  We irradiate the heavy fermion superconductors (U,Th)Be_13 with high-energy
heavy ions. Damage from the ions affects both heat capacity and magnetization
measurements, although much less dramatically than in other superconductors.
  From these data and from direct imaging, we conclude that the irradiation
does not create the amorphous columnar defects observed in high-temperature
superconductors and other materials. We also find that the damage suppresses
the two superconducting transitions of U_0.97Th_0.03Be_13 by comparable
amounts, unlike their response to other types of defects.
