A low energy accumulation stage for a beta-beam facility

The EU supported EURISOL Design Study encompasses a beta-beam facility for neutrino physics. Intense electron (anti-)neutrino beams are in such a machine generated through the decay of radioactive ions in a high energy storage ring. The two main candidate isotopes for the generation of a neutrino and an antineutrino beam are 6He and 18Ne. The intensities required are hard to reach, in particular for the neon case. A possible solution to increase the intensity is to use an accumulator ring with an electron cooler. Critical parameters such as cooling times and current limitations due to space charge and tune shifts are presently being optimized. We will in this presentation give an overview of the low energy accumulation stage and review recent work on this option

Evidence of Wave-Particle Duality for Single Fast Hydrogen Atoms

We report the direct observation of interference effects in a Young\u27s double-slit experiment where the interfering waves are two spatially separated components of the de Broglie wave of single 1.3 MeV hydrogen atoms formed close to either target nucleus in H++H2 electron-transfer collisions. Quantum interference strongly influences the results even though the hydrogen atoms have a de Broglie wavelength, λdB, as small as 25 fm

Doing the Right Things or Doing Things Right? : Paradoxes and Swedish Communication Professionals’ Roles and Challenges

Purpose – The purpose of this paper is to examine and analyze the prevailing form of rationality that governs the challenges, goals and roles of communication professionals. The authors will also explore alternative forms of rationality and discuss what these would imply. Design/methodology/approach – The paper is based on survey results from The European Communication Monitor (ECM) and qualitative interviews with communication managers in Sweden. First, the authors present the ECM data and the Swedish interview material, i.e. the authors depict the practitioners’ perceptions of what they understand as important work tasks and roles. The interviews focus on the actual practices of linking communication goals to business goals. Second, the results are challenged from a reflexive perspective, using theories from the paradox turn and questioning the “taken-for-granted thinking” in corporate communications. Findings – The ECM data show that the main challenge in practice is “linking business strategy and communication.” The Swedish respondents stand out when it comes to “building and maintaining trust” since this is considered to be almost as important. The qualitative interview study strengthens the results in the ECM. The interviewees seem to do their work according to the traditional management agenda – i.e. they break down overall business goals and translate these to measurable communication goals. The results are reflected upon using paradox theory. Two paradoxes are discussed: between managerialism and professionalism, and strategic generalists and operational specialists. Research limitations/implications – The study is based on survey data that have been collected through a convenience sample, and the interview study is a pilot study. Practical implications – The paper focuses conflicts between normative practitioner ideals and reality, and helps practitioners to reflect upon mainstream thinking. Originality/value – Based on the empirical findings in the ECM, the interviews and the theoretical framework, the authors conclude that if the idea of The Communicative Organization is to be fruitfully realized, it is necessary to depart from a multi-dimensional rationality and question ideas that are taken for granted. The use of paradox theory and concepts such as functional stupidity is rather original in corporate communication research. Additional research could further explore paradoxes in order to spark dialogue, which may undermine one-dimensional thinking and functional stupidity

Two-site double-core-hole states formed when fast protons capture electrons from aligned N2

We report on an experimental investigation of 1.04 MeV H++N2 electron transfer collisions. The fast protons were stored in the electron-cooler ion-storage ring, CRYRING and the molecular nitrogen target was provided with a supersonic gas jet. We report momentum distributions of atomic nitrogen dissociation products Nq+ with charge states q+ (q=1, 2, 3) which are detected in coincidence with neutralized projectiles. Further, we investigate the influence of the angle between the direction of the incoming projectile beam and the target molecular axis. The orientation of the latter is determined a posteriorly from the momentum vector of one emitted atomic nitrogen fragment ion. We find signicantly higher total yields, dominated by N+, of charged atomic dissociation products when the N2 molecular axis is perpendicular to the incoming H+-beam. The relative contributions from N2+- and N3+- fragments, however, are strongest when the N2 axis is aligned -or close to aligned- with the ion beam. This, we suggest, is due to increased probabilities for formation of two-site double-core-hole states

Experimental Separation of the Thomas Charge-Transfer Process in High-Velocity p-He Collisions

We present differential cross sections of electron capture in 7.5 MeV and 12.5 MeV proton-helium collisions. Complete experimental separations of the Thomas and the kinematic single electron capture processes in the two-dimensional He+ momentum distribution in the plane perpendicular to the fast ion beam have been achieved. We compare the resulting projectile angular differential cross section with the two most recent theoretical calculations and expose significant deviations

State-Resolved Mutual Neutralization of Mg+ and D-

We present experimental final-state distributions for Mg atoms formed in Mg+ + D- mutual neutralization reactions at center-of-mass collision energies of 59 +/- 12 meV by using the merged-beams method. Comparisons with available full-quantum results reveal large discrepancies and a previously underestimated total rate coefficient by up to a factor of 2 in the 0-1 eV (< 10(4) K) regime. Asymptotic model calculations arc shown to describe the process much better and we recommend applying this method to more complex iron group systems; data that is of urgent need in stellar spectral modeling

Final-state-resolved mutual neutralization of Na+ and D-

The present paper reports on a merged-beam experiment on mutual neutralization between Na+ and D-. For this experiment, we have used the DESIREE ion-beams storage-ring facility. The reaction products are detected using a position- and time-sensitive detector, which ideally allows for determination of the population of each individual quantum state in the final atomic systems. Here, the 4s, 3d, and 4p final states in Na are observed and in all cases the D atom is in its ground state 1s S-2. The respective branching fractions of the states populated in Na are determined by fitting results from a Monte Carlo simulation of the experiment to the measured data. The center-of-mass collision energy is controlled using a set of biased drift tubes, and the branching fractions are measured for energies between 80 meV and 393 meV. The resulting branching fractions are found to agree qualitatively with the only available theoretical calculations for this particular system, which are based on a multichannel Landau-Zener approach using dynamic couplings determined with a linear combination of atomic orbitals model

Importance of Thomas Single-Electron Transfer in Fast p-He Collisions

We report experimental angular differential cross sections for nonradiative single-electron capture in p-He collisions (p+ He → H + He+) with a separate peak at the 0.47 mrad Thomas scattering angle for energies in the 1.3-12.5 MeV range. We find that the intensity of this peak scales with the projectile velocity as vP-11. This constitutes the first experimental test of the prediction from 1927 by L. H. Thomas [Proc. R. Soc. 114, 561 (1927)]. At our highest energy, the peak at the Thomas angle contributes with 13.5% to the total integrated nonradiative single-electron capture cross section

Two-Center Double-Capture Interference in Fast H e²⁺+ H₂ Collisions

We report the first observation of Young-type interference effects in a two-electron transfer process. These effects change strongly as the projectile velocity changes in fast (1.2 and 2.0 MeV) He2++H2 collisions as manifested in strong variations of the double-electron capture rates with the H2 orientation. This is consistent with fully quantum mechanical calculations, which ignore sequential electron transfer, and a simple projectile de Broglie wave picture assuming that two-electron transfer probabilities are higher in collisions where the projectile passes close to either one of the H2 nuclei