  We review a method that we recently introduced to calculate the
finite-temperature distribution of the axial quadrupole operator in the
laboratory frame using the auxiliary-field Monte Carlo technique in the
framework of the configuration-interaction shell model. We also discuss recent
work to determine the probability distribution of the quadrupole shape tensor
as a function of intrinsic deformation $\beta,\gamma$ by expanding its
logarithm in quadrupole invariants. We demonstrate our method for an isotope
chain of samarium nuclei whose ground states describe a crossover from
spherical to deformed shapes.
