Results 1 - 10 of 20440
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[en] Measurement of the beam quadrupole moment at several locations can be used to reconstruct the beam envelope and emittance parameters. The measurements can be performed in a non-intercepting way using a set of quadrupole-mode cavities. We present a cavity design with an optimized quadrupole moment shunt impedance. The cavity properties can be characterized using a wire test method to insure symmetry about the central axis, and alignment to nearby position sensing cavities. The design and characterization of the prototype structure is discussed
[en] In this work, we present the first tuning result of the RFQ for the Proton Engineering Frontier Project (PEFP). We have adopted the TRASCO tuning method in oder to control the quadrupole and dipole field. After 4 tuning steps, we have got the dipole components to be less than ±2% of the quadrupole component
[en] During the beginning of Run II of the Tevatron Collider it became apparent that a large skew quadrupole source, or sources, had developed in the superconducting synchrotron. Efforts to locate the current source of coupling were undertaken, with the eventual discovery that the main magnets had developed a systematic skew quadrupole moment over their lifetime. Over the past year, the magnets have been altered in place in an attempt to restore the systematic skew quadrupole moment to zero. Beam observations and their interpretations are presented, and remedial measures are discussed
[en] New features have been put into the design of RFQ accelerators, which result in small emittance growth, reduce the length of the RFQ structure and can be used to improve the matching to the following linac, buncher, chopper or funneling line. Design examples are presented for the new high current linac at GSI, for the ESS study, and for the HIIF injectors. (author)
[en] This paper introduces a new kind of technology of detection, technology of NQR detection. The paper summarizes the principle, application and history of NQR detection. Then introduces detailedly the principle of NQR detection through nuclear quadrature, nuclear quadrupole energy level and NQR. Considering the wide application of NQR of 14N, the paper gives the system of the technology of 14N, NQR and the function of the parts. And the result of the detection is shown in the end
[en] Using a covariant spectator constituent quark model we predict an electric quadrupole moment -0.042 efm2 and a magnetic octupole moment -0.0035 efm3 for the Delta+ excited state of the nucleon.
[en] Studies of the machine imperfections in the RAON superconducting linac (SCL) that employs normal conducting (NC) quadrupoles were done to assess the tolerable error budgets of the machine imperfections that ensure operation of the beam. The studies show that the beam loss requirement is met even before the orbit correction and that the beam loss requirement is met even without the MHB (multi-harmonic buncher) and VE (velocity equalizer) thanks to the RAON’s radio-frequency quadrupole (RFQ) design feature. For the low energy section of the linac (SCL3), a comparison is made between the two superconducting linac lattice types: one lattice that employs NC quadrupoles and the other that employs SC solenoids. The studies show that both lattices meet the beam loss requirement after the orbit correction. However, before the orbit correction, the lattice employing SC solenoids does not meet the beam loss requirement and can cause a significant beam loss, while the lattice employing NC quadrupoles meets the requirement. For the lattice employing SC solenoids, care must be taken during the beam commissioning.
[en] The "5"3Cr resonance frequency in ammonium dichromate has been detected at 4202 kHz giving a Qcc of 8404 kHz (assuming η= 0). Calculations suggest that the value of the "5"3Cr quadrupole moment is about 84 mB lower that the currently accepted value. The resonance frequencies of two "1"7O nuclei have also been detected giving Qcc = 2800, 2890 kHz and η = 0.726, 0.780 respectively. The value for coupling and asymmetry parameter for "1"4N has been refined using zero field NQR giving a value Qcc = 78.8 kHz and η= 0.645 the asymmetry value being considerably lower than the value previous reported.
[en] Allowed transition energies and eigenstate expansions have been calculated and tabulated in numerical form as functions of the electric field gradient asymmetry parameter for the zero field Hamiltonian of quadrupolar nuclides with , and . These results are essential to interpret nuclear quadrupole resonance (NQR) spectra and extract accurate values of the electric field gradient tensors. Applications of NQR methods to studies of electronic structure in heavy element systems are proposed.