[en] The ideas and methods used in in-beam gamma spectroscopy are surveyed. The first part deals with the methods of acquisition of gamma spectroscopic information. The features of gamma spectra expected after nuclear reactions, coincidence methods of increasing the resolution of the spectrometer and enhancement methods of weak reaction channels are described in detail. The second part discusses the methods of derivation of the nuclear state characteristics - energy, angular momentum and parity - based on the detected gamma spectrum. The mixing and branching ratios can be calculated as well. The final results can be used to test not only the matrix elements of the model Hamiltonian but the model wave functions themselves. (D.Gy.)

[en] ^{114,112,110,108,106}In nuclei were studied by in-beam gamma and electron spectroscopy in proton and alpha induced reactions. The energy splitting of proton-neutron states of ^{116,114,112,110}In and ^122,120Sb nuclei was studied using the parabolic rule derived from the cluster-vibrational model. The parabolic rule gives a good description of the known energy levels. Quantum states of ¹¹⁴In were analyzed in detail. Nuclear wave functions and magnetic dipole moments were calculated by OTQM computer code. The results are in good agreement with the experimental data. (D.Gy.)