Daniel Lowe

Lanthanum halide nanoparticle scintillators for nuclear radiation detection

Nanoparticles with sizes <10 nm were fabricated and characterized for their nanocomposite radiation detector properties. This work investigated the properties of several nanostructured radiation scintillators, in order to determine the viability of using scintillators employing nanostructured lanthanum trifluoride. Preliminary results of this investigation are consistent with the idea that these materials have an intrinsic response to nuclear radiation that may be correlated to the energy of the incident radiation.

PPPS-2013: Observed multi-decade DD and DT Z-pinch fusion rate scaling in 5 Dense Plasma Focus fusion machines

Summary form only given. Dense Plasma Focus (DPF) machines are in use worldwide for a wide variety of applications; one of these is to produce intense, short bursts of fusion via r-Z pinch heating and compression of a working gas. We have designed and constructed a series of these, ranging from portable to a maximum energy storage capacity of 2 MJ. Fusion rates from 5 DPF pulsed fusion generators have been measured in a single laboratory using calibrated activation detectors. Measured rates range from ~ 1015 to more than 1019 fusions per second have been measured. Fusion rates from the intense short (20-50 ns) periods of production were inferred from measurement of neutron production using both calibrated activation detectors and scintillator-PMT neutron time of flight (NTOF) detectors. The NTOF detectors are arranged to measure neutrons versus time over flight paths of 30 Meters. Fusion rate scaling versus energy and current will be discussed. Data showing observed fusion cutoff at D-D fusion yield levels of approximately 1*1012, and corresponding tube currents of ~ 3 MA will be shown. Energy asymmetry of product neutrons will also be discussed. Data from the NTOF lines of sight have been used to measure energy asymmetries of the fusion neutrons. From this, center of mass energies for the D(d,n)3He reaction are inferred. A novel re-entrant chamber that allows extremely high single pulse neutron doses (> 109 neutrons/cm2 in 50 ns) to be supplied to samples will be described. Machine characteristics and detector types will be discussed.

Measurements of Dense Plasma Focus performance with both deuterium and deuterium-tritium gasses

Summary form only given. NSTec has constructed and is operating several Dense Plasma Focus devices, with capacitor bank sizes ranging from a kilojoule to 2 megajoules. Most have been fueled with deuterium. A new machine has been designed and brought into operation with deuterium - tritium as fuel. An overview of this family of DPF sources will be presented, followed by a discussion of initial results and conclusions from the startup of the new deuterium-tritium fueled Dense Plasma Focus.The new source has a full-voltage energy capacity of 700 kJ, is typically operated with stored energies of 200-350 kJ, at voltages between 25 and 35 kV producing total currents of ≥2 million amperes, and 14 MeV yields of up to 1013 neutrons/pulse.Comparisons of features of DD and DT operation of this machine will be presented, including the observed ratio of deuterium neutron yield to deuterium-tritium neutron yield, measurements of reaction duration for DD and DT fuels measured by PMT-flour and diamond detectors, inferred beam target ion energies, energy and fluence anisotropy, and some factors governing observed neutron timeof-flight peak shapes.