An X-band tunnel diode amplifier (TDA) has been studied for SGEMP response. This study has involved analytical modeling and predictions, tunnel diode electrical pulsing to develop damage statistics, and experimental measurements in an 800 kvp flash X-ray environment. In contrast to photocurrent limited TREE response, significant SGEMP replacement currents can flow through the tunnel diode. This response is associated with mechanical design, the use of gold-plated conductors facing aluminum surfaces within a cavity with corresponding photoemission differences and the differences in fore and back emission between the tunnel diode amplifier and the evacuated test chamber walls. The SGEMP current is independent of bias circuit design. The modeling and prediction effort included SGEMP current determination, electrical circuit modeling and computerized transient radiation circuit analysis. The experimental SGEMP tests were performed in vacuum using the BLACK-JACK 3 (BJ3) facility at Maxwell Laboratories, Inc., in San Diego, California. Measurements are reported for the current responses of the tunnel diode and the circulator. Eight tunnel diodes were damaged due to SGEMP and their damage threshold energies were calculated, using tunnel diode characteristics, radiation dose and SGEMP currents. Damage frequency data for the BJ3 tests correlates with separate electrical pulse data and supports the conclusion that the SGEMP response of TDA's is predictable using the model developed in this study.