Two-component effective medium theory (EMT) is applied to calculate binding, migration and dissociation energies of helium, neon and argon in bulk copper. Interstitial helium and neon prefer octahedral sites whereas argon sits about 0.5 Å off-centred in the octahedral site. Helium has the smallest migration energy, but, surprisingly, the migration energy of argon is smaller than that of neon. A vacancy in copper can bind three helium atoms or two neon atoms, but only one argon atom. Results are compared with those obtained from thermal desorption measurements.

Some methods used for analysing thermal desorption spectra are presented. The methods can be applied to the first-order rate equation, but they are also applicable when analysing second-order spectra. The classical Arrhenius method is discussed critically. Some new formulae for the analysis are introduced. The methods utilize the peak area, peak shape or the half-width of the peak.

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We have used the thermal desorption method to study helium, neon and argon impurities in copper. Four different peaks are analysed from the helium desorption spectrum. Neon and argon spectra are more difficult to interpret. A new interpretation of the clear peaks of these spectra is given.

The magnetic flux loss induced in sintered Nd-Fe-B permanent magnets by proton and a irradiation has been measured. The irradiations have been made with 14 -20 MeV protons and with 56 MeV a particles. The dependence of the magnetic flux loss on the temperature, external magnetic field, and on the particle energy has been studied. An earlier theoretical model of the magnetic damage is refined to take into account the effects of the external magnetic field as well as the shape of the magnet sample. The good agreement between the experimental and theoretical results supports our theoretical model according to which the local heating induced by particle irradiation causes the magnetic flux loss.