Phoswich scintillators have been tested for use in the focal plane detector of the Magnetic Proton Recoil (MPR) spectrometer for measurement of neutrons over the energy range 1.5 to 18MeV emitted from fusion plasmas created in the JET tokamak. The tests were performed on prototypes to detect protons over an area of 90 x 10 mm2 with two layers of 0.3 and 2.5mm thickness of fast and slow decay times with PM tubes attached to one or both ends; comparison were made with MPR monolithic scintillators. The tests were performed with a and b radiation sources besides with accelerator beam protons to measure the waveforms of the pulses generated in either or both the scintillator layers depending on the range of the radiation. The purpose of the test was to determine the efficiency of using pulse shape as a mean to identify protons of different energies and the accuracy by which this could be done in order to achieve effective separation from background radiation. The pulse shape was represented as the integrated early and late periods of the waveforms (A1 and A2) where the protons appear well localized compared to the spread-out background events. The results were used to define the design for construction of the phoswich hodoscope as the main part of the upgrade of the spectrometer (MPRu) and to characterize its performance under the measurement conditions at JET. The performance of the phoswich scintillators as installed in the MPRu is also presented based on initial measurements at JET.