Xe^"*" ions with charge up to ^ =33 and energies 3.7^ keV are scattered under a grazing angle of incidence from a clean and flat Al(l 11) surface. Because of the image charge interaction the ions are accelerated on the incident path towards the surface plane which results in increased effective angles of incidence for the scattered projectiles. From the angular distributions for reflected neutralized projectiles we deduce the image charge interaction energies gained by the incident ions in front of the surface. Our data are in fair agreement with a q ^^^ dependence for the image energies as predicted from a simple classical overbarrier model. PACS numbers: 79.20.Nc, 34.70.+e, In recent years the study of the interactions of slow multiply charged ions with surfaces has developed into a very active field of research in particle solid interactions.Investigations of x rays and in particular electron emission have provided important data for elucidating the relevant interaction mechanisms. There is convincing evidence that the multielectron capture and loss processes in front of a metal surface result in the population of multiply and highly excited levels in the projectile and that most of the sparsely populated inner shells of those "hollow atoms" survive the approach to the surface [1-5]. As a consequence most of the high initial potential energy of the projectile is available close to the surface plane and is liberated there or in the bulk in close encounters with target atoms and conduction electrons.In all these studies the kinetic energy of the projectiles with respect to the approach to the surface is an important parameter, since this energy is related directly to the interaction times with the surface. Already at an early stage in the study of the scattering of multicharged ions from surfaces it was pointed out that the acceleration of ions due to their image charge interaction sets a lower bound with respect to the interaction energies and interaction times with the surface [6]. Experimental studies on electron emission phenomena at low effective projectile energies (eV domain) have revealed clear indications for such effects [7-9]. Recently we have demonstrated a method to measure directly those image interaction energies [10].Aside from the relevance of image interaction energies for a reliable knowledge of the effective interaction energies/times in scattering experiments, their magnitude also provides important information on the interaction mechanisms. Since the image charge interaction is strongly dependent on the charge state of the particle, image interaction energies reflect the dynamics of neutralization of the multicharged ions in front of the surface plane [6][7][8][9][10][11][12]. Based on the demonstration of the feasibility of our method with ions in low charge states [10], we present here first consequent studies of image charge interaction energies for incident ions ranging from low to relatively high charges.In our experiments we scatter Xe^"*" ions under a grazing angle of incidence ^in^=...

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RHIC EBIS will be used for producing multicharged ions from helium to uranium using primary ions from various external ion sources. The EBIS is followed by an RFQ and short linac, forming the new preinjector which will produce beams used for physics at RHIC and the NASA Space Radiation Laboratory, The design of RHIC EBIS is based on the BNL Test EBIS, which was a successful 10A electron current prototype. Improvements have been made in the RHIC EBIS design to increase the capacity of the ion trap, repetition frequency of operation, electron current, acceptance for injected ions, and improve vacuum conditions in the ionization region. RHIC EBIS has been assembled and installed in its final position. Commissioning is now underway to reach its project parameters. The results of this commissioning stage are presented.

As part of a new heavy ion preinjector that will supply beams for the Relativistic Heavy Ion Collider and the National Aeronautics and Space Administration Space Radiation Laboratory, construction of a new electron beam ion source (EBIS) is now being completed. This source, based on the successful prototype Brookhaven National Laboratory Test EBIS, is designed to produce milliampere level currents of all ion species, with q/m=(1/6)-(1/2). Among the major components of this source are a 5 T, 2-m-long, 204 mm diameter warm bore superconducting solenoid, an electron gun designed to operate at a nominal current of 10 A, and an electron collector designed to dissipate approximately 300 kW of peak power. Careful attention has been paid to the design of the vacuum system, since a pressure of 10(-10) Torr is required in the trap region. The source includes several differential pumping stages, the trap can be baked to 400 C, and there are non-evaporable getter strips in the trap region. Power supplies include a 15 A, 15 kV electron collector power supply, and fast switchable power supplies for most of the 16 electrodes used for varying the trap potential distribution for ion injection, confinement, and extraction. The EBIS source and all EBIS power supplies sit on an isolated platform, which is pulsed up to a maximum of 100 kV during ion extraction. The EBIS is now fully assembled, and operation will be beginning following final vacuum and power supply tests. Details of the EBIS components are presented.