  When studied by small-angle neutron scattering the vortex lattice (VL) in
UPt3 undergoes a gradual disordering as a function of time due to 235U fission.
This temporarily heats regions of the sample above the critical temperature,
where, upon re-cooling, the vortices remain in a quenched vortex glass state.
The disordering rate is proportional to the magnetic field, suggesting that it
is governed by collective VL properties such as the elastic moduli. An ordered
VL can be re-formed by applying a small field oscillation, showing that the
fission does not cause significant radiation damage to the UPt3 crystals, even
after long exposure.
