Leo J. Bitteker

Proton-induced cross sections relevant to production of 225Ac and 223Ra in natural thorium targets below 200 MeV

Cross sections for (223,)(225)Ra, (225)Ac and (227)Th production by the proton bombardment of natural thorium targets were measured at proton energies below 200 MeV. Our measurements are in good agreement with previously published data and offer a complete excitation function for (223,)(225)Ra in the energy range above 90 MeV. Comparison of theoretical predictions with the experimental data shows reasonable-to-good agreement. Results indicate that accelerator-based production of (225)Ac and (223)Ra below 200 MeV is a viable production method.

225Ac and 223Ra production via 800 MeV proton irradiation of natural thorium targets

Cross sections for the formation of (225,227)Ac, (223,225)Ra, and (227)Th via the proton bombardment of natural thorium targets were measured at a nominal proton energy of 800 MeV. No earlier experimental cross section data for the production of (223,225)Ra, (227)Ac and (227)Th by this method were found in the literature. A comparison of theoretical predictions with the experimental data shows agreement within a factor of two. Results indicate that accelerator-based production of (225)Ac and (223)Ra is a viable production method.

Ac, La, and Ce radioimpurities in 225Ac produced in 40–200 MeV proton irradiations of thorium

Abstract Accelerator production of 225Ac addresses the global supply deficiency currently inhibiting clinical trials from establishing 225Acs therapeutic utility, provided that the accelerator product is of sufficient radionuclidic purity for patient use. Two proton activation experiments utilizing the stacked foil technique between 40 and 200 MeV were employed to study the likely co-formation of radionuclides expected to be especially challenging to separate from 225Ac. Foils were assayed by nondestructive γ-spectroscopy and by α-spectroscopy of chemically processed target material. Nuclear formation cross sections for the radionuclides 226Ac and 227Ac as well as lower lanthanide radioisotopes 139Ce, 141Ce, 143Ce, and 140La whose elemental ionic radii closely match that of actinium were measured and are reported. The predictions of the latest MCNP6 event generators are compared with measured data, as they permit estimation of the formation rates of other radionuclides whose decay emissions are not clearly discerned in the complex spectra collected from 232Th(p,x) fission product mixtures.

Cross sections from proton irradiation of thorium at 800 MeV

Nuclear formation cross sections are reported for 65 nuclides produced from 800-MeV proton irradiation of thorium foils. These data are useful as benchmarks for computational predictions in the ongoing process of theoretical code development and also to the design of spallation-based radioisotope production currently being considered for multiple radiotherapeutic pharmaceutical agents. Measured data are compared with the predictions of three MCNP6 event generators and used to evaluate the potential for 800-MeV productions of radioisotopes of interest for medical radiotherapy. In only a few instances code predictions are discrepant from measured values by more than a factor of two, demonstrating satisfactory predictive power across a large mass range. Similarly, agreement between measurements presented here and those previously reported is good, lending credibility to predictions of target yields and radioimpurities for high-energy accelerator-produced radionuclides.

Nuclear-induced electrical conductivity in 3He

The results of a computational and experimental investigation of nuclear-induced electrical conductivity enhancement in 3He is discussed with application to magnetohydrodynamic (MHD) energy conversion. Calculations based on the standard model of interactions and conductivity in a gas of partially ionized 3He suggest a region of conditions not previously considered may provide significant conductivity enhancement. Specifically, at densities less than standard atmospheric density and neutron flux greater than 1×1012/cm2 s, conductivity greater than 10 mho/m may be achievable. These calculations also suggest conductivities of several hundred mho/m may be possible for an achievable range of conditions. Additionally, the calculations show that nuclear-induced conductivity is strongly density dependent and weakly temperature dependent. Therefore, higher flow velocities, and hence higher power densities than those typical in traditional MHD channels utilizing thermal ionization would be possible. Experiments wer...

Learning Team Review 2016-0002 Parking Lot Event 2016

The purpose of a Learning Team is to transfer and communicate the information into operational feedback and improvement. We want to pay attention to the small things that go wrong because they are often early warning signals and may provide insight into the health of the whole system. The incident involved the collision of a van with a forklift having raised tines in rainy, overcast weather.

2012-13 Blue Room Low Enriched Uranium Sample Irradiation, Associated Gas Handling System, and Subsequent Separation Chemistry

Author(s): May, Iain; Anderson, Aaron S.; Bitteker, Leo J. Jr.; Connors, Michael A.; Copping, Roy; Cover, Matthew; Crooks, William J.; Dale, Gregory E.; Dalmas, Dale A.; Gallegos, Michael J.; Garcia, Eduardo; Gioia, Jack G.; Gonzales, Robert; Graves, Debra; Hollis, W. Kirk; Janicke, Michael T.; Kelsey, Charles T. IV; Mocko, Michal; Pieck, Martin; Rawool-Sullivan, Mohini; Reilly, Sean D.; Rios, Daniel; Romero, Tobias J.; Stephens, Francis H.; Taw, Felicia L.; Thorn, David L.; Woloshun, Keith A.