  An instrument has been developed for precision controlled exposures of
electronic devices and material samples in particle beams. The instrument
provides simultaneously a real time record of the profile of the beam and the
fluence received. The system is capable of treating devices with dimensional
scales ranging from millimeters to extended objects of cross sections measured
in tens of square centimeters. The instrument has been demonstrated to operate
effectively in integrated fluences ranging up to a few times $10^{16}$
1-MeV-neutron-equivalent/cm$^{2}$ (n$_{\textrm{eq}}$). The positioner portion
of the system comprises a set of remotely controllable sample holders
incorporating cooling and interfaces for sample power and readout, all
constructed from low activation technologies. The monitoring component of the
system samples the current or voltage of radiation tolerant silicon diodes
placed directly in the path of the beam.
