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Title |
Page |
| WEBY01 |
Commisioning of Electron Beam Cooling at S-LSR
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247 |
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- T. Shirai, S. Fujimoto, M. Ikegami, A. Noda, H. Souda, M. Tanabe, H. Tongu
Kyoto ICR, Uji, Kyoto
- H. Fadil, M. Grieser
MPI-K, Heidelberg
- T. Fujimoto, S. I. Iwata, S. Shibuya
AEC, Chiba
- I. N. Meshkov, I. A. Seleznev, A. V. Smirnov, E. Syresin
JINR, Dubna, Moscow Region
- K. Noda
NIRS, Chiba-shi
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S-LSR is a new compact ion cooler ring at Kyoto University. The circumference is 22.557 m. The commissioning of the electron cooling was started using the 7 MeV proton beam from November, 2005. The total length of the electron cooler is 1.63 m. In order to maximize the effective cooling length in the limited space, the magnetic field of the solenoid and the troid coils was calculated precisely by the 3D code. The electrostatic deflector for the electron and the steering magnet for the ion are placed in the troid. The performances of these devices are evaluated by the cooling measurements. Experiments using the electron cooling are also stared. One is an induction sweep cooling of the proton beam. It is an cooling with the assist of the induction acceleration and possible to reduce the cooling time of the hot ion beams like secondary particles. We also observe the behavior of the cooled ion beam in the small ion number case and the large ion number case. We discuss about the possibility of the phase transition of the proton in the former case and discuss about the coherent instability conditions in the latter case.
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| WEBY03 |
Experimental studies of IBS in RHIC and comparison with theory
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259 |
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- A. V. Fedotov, W. Fischer, S. Tepikian, J. Wei
BNL, Upton, Long Island, New York
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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.
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| WEBY04 |
Refined Models of Intrabeam Scattering
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265 |
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- F. Zimmermann, F. Ruggiero
CERN, Geneva
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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.
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| WEBY05 |
Simulating dynamical friction in wiggler-based high-energy electron coolers, including finite-time effects
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0 |
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- G. I. Bell, D. T. Abell, D. L. Bruhwiler, R. Busby, P. Messmer
Tech-X, Boulder, Colorado
- I. Ben-Zvi, A. V. Fedotov, V. Litvinenko
BNL, Upton, Long Island, New York
- A. O. Sidorin
JINR, Dubna, Moscow Region
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The proposed RHIC-II luminosity upgrade includes a novel electron cooling section, using ~55 MeV electrons to cool fully-ionized gold. We present simulations of the dynamical friction force exerted on the Au ions. Rather than a strong solenoid, a long helical wiggler magnet is used to provide focusing and suppress recombination. In the rest frame of the relativistic electron and ion beams, with non-relativistic motion and electrostatic fields, the Lorentz transformed wiggler field yields strong, rapidly-varying electric fields. The VORPAL simulation framework applies a semi-analytic binary collision algorithm, in which ion-electron collisions are modeled pairwise. This model is combined with standard particle-in-cell (PIC) techniques, through an operator-splitting approach, to include the effects of external fields. Charge shielding due to electron-electron interactions is also included via PIC. Simulated friction results are compared with BETACOOL, which integrates the standard unmagnetized formulas. With finite interaction times and electron wiggle motion correctly included, we find good agreement with VORPAL.
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