Staged Z-pinch Experiments at the 1MA Zebra pulsed-power generator: Neutron measurements

We report on neutron measurements from the latest Staged Z-pinch experiments at the 1MA Zebra pulsed-power generator. In these experiments a hollow shell of argon or krypton gas liner, injected between the 1 cm anode-cathode gap, compresses a deuterium plasma target of varying density. Axial magnetic field $B_z \le 2 kGs$, applied throughout the pinch region, stabilizes the Rayleigh-Taylor instability. The standard silver activation diagnostics and 4 plastic scintillator neutron Time of Flight (nTOF) detectors are augmented with a large area ($\sim 1400cm^2$) liquid scintillator detector to which fast \it gated \rm Photek photomultipliers are attached. Sample data from these neutron diagnostics systems is presented. Consistently high neutron yields $Y_{DD} > 10^9$ are measured, with highest yield of $2.6 \times 10^9$. A pair of horizontally and vertically placed plastic scintillator nTOFs suggest isotropic i.e. thermonuclear origin of the neutrons produced. nTOF data from the liquid scintillator detector was cross-calibrated with the silver activation detector, and can be used for accurate calculation of the neutron yield.