors. This hypothesis will be examined and confirmed
in this work, presenting first annealing studies of sensors irradiated with
neutrons in Ljubljana.
