[en] Assembly of the spectrometer hardware and electronics is underway. The microballoons for the main experiment have been chosen. Discussions were held with personnel at the Stanford Tandem Van de Graaff Facility in preparation for calibration of the spectrometer

[en] The general design of this spectrometer has been completed. A meeting was held at the University of Rochester to review the experiment. The delay in the completion of the spectrometer by ARACOR is expected to be 4 to 5 weeks

[en] Recent PITHON experiments with plasma erosion switches (PES) have extended the range of operation of the switches by about 50 percent, in terms of closed time and charge passing through the switch. The quantity of charge passed through the switch has been increased to as much as 35 mC. Currents as large as 1 MA and voltages as great as 1.8 MV have been switched off to be diverted to a downstream load. The impedance of the erosion switch can be described as having three stages: 1) essentially zero impedance, 2) a transitional opening phase, and 3) an impedance which is very large (greater than 5 Ω) in comparison with the subohm downstream load. Current diagnostics, consisting of Rogowski coils and segmented shunts, have been successfully developed to monitor the current which propagates to the load region. These monitors have measured rise times as short as 38 ns and slew rates as great as 10¹⁴ A/s at the load. With wire array loads, the pulse conditioning of the switch has been observed to reduce the magnitude of the current losses in the feed which are present when no switch is used. Correlations have been made between the switch closed time, voltage, current, and power with the feed inductance and the generator power injected into the magnetic insulated transmission line (MITL)

[en] The authors observed energetic ions propagating downstream of an unmagnetized relativistic reflex triode. The configuration was driven by an electrical power pulse of 1.0-2.5 MV, 60-90 kA, and 70 ns FWHM duration. The ion source was a 6 micron thick aluminized mylar anode foil, coated with LiD or LiH powders held in an acrylic matrix. Two cathode diameters, 2 cm and 6.25 cm, were used. Deuterons and protons were detected using carbon, copper, chromium, and zinc nuclear activation threshold techniques. Time resolved ion measurements were performed with Faraday cup charge collectors. A spatially resolved scintillation detector recorded the radiation pattern of activation targets. Propagation of the beam to distances beyond 2 meters was examined. The effect of anode cathode spacing, target distance, and anode preparation on the particle beam production was also examined. Both ion time-of-flight and threshold activation suggest ion energies which exceed the primary diode energy, with peak proton energies above 14 MeV. The spatial scintillation detector has indicated that the beam is divergent, with a central region of higher density having a divergence half-angle of less than 10 degrees, directed off axis approximately 10 degrees. Deuteron and proton fluxes of 10¹²-10¹³ ions were measured by activation and charge collector data

[en] A 1 μs pulse-length, high-current relativistic klystron is being developed with a desired peak output power of 1 GW at 1.3 GHz. The tube consists of an input cavity, a single idler cavity, and an output cavity. Power levels as high as 475 MW have been experimentally observed. Current experimental results are presented. Physics and engineering issues affecting klystron performance are discussed

[en] A Thomson parabola charged particle spectrometer was built with an energy resolution of 80 keV and an active silicon detector array that is read by a computer-compatible CAMAC. The instrument was checked out at the University of Rochester Omega Laser facility. Experiments to measure the ambipolar potential and the dE/dx thermonuclear target to within 50 keV are now possible. The ion temperature of the burn can be determined to within 10%

[en] Plasma erosion switches have been fielded on the PITHON generator during imploding plasma experiments. Theta pinch plasma guns were used to inject carbon plasmas of densities in the range of 10¹²--10¹⁴ cm³ between the electrodes of the vacuum power feed region, upstream from an imploding plasma load. Current monitors indicated that the erosion switches carried substantial current early in time, diverting it from the load. Late in the pulse the erosion switches opened, transferring the current to an imploding plasma with the effect of sharpening the current rise time at the load. Associated withthe sharper rise time was an improvement in the quality of the plasma implosions. The results of varying the density and total number of particles in the plasma of the switches are presented with regard to the effect on the current along the vacuum feed and on the behavior of vacuum flowing electrons

[en] The operation of a pinch-reflex diode as an intense pulsed ion-beam source has been scaled up to the multiterawatt PITHON generator. Ion beams with currents of 1 MA at 1.8 MeV have been extracted in a 130 kJ, 100-ns pulse. The corresponding ion production efficiency is 60%. Power losses were observed in interfacing the coaxial diode to the biconic vacuum feed of the generator. By using smaller area diodes, the average current density at the anode source was increased to 20 kA/cm₂. Proton and deuteron beams were studied in both planar and spherical diode geometries. The ion beam is focused predominantly by self-magnetic fields for planar diodes and predominantly by electrode shaping for spherical diodes. Current densities exceeding 150 kA/cm₂ were achieved with spherical diodes. The spatial evolution of the anode and cathode plasmas was studied by laser holographic interferometry. As the peak of the power pulse is approached, plasmas were observed to expand from the electrodes in fairly uniform profiles with steep density gradients and to accelerate across the vacuum gap. After peak power, anode plasma fluctuations and a high-velocity (30 cm/μs) axial plume develop; the latter expands radially coincident with collapse of the power pulse