This paper reports the design and development of two intermediate-velocity superconducting cavities and design of an associated cryomodule for the RIA driver linac. The two cavity types are a 115 MHz, {beta}{sub GEOM} = 0.15 quarter-wave resonant (QWR) cavity, and a 173 MHz, {beta}{sub GEOM} = 0.26 half-wave loaded cavity. Both cavities are well-corrected for dipole and quadrupole asymmetries in the accelerating field. The cryomodule is being designed to incorporate a separate vacuum system for cavity vacuum to provide a particulate-free environment for the superconducting cavities.

An analysis of available literature data on both the positive ion emission from Nb and Ta bombarded by 6 keV/atom Au{sub m}{sup -} atomic and molecular ions (m=1, 2, 3) and positive ionization probabilities of Nb{sub n} and Ta{sub n} neutral clusters sputtered from the same metals by 5 keV Ar{sup +} ions have been conducted. Dependencies of cluster yields Y{sub n,m} (regardless of a charge state) on number of atoms n in a sputtered particle were found to follow a power law as Y{sub n,m} {approx} n{sup -{sigma}{sub m}} where {sigma}{sub m} decreased with an increase of m. A non-linear enhancement of yields for large Nb{sub n}{sup +} and Ta{sub n}{sup +} cluster ions (n>4) appeared to be due to a non-additive process of sputtering rather than because of a non-additive process of their ionization. A manifestation of the non-additive sputtering in kinetic energy distributions of secondary ions found to be different for atomic and cluster ions.

The interlayer transport properties of the organic superconductor {beta}{double_prime}-(ET){sub 2}SF{sub 5}CH{sub 2}CF{sub 2}SO{sub 3} are presented. The resistivity perpendicular to the highly conducting ET layers is about 100 times larger than compared to other quasi-two-dimensional ET salts. For a magnetic field parallel to the layers no peak could be resolved in the angle-dependent interlayer resistance which proved the coherent nature of transport in other ET salts. This and the absence of any further clear-cut proof for a coherent quasiparticle motion suggest an incoherent nature of the interlayer transport in {beta}{double_prime}-(ET){sub 2}SF{sub 5}CH{sub 2}CF{sub 2}SO{sub 3}.

The authors report on the electronic transport properties of the organic superconductor {beta}{double_prime}-(ET){sub 2}SF{sub 5}CH{sub 2}CF{sub 2}SO{sub 3} at high fields and under hydrostatic pressure. With increasing pressure the superconducting transition temperature decreases in line with a decreasing effective mass. The closed Fermi-surface (FS) area increases strongly but the FS topology remains unchanged.

The driver linac for the U.S. RIA project will be a 1.4 GV superconducting linac capable of accelerating the full mass range of ions from 900 MeV protons to 400 MeV/u uranium, and delivering a cw beam of 400 kW shared by at least two targets simultaneously. Elements of the linac are being developed at several U.S. laboratories. The current status of linac design and development is reviewed with emphasis on changes in the baseline design since the last linac conference.

The effect of ExB and diamagnetic drifts on the boundary plasma of a diverted tokamak is examined by comparing simulations obtained from the 2D fluid code UEDGE with data from the DIII-D tokamak. The effect of drifts on a single null L-mode configuration is determined by comparing the measurements with two simulations which are identical except that only one includes drifts. The dominant effect is seen on the high B-field side of the divertor where the plasma density is a factor of two higher when drifts are included. This effect occurs because a radial electric field associated with steep electron temperature radial gradients along the separatrix between the X-point and strike points drives a poloidal flow from the outer to inner divertor in the private region. The higher density yields higher radiation power, moving line radiation zones further off the divertor plate. The simulated profiles of both D{sub {alpha}} and CIII radiation obtained with drift effects included are more consistent with measurements. The drifts also affect the in/out asymmetry of both divertor heating power and divertor ion flux. The effect of drifts on the up/down asymmetry of double null plasma configurations is also considered, although not in as much detail. …