131 research outputs found

    Evaluation of the discrete vortex wake cross flow model using vector computers. Part 2: User's manual for DIVORCE

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    The users manual for the Discrete Vortex Cross flow Evaluator (DIVORCE) computer program is presented. DIVORCE was developed in FORTRAN 4 for the DCD 6600 and CDC 7600 machines. Optimal calls to a NASA vector subroutine package are provided for use with the CDC 7600

    Spin decoherence and off-resonance behavior of radiofrequency-driven spin rotations in storage rings

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    Radiofrequency-driven resonant spin rotators are routinely used as standard instruments in polarization experiments in particle and nuclear physics. Maintaining the continuous exact parametric spin-resonance condition of the equality of the spin rotator and the spin precession frequency during operation constitutes one of the challenges. We present a detailed analytic description of the impact of detuning the exact spin resonance on the vertical and the in-plane precessing components of the polarization. An important part of the formalism presented here is the consideration of experimentally relevant spin-decoherence effects. We discuss applications of the developed formalism to the interpretation of the experimental data on the novel pilot bunch approach to control the spin-resonance condition during the operation of the radiofrequency-driven Wien filter that is used as a spin rotator in the first direct deuteron electric dipole moment measurement at COSY. We emphasize the potential importance of the hitherto unexplored phase of the envelope of the horizontal polarization as an indicator of the stability of the radiofrequency-driven spin rotations in storage rings. The work presented here serves as a satellite publication to the work published concurrently on the proof of principle experiment about the so-called pilot bunch approach that was developed to provide co-magnetometry for the deuteron electric dipole moment experiment at COSY.Comment: 31 pages, 10 figures, 5 table

    Pilot bunch and co-magnetometry of polarized particles stored in a ring

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    In polarization experiments at storage rings, one of the challenges is to maintain the spin-resonance condition of a radio-frequency spin rotator with the spin-precessions of the orbiting particles. Time-dependent variations of the magnetic fields of ring elements lead to unwanted variations of the spin precession frequency. We report here on a solution to this problem by shielding (or masking) one of the bunches stored in the ring from the high-frequency fields of the spin rotator, so that the masked pilot bunch acts as a co-magnetometer for the other signal bunch, tracking fluctuations in the ring on a time scale of about one second. While the new method was developed primarily for searches of electric dipole moments of charged particles, it may have far-reaching implications for future spin physics facilities, such as the EIC and NICA.Comment: 5 pages, 3 figures + references + supplemental material (6 pages, 2 figures, 6 tables + references

    Self-healing response in supramolecular polymers based on reversible zinc–histidine interactions

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    Abstract Histidine-metal interactions are utilized in many biological materials as reinforcing crosslinks, and in particular, are believed to contribute as reversible crosslinks to the intrinsic self-recovery behavior of mussel byssal threads. In this contribution, two new histidine-based monomers were synthesized and further copolymerized with butyl methacrylate (BMA) and lauryl methacrylate (LMA) applying the reversible addition–fragmentation chain transfer (RAFT) polymerization technique. Crosslinking with zinc ions resulted in supramolecular metallopolymer networks exhibiting a self-healing behavior that was tunable depending on the specific zinc salt used. The presented results provide a class of new polymeric species with different self-healing capacities
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