  The Imaging X-ray Polarimetry Explorer is a mission dedicated to the
measurement of X-ray polarization from tens of astrophysical sources belonging
to different classes. Expected to be launched at the end of 2021, the payload
comprises three mirrors and three focal plane imaging polarimeters, the latter
being designed and built in Italy. While calibration is always an essential
phase in the development of high-energy space missions, for IXPE it has been
particularly extensive both to calibrate the response to polarization, which is
peculiar to IXPE, and to achieve a statistical uncertainty below the expected
sensitivity. In this paper we present the calibration equipment that was
designed and built at INAF-IAPS in Rome, Italy, for the calibration of the
polarization-sensitive focal plane detectors on-board IXPE. Equipment includes
calibration sources, both polarized and unpolarized, stages to align and move
the beam, test detectors and their mechanical assembly. While all these
equipments were designed to fit the specific needs of the IXPE Instrument
calibration, their versatility could also be used in the future for other
projects.
