Astrophysical aspects of neutron physics

Modern ideas of the evolution of the early universe are presented, and then the scenarios of the formation and evolution of stars and the processes go verning nuclear reactions occurring in stars, including nucleosynthesis, ar e described. Particular attention is given to the production of elements th at are heavier than iron by a successive capture of neutrons (s and r proce sses); to calculate these reactions, detailed data are required on the cros s sections for (n, gamma) reactions averaged over the Maxwellian spectra of neutrons at temperatures on the order of 10-100 keV. The most important re actions are those with small cross sections and/or with excited and unstabl e nuclei. The existing experimental setups and those being developed at the Institute for Nuclear Research (Russian Academy of Sciences) and the Labor atory of Neutron Physics of JINR for measuring these reactions are describe d.