No abstract available

[en] The supersymmetric SU(3)xSU(2)xU(1) theory with minimal particle content and general soft supersymmetry breaking terms has 110 physical parameters in its flavor sector: 30 masses, 39 real mixing angles and 41 phases. The absence of an experimental indication for the plethora of new parameters places severe constraints on theories possessing Planck- or GUT-mass particles and suggests that theories of flavor conflict with naturalness. We illustrate the problem by studying the processes μ→e + γ and K⁰ - K⁰ mixing which are very sensitive probes of Planckian physics: a single Planck-mass particle coupled to the electron or the muon with a Yukawa coupling comparable to the gauge coupling typically leads to a rate for μ→e + γ exceeding the present experimental limits. A possible solution is that the messengers which transmit supersymmetry breaking to the ordinary particles are much lighter than M_Pl. (orig.)

[en] The purpose of the meeting was to discuss and develop cost-estimating methods for heavy-ion fusion accelerator systems. The group did not consider that its purpose was to make technical judgements on proposed systems, but to develop methods for making reasonable cost estimates of these systems. Such estimates will, it is hoped, provide material for systems studies, will help in guiding research and development efforts by identifying ''high-leverage'' subsystems (areas that account for a significant part of total system cost and that might be reduced in cost by further technical development) and to begin to provide data to aid in an eventual decision on the optimum type of accelerator for heavy-ion fusion

[en] The purpose of the meeting was to discuss and develop cost-estimating methods for heavy-ion fusion accelerator systems. The group did not consider that its purpose was to make technical judgments on proposed systems, but to develop methods for making reasonable cost estimates of these systems. Such estimates will, it is hoped, provide material for systems studies, will help in guiding research and development efforts by identifying high-leverage subsystems (areas that account for a significant part of total system cost and that might be reduced in cost by further technical development) and to begin to provide data to aid in an eventual decision on the optimum type of accelerator for heavy-ion fusion. The systems considered as examples are: (1) injection system; (2) Wideroe linac; (3) Alvarez linac; (4) induction linac; (5) superconducting accumulator ring; (6) synchrotron; (7) final rf bunching; and (8) final beam transport to target

[en] The hydrogen jet target, a product of joint USSR-USA research, replaces conventional foil targets for proton-proton interactions in the main accelerator of the National Accelerator Laboratory. Cryogenic systems are necessary both to prepare the jet target and to maintain the accelerator vacuum against the introduction of hydrogen gas pulses. (U.S.)

[en] The University of Maryland Electron Ring (UMER) is a unique machine that uses scaled electron beams at nonrelativistic energies (10 keV) to inexpensively model GeV beams of heavy ions over long path lengths (kilometers of transport distance). The UMER beam parameters correspond to space charge tune depressions, at injection, adjustable in the range of 0.14–0.85. Although a ring, many of the intense beam studies on UMER are applicable to linacs. This paper reviews the UMER program, which contains experimental, computational, and theoretical components. We outline the research areas of interest, recent accomplishments, and future plans, emphasizing the relevance to heavy ion drivers. Specific topics include longitudinal induction focusing and beam manipulations; generation and propagation of space charge waves, including large-amplitude solitons; bunch end interpenetration and observation of a multi-stream instability; beam halo studies; and diagnostic development

[en] An induction cell has successfully been demonstrated to longitudinally confine a space-charge dominated bunch for over a thousand turns (>11.52 km) in the University of Maryland Electron Ring [Haber et al., Nucl. Instrum. Methods Phys. Res. A 606, 64 (2009) and R. A. Kishek et al., Int. J. Mod. Phys. A 22, 3838 (2007)]. With the use of synchronized periodic focusing fields, the beam is confined for multiple turns overcoming the longitudinal space-charge forces. Experimental results show that an optimum longitudinal match is obtained when the focusing frequency for containment of the 0.52 mA beam is applied at every fifth turn. Containment of the beam bunch is achievable at lower focusing frequencies, at the cost of a reduction in the transported charge from the lack of sufficient focusing. Containment is also obtainable, if the confinement fields overfocus the bunch, exciting multiple waves at the bunch ends, which propagate into the central region of the beam, distorting the overall constant current beam shape.

[en] The University of Maryland Electron Ring (UMER) is now operational. UMER can operate with currents from 0.6 mA to 100 mA, ranging from the emittance dominated to the heavily space charge dominated regimes. Multiple turns have been achieved at all operating currents, from 250 turns at 0.6 mA to about 12 turns at 100 mA, but not yet optimized for operation above 25 mA. Machine development in the past year has been on understanding the single particle behavior in order to establish a strong basis for studying the effects of space charge. The effect of the earth's field has been studied and compensation implemented. Basic machine parameters such as the tune, equilibrium orbit, chromaticity and dispersion have been measured over a range of currents. We report here on these measurements and corresponding simulations.

[en] The study of the electromagnetic moments, and decay probability, provides detailed information about nuclear wave functions. The well-know structure of the E M interactions are good for extracting information about the properties of the individual nucleons. However, the lowest multipoles are not always the only ones included in the decay process. It has been observed previously in the case of a 0+ →0+ transitions, where a single gamma transition is forbidden, the simultaneous emission of two γ rays. A great opportunity to further investigate this phenomena is by using the standard 137Cs source populating via β-decay the isomeric state at 662 keV in 137Ba. In this case two photon process can have contributions from quadrupole-quadrupole or dipole-octupole multipolarities due to the high multipolarity of the decay, M4. Since the yield of the double gamma decay is around 10-6 orders of magnitude less than the first order transition very good statistics are needed in order to observe the phenomena. Using Gamma sphere is ideal since its configuration allows a good coverage of the angular distribution and the Compton events can be suppressed. Nevertheless the process to understand and eliminate the Compton background is a challenge. GEANT4 simulations were carried out to help correct for those factors. A new direct cascade via the low-lying Jπ = 1/2+ has been found

[en] An alternative concept for Heavy Ion Inertial Fusion (HIF) is the use of a recirculator to accelerate ion beams to energies in the range of 50-100 GeV. The physics of an ion recirculator can be explored by means of scaled experiments in a compact machine like the existing University of Maryland Electron Ring (UMER). UMER has been successfully used for the study of the fundamental physics of space-charge-dominated transport using a 10 keV electron beam with up to 100 mA of current (or 10 nC per a 100 ns pulse). Due to the low energy and high perveance, the UMER beam accesses the same range of intensities as an HIF driver. In this paper we report on a computational study for the design of an acceleration stage for UMER using an induction cell. Using the two-dimensional transverse slice model in the particle-in-cell code WARP we show that it is possible to accelerate the UMER beam up to 20 keV without major modifications to the machine. Such acceleration enables future experiments on transverse resonance crossing and studies on longitudinal pulse behavior.