  The ATLAS Forward Physics (AFP) project plans to install 3D silicon pixel
detectors about 210 m away from the interaction point and very close to the
beamline (2-3 mm). This implies the need of slim edges of about 100-200 $\mu$m
width for the sensor side facing the beam to minimise the dead area. Another
challenge is an expected non-uniform irradiation of the pixel sensors. It is
studied if these requirements can be met using slightly-modified FE-I4 3D pixel
sensors from the ATLAS Insertable B-Layer production. AFP-compatible slim edges
are obtained with a simple diamond-saw cut. Electrical characterisations and
beam tests are carried out and no detrimental impact on the leakage current and
hit efficiency is observed. For devices without a 3D guard ring a remaining
insensitive edge of less than 15 $\mu$m width is found. Moreover, 3D detectors
are non-uniformly irradiated up to fluences of several 10$^{15}$
n$_{eq}$/cm$^2$ with either a focussed 23 GeV proton beam or a 23 MeV proton
beam through holes in Al masks. The efficiency in the irradiated region is
found to be similar to the one in the non-irradiated region and exceeds 97% in
case of favourable chip-parameter settings. Only in a narrow transition area at
the edge of the hole in the Al mask, a significantly lower efficiency is seen.
A follow-up study of this effect using arrays of small pad diodes for
position-resolved dosimetry via the leakage current is carried out.
