Differing damage effects were observed in these materials when they were irradiated with light or heavy ion beams. Color centers which were stable at up to 240K were observed in both compounds when they were irradiated with beams of 22MeV 2H+ to fluences of less than 1016/cm2. At fluences of between 1016 and 2 x 1016/cm2, no further damage was observed in KH2PO4, but the NH4H2PO4 crystals exhibited a light color which was stable up to the melting point. After bombardment with 88MeV 16O6+ ions, where dense valence-electronic and nuclear interactions became important, the clustering of point defects and the creation of extended defects occurred.

M.A.R.De Benyacar, A.Carabelli, H.Lanza: Radiation Effects and Defects in Solids, 1994, 128[4], 357-62