  Measurements of the de Haas - van Alphen effect in the normal state of the
heavy Fermion superconductor CeCoIn5 have been carried out using a torque
cantilever at temperatures ranging from 20 to 500 mK and in fields up to 18
tesla. Angular dependent measurements of the extremal Fermi surface areas
reveal a more extreme two dimensional sheet than is found in either CeRhIn5 or
CeIrIn5. The effective masses of the measured frequencies range from 9 to 20
m*/m0.
