  We report on trapping of fermionic 40K atoms in a red-detuned standing-wave
optical trap, loaded from a magneto-optical trap. Typically, 10^6 atoms are
loaded at a density of 10^12 cm^-3 and a temperature of 65 microK, and trapped
for more than 1 s. The optical trap appears to be the proper environment for
performing collisional measurements on the cold atomic sample. In particular we
measure the elastic collisional rate by detecting the rethermalization
following an intentional parametric heating of the atomic sample. We also
measure the inelastic two-body collisional rates for unpolarized atoms in the
ground hyperfine states, through detection of trap losses.
