Beam dynamics studies of four-gap low-beta superconducting resonators (open access)

Beam dynamics studies of four-gap low-beta superconducting resonators

The four-gap superconducting resonators which have been developed at Argonne for use in the low-beta positive ion-injector for ATLAS have potential applications for ions with velocities less than 0.007c and q/m less than 0.1. It was previously observed that at low velocities these structures can be focusing in both longitudinal and transverse phase spaces due to an inherent alternating-phase-focusing property. Studies are underway to determine the optimum combination of multi-gap structures and solenoids at low velocity and low q/m. In this paper the authors present the results of acceptance studies for the first three resonators at the front of the positive-ion injection linac, with and without the focusing solenoids. These studies include the effects of higher-order distortions in longitudinal and transverse phase spaces since minimizing such aberrations is very important for most nuclear physics applications of such accelerators.
Date: May 20, 1993
Creator: Nolen, J. A. & Joh, K.
System: The UNT Digital Library
Global emissions and models of photochemically active compounds (open access)

Global emissions and models of photochemically active compounds

Anthropogenic emissions from industrial activity, fossil fuel combustion, and biomass burning are now known to be large enough (relative to natural sources) to perturb the chemistry of vast regions of the troposphere. A goal of the IGAC Global Emissions Inventory Activity (GEIA) is to provide authoritative and reliable emissions inventories on a 1{degree} {times} 1{degree} grid. When combined with atmospheric photochemical models, these high quality emissions inventories may be used to predict the concentrations of major photochemical products. Comparison of model results with measurements of pertinent species allows us to understand whether there are major shortcomings in our understanding of tropospheric photochemistry, the budgets and transport of trace species, and their effects in the atmosphere. Through this activity, we are building the capability to make confident predictions of the future consequences of anthropogenic emissions. This paper compares IGAC recommended emissions inventories for reactive nitrogen and sulfur dioxide to those that have been in use previously. We also present results from the three-dimensional LLNL atmospheric chemistry model that show how emissions of anthropogenic nitrogen oxides might potentially affect tropospheric ozone and OH concentrations and how emissions of anthropogenic sulfur increase sulfate aerosol loadings.
Date: May 20, 1993
Creator: Penner, J. E.; Atherton, C. S. & Graedel, T. E.
System: The UNT Digital Library