A second generation EMET railgun for secondary arc studies

Since 1985 GT-Devices has been operating a pair of railguns with lengths of 0.9 m and 3.6 m, respectively. A new second-generation railgun is now being constructed to improve straightness, stiffness, sealing, and diagnostic access. The basic design consists of a steel tube with a thin lengthwise slit forming two halves in cross section with bolt preloading. The internal structure consists of split tubular G-10 compression blocks with Glidcop AL-15 rails and polycarbonate insulators formed from 90 degree tube sections. A new 0.9 m launcher of the same design is now under construction, with a 3.6 m version to follow. An upgraded electrothermal injector has been developed using modified armature injection module (AIM) hardware. Injection velocities of 2500 m/s have been attained with 1.1 gram polycarbonate projectiles for stored bank energies of 65 kJ. Injection velocities of 3000 m/s may be possible. The design details of the new railgun, injector, and diagnostics are discussed, and some initial experimental results are presented