We summarize and critically evaluate the available data on nuclear fusion cross sections important to energy generation in the Sun and other hydrogen-burning stars and to solar neutrino production. Recommended values and uncertainties are provided for key cross sections, and a recommended spectrum is given for 8 B solar neutrinos. We also discuss opportunities for further increasing the precision of key rates, including new facilities, new experimental techniques, and improvements in theory. This review, which summarizes the conclusions of a workshop held at the Institute for Nuclear Theory, Seattle, in January 2009, is intended as a 10-year update and supplement to Reviews of Modern Physics 70 (1998) 1265.

The design of the Spallation Neutron Source (SNS) prototype low-energy beam transport (LEBT) system is discussed. This LEBT must transfer 35 mA of H -current from the ion source outlet aperture to the entrance of the radio-frequency quadrupole (RFQ). The plasma generator is a radio frequency-driven multicusp source, operated at 6% duty factor (1 ms, 60 Hz). The entire LEBT configuration is electrostatic, with a high-voltage extraction gap followed by two sets of einzel lenses. The second einzel lens will be split into four quadrants to permit the application of transverse steering and beam chopping fields. The H -ion source emits a gas flow into the LEBT that must be efficiently pumped to reduce stripping losses of the H -ions. Therefore, an efficient electrode design is incorporated to reduce the gas pressure between the electrodes. Alignment requirements and related issues will also be discussed.

Thermonuclear reaction cross sections of astrophysical interest decrease exponentially with energy, approaching the level of femtobarn or less at the Gamow window. Experimental investigations of such small reaction rates in laboratories at the earth's surface are hampered by the cosmic-ray background into detectors. For such studies, Dakota Ion Accelerator for Nuclear Astrophysics, a deep underground, high detector efficiency, high target density, high beam intensity accelerator facility is being designed. We report on a 100 mA, 400 kV accelerator design. To take into account the beam space-charge effects, advanced three-dimensional transportation calculations have been performed. These highly realistic beam calculations demonstrate that high beam currents can be transported to a gas-jet target with a diameter of few millimeters.

The ion source for the 1 MW National Spallation Neutron Source (NSNS) is required to provide 35 mA of H- beam current (1 ms pulses at 60 Hz) at 65 keV with a normalized root-mean-square emittance of <0.2 pi mm mrad. The same ion source should be able to produce 70 mA of H- at 6% duty factor when the NSNS is upgraded to 2 MW of power. For this application, a radio-frequency driven, magnetically filtered multicusp source is being developed at Lawrence Berkeley National Laboratory. The design of this R and D ion source, which is equipped with a cesium dispenser-collar, a fast ion beam prechopper (rise times <100 ns) and a strong permanent-magnet insert for electron deflection, will be presented.

Abstract. Compact mono-energetic photon sources are sought for active interrogation systems to detect shielded special nuclear materials in, for example, cargo containers, trucks and other vehicles. A prototype gamma interrogation source has been designed and built that utilizes the 11 B(p,γ) 12 C reaction to produce 12 MeV gamma-rays which are near the peak of the photofission cross section. In particular, the 11 B(p,γ) 12 C resonance at 163 kV allows the production of gammas at low proton acceleration voltages, thus keeping the design of a gamma generator comparatively small and simple. A coaxial design has been adopted with a toroidal-shaped plasma chamber surrounding a cylindrical gamma production target. The plasma discharge is driven by a 2 MHz rf-power supply (capable up to 50 kW) using a circular rfantenna. Permanent magnets embedded in the walls of the plasma chamber generate a multi-cusp field that confines the plasma and allows higher plasma densities and lower gas pressures. About 100 proton beamlets are extracted through a slotted plasma electrode towards the target at the center of the device that is at a negative 180 kV. The target consists of LaB 6 tiles that are brazed to a water-cooled cylindrical structure. The generator is designed to operate at 500 Hz with 20 µs long pulses, and a 1% duty factor by pulsing the ion source rf-power. A first-generation coaxial gamma source has been built for low duty factor experiments and testing.