| Paper | Title | Other Keywords | Page | ||
|---|---|---|---|---|---|
| TUBX03 | Coupling impedance of the J-PARC kicker magnets | kicker, impedance, extraction, synchrotron | 140 | ||
|
The single- and twin-wire measurements both for the longitudinal ( ZL ) and transverse impedances ( ZT ) will be discussed for the J-PARC kicker magnets: a lumped circuit kicker and several types of traveling wave kickers. The question if a position shifted single-wire can measure ZT is discussed. The measurement results are compared with the equivalent circuit analysis. The relation between the imaginary part of the impedance and causality will also be discussed.
|
|
|
||
| WEAY06 | Experimental Strategy for Realization of 3-D Beam Ordering with Use of Tapered Cooling at S-LSR | laser, ion, vacuum, proton | 231 | ||
|
At ICR, Kyoto University, an ion storage/cooler ring, S-LSR has been operated since the October, 2005. S-LSR has capability of dispersion free mode* throughout the whole circumference in order to avoid the shear heating** due to momentum dispersion of ion beam orbits. With such a mode, we need a special devise to develop necessary coupling between the longitudinal and transverse degrees of freedom for 3-dimensional laser cooling.*** A Wien Filter, in which the magnetic and electric fields overlap with strengths compensating each other for ions with a certain velocity, is to be utilized in the straight section where the usual laser cooling is applied. Due to the potential difference caused by the electric field in the Wien Filter, the difference in horizontal position of the circulating ion creates the difference of the equillibrium energy after laser cooling, which realizes "Tapered Cooling"****. In the present paper, a possible strategy of experimental approach at S-LSR toward 3-dimensional crystalline ion beams with use of the Wien Filter is to be presented.
|
* M. Ikegami et al., PR-STAB,7, 120101(2004). |
|
||
| WEAZ07 | Shock wave propagation near 7 TeV proton beam in LHC collimator materials | proton, target, radiation, electron | 241 | ||
|
A study is presented to estimate the influence of the impact of a 7 TeV proton beam on the physical-mechanical material properties, such as C for collimators, and Cu elsewhere. The high energy stored in each bunch can produce a shock wave near the impacting proton beam in these materials. The theoretical model for the investigations of shock wave propagation in the collimator materials takes into account ionization, electronic excitation, and energy transfer from excited electronic subsystem in the materials to the ionic subsystem. The change of other physical properties of the material is also considered. The deposited energy is calculated with FLUKA [1]. The numerical results of the microstructure change in the material are presented for different numbers of bunches. The method allows investigating changes of density and internal pressure, the distributions of atomic and sound velocities, and the temperature profiles in electronic and ionic subsystems of materials near the front of shock wave. These results are very relevant for the understanding the behavior of collimator materials used in LHC under 7 TeV proton beam.
|
[1] A. Fasso et al. The physics models of FLUKA: status and recent development, CHEP 2003, LA Jolla, California, 2003 |
|
||
| WEBY03 | Experimental studies of IBS in RHIC and comparison with theory | emittance, ion, simulation, lattice | 259 | ||
|
A high-energy electron cooling system is presently being developed to overcome emittance growth due to Intra-beam Scattering (IBS) for heavy ion operation in RHIC. A critical item for choosing appropriate parameters of the cooler is an accurate description of the IBS. The analytic models were verified vs dedicated IBS measurements. Analysis of the 2004 data with the Au ions showed very good agreement for the longitudinal growth rates but significant disagreement with exact IBS models for the transverse growth rates. Experimental measurements were improved for the 2005 run with the Cu ions. Here, we present comparison of the 2005 data with theoretical models.
|
|
|
||
| WEBY04 | Refined Models of Intrabeam Scattering | scattering, proton, emittance, damping | 265 | ||
|
We discuss two extensions of intrabeam-scattering theory. First, starting from the Bjorken-Mtingwa recipe, general formulae are derived for the three electro-magnetic intrabeam scattering growth rates, including non-ultrarelativistic terms and vertical dispersion, but maintaining a Gaussian beam approximation. A few applications demonstrate the importance of the vertical dispersion. Second, aside from electromagnetic interactions, hadrons may also undergo nuclear scattering off each other. We estimate the magnitude of this process, and argue that the loss rate due to “nuclear intrabeam scattering” could become significant in high-energy proton or ion storage rings, such as the LHC.
|
|
|
||
| THAW07 | Transverse electron-antiproton instability in the Recycler Ring | electron, ion, resonance, impedance | 334 | ||
|
Lifetime degradation of electron-cooled ions was observed at several electron coolers. In the Recycler, both the lifetime drop and emittance growth of the e-cooled pbars are seen. A possible reason for that can be a coherent interaction between the electron and antiproton beams. A theoretical model of this instability is presented, and a practical recommendation for its suppression is explained and discussed.
|
|
|