Total projectile electron loss cross sections ofU28+ions in collisions with gaseous targets ranging from hydrogen to krypton

G Weber,M S Sanjari,M O Herdrich,D F A Winters,R D Dubois,S Hagmann,Yu A Litvinov,R E Grisenti,Th Stöhlker,F Nolden,N Petridis,H Beyer,L Bozyk,T Gassner,P.-M Hillenbrand

doi:10.1103/physrevstab.18.034403

Abstract

Beam lifetimes of stored ${\mathrm{U}}^{28+}$ ions with kinetic energies of 30 and $50\text{ }\mathrm{MeV}/\mathrm{u}$, respectively, were measured in the experimental storage ring of the GSI accelerator facility. By using the internal gas target station of the experimental storage ring, it was possible to obtain total projectile electron loss cross sections for collisions with several gaseous targets ranging from hydrogen to krypton from the beam lifetime data. The resulting experimental cross sections are compared to predictions by two theoretical approaches, namely the CTMC method and a combination of the DEPOSIT code and the RICODE program.

Highlights

Charge-changing processes, i.e., loss or capture of electrons, occurring in ion-atom and ion-ion collisions belong to the most basic interactions in all types of plasmas and in accelerator facilities
The experimental data are compared to predictions based on a combination of a classical deposition model (DEPOSIT code) [33,34] and the relativistic ionization code (RICODE) developed by Shevelko et al [35] and, where available, to n-body classical trajectory Monte Carlo (CTMC) calculations by Olson [29]
At GSI, U28þ ions were pre-accelerated in the Universal Linear Accelerator (UNILAC) and subsequently injected into the heavy ion synchrotron SIS18 where the projectiles were further accelerated to beam energies of 30 and 50 MeV=u, respectively

Summary

INTRODUCTION

Charge-changing processes, i.e., loss or capture of electrons, occurring in ion-atom and ion-ion collisions belong to the most basic interactions in all types of plasmas and in accelerator facilities. Exact knowledge of the charge-changing cross sections is of crucial importance for the planning of ion-beam experiments in existing accelerators and storage rings as well as for the design of new facilities or upgrade programs. The existing heavy-ion synchrotron SIS18 of the GSI facility will serve as an injector for the new SIS100, which will be the main workhorse of the new facility providing U28þ beams with 5 × 1011 ions and energies up to 2.7 GeV=u [10] To meet this specifications, the SIS18 will have to deliver more than 1 × 1011 U28þ ions with an energy of 200 MeV=u and a repetition rate of 2.7 Hz. in 2007 dynamical vacuum effects as described above limited the maximum number of extracted particles for this ion species to 6.5 × 109 [11]. The experimental data are compared to predictions based on a combination of a classical deposition model (DEPOSIT code) [33,34] and the relativistic ionization code (RICODE) developed by Shevelko et al [35] and, where available, to n-body classical trajectory Monte Carlo (CTMC) calculations by Olson [29]

MEASUREMENT TECHNIQUE AND DATA ANALYSIS

RESULTS AND DISCUSSION

N2 Ar H2 H2 N2 H2 N2 Ar Kr H2 H2 N2 Ne Ar Kr

SUMMARY AND CONCLUSIONS