  A novel method to compute time eigenvalues of neutron transport problems is
presented based on solutions to the time dependent transport equation. Using
these solutions we use the dynamic mode decomposition (DMD) to form an
approximate transport operator. This approximate operator has eigenvalues that
can be directly related to the time eigenvalues of the neutron transport
equation. This approach works for systems of any level of criticality and does
not require the user to have estimates for the eigenvalues. Numerical results
are presented for homogeneous and heterogeneous media. The numerical results
indicate that the method finds the eigenvalues that are most important to the
solution evolution over a given time range, and the eigenvalue with the largest
real part is not necessarily important to the system evolution.
