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An available supply of high-specific-activity radioisotopes was identified by the U.S. Department of Energy as a critical priority in the development and eventual deployment of next-generation medical diagnostic and cancer therapy tools. A radioisotope mass separator, located at the Missouri University Research Reactor Center, was developed to provide radioactive ion beams for the separation and production of high-specific-activity lanthanides used in radiopharmacology. Experiments characterizing the ionization efficiency of a thermal ion source supporting the production of high-specific-activity 153Sm are reported. With the goal of maximizing ion current while maintaining beam stability, experiments with the test ion source expand upon previously reported data from a titanium prototype ion source. Experimental results of various factors affecting ion source performance, such as diameter of the extraction orifice, ionizer geometry, ionizer temperature, and sample evaporation rate, are presented. [ABSTRACT FROM AUTHOR]

An available supply of high-specific-activity radioisotopes was identified by the U.S. Department of Energy as a critical priority to the development and eventual deployment of next-generation medical diagnostic and cancer therapy tools. Work at the University of Missouri Research Reactor Center has been undertaken to develop an electromagnetic isotope separation technique that will leverage the production capabilities of the 10-MW reactor to provide radiolanthanides in quantities suitable for use in preclinical trials. A high-throughput concept design based on a solid tantalum hot surface ion source and an insertable titanium crucible will be described. Significant aspects of the electrical and thermal design of the ion source will be presented. Novel heating and cooling strategies were employed to concentrate heating where it is most needed while attempting to reduce thermal stress where heating is not required. Thermal testing from the commissioning process will be presented to demonstrate the temperature at several key locations in and around the ion source. [ABSTRACT FROM AUTHOR]

A high-pressure oil switch for high-energy systems has been developed and tested to repetition rates up to 100 pps in burst mode and test voltages to -300 kV. The switch utilizes high-pressure flowing synthetic oil and advanced mechanical designs to achieve high-performance operation at pressures to 17.24 MPa (2500 psi). Experimental data is presented for both single-shot performance as well as continuous repetition rate performance to 20 pps. Electrode lifetime is evaluated for stainless steel and Elkonite to demonstrate electrode lifetime. Evidence is presented in support of the dependence of switching performance on the geometry of the switch. Index Terms--High pressure, high-voltage switch, liquid dielectric, oil switch, rep-rate switch.

The high output voltages from piezoelectric transformers are currently being used to accelerate charged particle beams for x-ray and neutron production. Traditional methods of characterizing piezoelectric transformers (PTs) using electrical probes can decrease the voltage transformation ratio of the device due to the introduction of load impedances on the order of hundreds of kiloohms to hundreds of megaohms. Consequently, an optical diagnostic was developed that used the photoelastic and electro-optic effects present in piezoelectric materials that are transparent to a given optical wavelength to determine the internal stress and electric field. The combined effects of the piezoelectric, photoelastic, and electro-optic effects result in a time-dependent change the refractive indices of the material and produce an artificially induced, time-dependent birefringence in the piezoelectric material. This induced time-dependent birefringence results in a change in the relative phase difference between the ordinary and extraordinary wave components of a helium-neon laser beam. The change in phase difference between the wave components was measured using a set of linear polarizers. The measured change in phase difference was used to calculate the stress and electric field based on the nonlinear optical properties, the piezoelectric constitutive equations, and the boundary conditions of the PT. Maximum stresses of approximately 10 MPa and electric fields of as high as 6 kV/cm were measured with the optical diagnostic. Measured results were compared to results from both a simple one-dimensional (1D) model of the piezoelectric transformer and a three-dimensional (3D) finite element model. Measured stresses and electric fields along the length of an operating length-extensional PT for two different electrical loads were within at least 50 % of 3D finite element simulated results. Additionally, the 3D finite element results were more accurate than the results from the 1D model for a wider range of electrical load impedances under test. [ABSTRACT FROM AUTHOR]

A high-pressure oil switch for high-energy systems has been developed and tested to repetition rates up to 100 pps in burst mode and test voltages to -300 kV. The switch utilizes high-pressure flowing synthetic oil and advanced mechanical designs to achieve high-performance operation at pressures to 17.24 MPa (2500 psi). Experimental data is presented for both single-shot performance as well as continuous repetition rate performance to 20 pps. Electrode lifetime is evaluated for stainless steel and Elkonite to demonstrate electrode lifetime. Evidence is presented in support of the dependence of switching performance on the geometry of the switch. [ABSTRACT FROM AUTHOR]