0000000000179593
AUTHOR
Ulrich Schramm
showing 7 related works from this author
Characterization and Tuning of Ultra High Gradient Permanent Magnet Quadrupoles
2009
The application of quadrupole devices with high field gradients and small apertures requires precise control over higher order multipole field components. We present a new scheme for performance control and tuning, which allows the illumination of most of the quadrupole device aperture because of the reduction of higher order field components. Consequently, the size of the aperture can be minimized to match the beam size achieving field gradients of up to $500\text{ }\text{ }\mathrm{T}\text{ }{\mathrm{m}}^{\ensuremath{-}1}$ at good imaging quality. The characterization method based on a Hall probe measurement and a Fourier analysis was confirmed using the high quality electron beam at the M…
Concept of a high-resolution online mass separator for the Munich fission fragment accelerator
1997
A fission fragment accelerator combined with the Munich high-flux reactor FRM-II is under design for the delivery of intense beams of mass separated very neutron-rich fission fragments with energies at the Coulomb barrier They can be used to produce very heavy neutron-rich nuclei in fusion reactions. The large neutron excess will result in much longer lifetimes of the produced heavy elements, compared to neutron-deficient ones produced in reactions with stable nuclear beams. Thus fast a-chains can no longer be used to identify the heavy reaction products. A new separator will be used consisting of a velocity filter, an ion guide system (IGISOL) and a Penning trap. The velocity filter separa…
The dynamics of bunched laser-cooled ion beams at relativistic energies
2007
We discuss the axial dynamics of laser-cooled relativistic C3+ ion beams at moderate bunching voltages. Schottky noise spectra measured at a beam energy of 122 MeV/u are compared to simulations of the axial beam dynamics. Ions confined in the bucket are addressed by the narrow-band force of a laser beam counter-propagating to the ion beam, while the laser frequency is detuned relatively to the cooling transition frequency in the rest frame of the bucket. At large detuning comparable to the momentum acceptance of the bucket, the axial dynamics can be well explained by the secular motion of individual non-interacting ions. At small detuning, corresponding to a small axial momentum spread Δpax…
Transverse laser cooling of a radio-frequency bunched ion beam in the storage ring TSR
1996
Abstract We report on the observation of the indirect transverse laser cooling effect in a radio-frequency bunched beam of 7.3 MeV 9 Be + ions, stored in the Heidelberg Test Storage Ring and subject to direct longitudinal laser cooling. This bunched scheme offers particular advantages for producing ultracold beams with unprecedented phase-space densities.
Miniature magnetic devices for laser-based, table-top free-electron lasers
2007
Truly table-top sized radiation sources based on compact laser-plasma accelerators require compact and strong focusing devices and efficient short-period undulators. Complementing our recent theoretical work on the feasibility of a table-top FEL, we here present the design and successful experimental characterizations of a 5 mm period length undulator and miniature quadrupole magnets with field gradients of the order of $500\text{ }\text{ }\mathrm{T}/\mathrm{m}$.
Laser cooling of stored relativistic ion beams with large momentum spreads using a laser system with a wide scanning range
2014
New results on laser cooling of stored, bunched, relativistic ion beams are presented. For the first time it has been possible to cool an ion beam with large momentum spread without initial electron cooling or scanning of the bunching frequency by using a single cw laser system.
Laser cooling of relativistic heavy-ion beams for FAIR
2015
Laser cooling is a powerful technique to reduce the longitudinal momentum spread of stored relativistic ion beams. Based on successful experiments at the experimental storage ring at GSI in Darmstadt, of which we show some important results in this paper, we present our plans for laser cooling of relativistic ion beams in the future heavy-ion synchrotron SIS100 at the Facility for Antiproton and Ion Research in Darmstadt.