The absorption intensity and the peak wavelength of the 570-nm band, which is observed at LNT after fast neutron irradiation of MgO, vary appreciably depending on the concentrations of the impurities such as Fe or Mn, and the behavior of this band during isochronal annealing is characteristic. From these facts it may be proposed that the absorption at about 570 nm may be attributed to more than the two kinds of color centers.

  The growth of the 352- and 975-nm bands, which accompany the zero-phonon lines at 361.8 and 1044nm, respectively, caused by fast neutron irradiation is controled by the addition of impurities.

  The 351-nm band and the 338-nm line are observed at LNT in the CL cathodoluminescence spectra of the samples irradiated by protons and fast neutrons at the temperatures below LNT, but they are not observed of the sample irradiated at the temperatures higher than the room temperature. The half-width of the 338-nm line at LNT is 4.4A.

  Brief reports have been given about the current results of the stopping power measurements done at GSI (Gesellschaft für Schwerionenforschung mbH) in West Germany. Major concerns are the obtained dependences of stopping powers on atomic numbers of both ions and target atoms as well as energy for ions from Ar to U with energies of 0.2-5 MeV/amu. Discussions have been also made on energy straggling in conjunction with charge fluctuations of ions.

  The relative scintillation efficiency due to α particles, fission fragments and electrons in liquid argon and xenon have been measured. A reduction of scintillation efficiency due to fission fragments is observed. The ratios of the scintillation efficiencies due to light and heavy fragments to that due to α particles are 0.244±0.005 and 0.232±0.005, respectively, for liquid argon, and those for liquid xenon are 0.30±0.01 and 0.31±0.01, respectively. The scintillation efficiencies due to electrons are 1.1±0.2 and 0.81^+0.07_-0.13 of those due to α particles for liquid argon and xenon, respectively.