Theory and application of plane elliptic multipoles for static magnetic fields

Phys. Rev. ST Accel. Beams

et al. 2009

Trapping by resonances or scattering off resonances induced by space charge (SC) or electron cloud (EC) in conjunction with synchrotron motion can explain observations of slow beam loss and emittance growth, which are often accompanied by changes in the longitudinal beam profile. In this paper we review the recent progress in understanding and modeling of the underlying mechanisms, highlight the differences and similarities between space charge and electron cloud, and discuss simulation results in the light of experimental observations, e.g., at GSI, CERN, and BNL. In particular, we address the role of the pinched electrons and describe in detail the complexity of the electron pinch formation. We present simulation results within a dipole or in a field-free region of the beam pipe, which reveal the morphology and main features of this phenomenon, explain the physical origin of the complex electron structures like stripe in either field configuration, and discuss the dependence on some key parameters.

Section: A Application To Sc Incoherent Effects Of Ion Beams In Sis100mentioning

confidence: 99%

Incoherent effect of space charge and electron cloud

Franchetti

Hofmann

Phys. Rev. ST Accel. Beams

et al. 2009

“…• measurement of the field quality of the virgin magnet using a rotating coil probe [24], [25]; • measurement of the local field with a hall probe (B y , vertical field); • determination of the integral field strength with a single stretched wire system; • measurement of the field quality with a rotating coil probe at various positions [24], [26]; • cross-check of the measured field quality by mapping the horizontal field B x using a hall probe with a compensation for the planar hall effect [27].…”

Section: B Magnetic Fieldmentioning

confidence: 99%

“…Therefore a consistent field description within the elliptic beam aperture is required. Elliptic multipoles and their transfer to circular multipoles allow for an appropriate and reliable description [26].…”

Section: ) Main Fieldmentioning

confidence: 99%

See 1 more Smart Citation

Fast-Ramped Superconducting Magnets for FAIR Production Status and First Test Results

IEEE Trans. Appl. Supercond.

Schnizer

Sugita

et al. 2015

The SIS100 synchrotron for heavy ion research is based on fast-ramped superconducting magnets. These superferric magnets are being designed, built, and tested. The first 3-m-long series dipole (maximum field of 1.9 T; ramp rate of 4 T/s) has been built. We present the test results obtained (quench training, magnetic field, ac loss, and repetition rate) and compare them with the predicted values and the required operation parameters.

“…The expansion coefficients ce 2n−1 in the second line may be determined from the field given in the first line by their definition as given in [21]. They may be converted into circular expansion coefficients by formulae given in the same reference.…”

Section: Eddy Currents: Elliptic Vacuum Tubementioning

confidence: 99%

Impact of the beam pipe design on the operation parameters of the superconducting magnets for the SIS 100 synchrotron of the FAIR project

Schnizer

Heil

et al. 2010

J. Phys.: Conf. Ser.

Impact of the beam pipe design on the operation parameters of the superconducting magnets for the SIS 100 synchrotron of the FAIR project Abstract. The SIS 100 accelerator of the Facility for Antiprotons and Ion Research (FAIR)at GSI Darmstadt will be the world's second fast ramped synchrotron utilising superconducting magnets in heavy ion research facilities. The request for high current Uranium beams requires vacuum of extremely high quality that can be achieved in long term operation only by cold vacuum chambers acting as a cryogenic pump. Its mechanical stable design options are strongly limited by AC loss generation and field distortion problems. Previous R&D indicated that cooling tubes, keeping the vacuum chamber below 15 K, create large additional eddy currents and thus deteriorate the field with a sextupole. This effect is most dominant at the start of the ramp. The ramp rate of the correctors is limited by the maximum available voltage and as by the heat created on the ramp up and the cooling efficiency of the Nuclotron-type cable. Thus we investigate different means to simplify the vacuum chamber design keeping its temperature below 15 K in the area where the highest suction pumping is required with alternative cooling methods as well as on the compensation margin the sextupole correctors can provide. This work was partly supported by the BMBF.