  We present a detailed experimental study of a three-dimensional lin$\perp$lin
bright optical lattice. Measurements of the atomic temperature and spatial
diffusion coefficients are reported for different angles between the lattice
beams, i.e. for different lattice constants. The experimental findings are
interpretated with the help of numerical simulations. In particular we show,
both experimentally and theoretically, that the temperature is independent of
the lattice constant.
