The Kent State University Neutron Polarimeter was located at meters from the target on the flight path. The design of the KSU detector (also called the ``'' polarimeter) is significantly different than that of the INPOL detector but it measures both particle energy and polarization in essentially the same way. Neutron energy is measured by time-of-flight and the polarization by measuring the azimuthal distribution of a second scattering. A schematic drawing of the KSU ``'' polarimeter is shown in figure
Figure: The KSU ``'' polarimeter: a) Isometric view, b) Side view [Wat94].
The analyzer for the ``'' polarimeter consists of 4 blocks of BC-404 plastic scintillator, each , situated with the long axis along the neutron's direction of motion. The neutrons will scatter into an azimuthally symmetric array of twelve BC-400 plastic scintillators, each . The angle between the centers of the front and back planes is which is near the maximum ``figure-of-merit'' for elastic neutron-proton scattering in the energy range of 100-200 MeV as can be seen in figure .
Figure: Calculated figure-of-merit for n-p elastic scattering at MeV. Maximum FOM is at [Wat94].
Each of the bars of scintillator has a phototube (XP-2020 for the front plane, and XP2041 or R-1250 on the back plane) at each end. Therefore position of the interaction is determined by a timing difference between each end. The intrinsic time resolution for the detector is given as 122 ps (FWHM), and the position resolution is 17 mm (FWHM). In a 1995 calibration an overall time resolution of 360 ps was observed, which, for 170 MeV neutrons, corresponds to an energy resolution of 580 keV at a flight path of 50 meters. Further details on the KSU ``'' polarimeter can be found in [Wat94] and [Pal95].