Lifetime measurement of He$^-$ and Be$^-$ using an electrostatic ion trap D. Zajfman$^1$, O. Heber$^1$, K. G. Bhushan$^1$, L. Knoll$^2$, A. Wolf$^2$, I. Ben Itzhak$^3$, and M. L. Rappaport$^1$ $^1$Department of Particle Physics, Weizmann Institute of Science, Rehovot, 76100, Israel $^2$Max-Planck-Institut f\"ur Kernphysik, D--69029 Heidelberg, Germany $^3$J. R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, KS 66506. The lifetime of He$^-$ and Be$^-$ are measured using an electrostatic ion trap which avoids the complication due to the presence of magnetic fields in heavy-ion storage rings.