Paper 
Title 
Page 
WEBY01 
Commisioning of Electron Beam Cooling at SLSR

247 

 T. Shirai, S. Fujimoto, M. Ikegami, A. Noda, H. Souda, M. Tanabe, H. Tongu
Kyoto ICR, Uji, Kyoto
 H. Fadil, M. Grieser
MPIK, 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, Chibashi



SLSR 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.


WEBY03 
Experimental studies of IBS in RHIC and comparison with theory

259 

 A. V. Fedotov, W. Fischer, S. Tepikian, J. Wei
BNL, Upton, Long Island, New York



A highenergy electron cooling system is presently being developed to overcome emittance growth due to Intrabeam 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

265 

 F. Zimmermann, F. Ruggiero
CERN, Geneva



We discuss two extensions of intrabeamscattering theory. First, starting from the BjorkenMtingwa recipe, general formulae are derived for the three electromagnetic intrabeam scattering growth rates, including nonultrarelativistic 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 highenergy proton or ion storage rings, such as the LHC.


WEBY05 
Simulating dynamical friction in wigglerbased highenergy electron coolers, including finitetime effects

0 

 G. I. Bell, D. T. Abell, D. L. Bruhwiler, R. Busby, P. Messmer
TechX, Boulder, Colorado
 I. BenZvi, A. V. Fedotov, V. Litvinenko
BNL, Upton, Long Island, New York
 A. O. Sidorin
JINR, Dubna, Moscow Region



The proposed RHICII luminosity upgrade includes a novel electron cooling section, using ~55 MeV electrons to cool fullyionized 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 nonrelativistic motion and electrostatic fields, the Lorentz transformed wiggler field yields strong, rapidlyvarying electric fields. The VORPAL simulation framework applies a semianalytic binary collision algorithm, in which ionelectron collisions are modeled pairwise. This model is combined with standard particleincell (PIC) techniques, through an operatorsplitting approach, to include the effects of external fields. Charge shielding due to electronelectron 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.

