Fast beam-ion instability simulations in the TESLA electron damping ring and the FEL beam transfer line

The Fast Beam-Ion Instability is considered potentially harmful in electron storage rings and linear colliders with short bunch spacing and high bunch charge, as it is the case in the proposed electron damping ring and the FEL beam transfer line of the future linear collider TESLA. This instability arises from interaction between a stored bunch and an ion cloud previously created by all heading bunches during a single pass. To study this effect and to determine the required vacuum conditions, a simulation code has been developed. The results of these simulation studies are presented in this paper

Advanced manned space flight simulation and training: An investigation of simulation host computer system concepts

The findings of a preliminary investigation by Southwest Research Institute (SwRI) in simulation host computer concepts is presented. It is designed to aid NASA in evaluating simulation technologies for use in spaceflight training. The focus of the investigation is on the next generation of space simulation systems that will be utilized in training personnel for Space Station Freedom operations. SwRI concludes that NASA should pursue a distributed simulation host computer system architecture for the Space Station Training Facility (SSTF) rather than a centralized mainframe based arrangement. A distributed system offers many advantages and is seen by SwRI as the only architecture that will allow NASA to achieve established functional goals and operational objectives over the life of the Space Station Freedom program. Several distributed, parallel computing systems are available today that offer real-time capabilities for time critical, man-in-the-loop simulation. These systems are flexible in terms of connectivity and configurability, and are easily scaled to meet increasing demands for more computing power

Beam-beam effects in space charge dominated ion beams

During low-energy operations below the regular injection energy in the Relativistic Heavy Ion Collider (RHIC), significant beam lifetime reductions due to the beam-beam interaction in conjunction with large space charge tune shifts have been observed. We report on dedicated experiments aimed at understanding this phenomenon as well as preliminary simulation results, and propose alternative working points to improve the beam lifetime in future lowenergy RHIC runs.Comment: 6 pages, contribution to the ICFA Mini-Workshop on Beam-Beam Effects in Hadron Colliders, CERN, Geneva, Switzerland, 18-22 Mar 201

An Investigation on Cooling of CZT Co-Planar Grid Detectors

The effect of moderate cooling on CdZnTe semiconductor detectors has been studied for the COBRA experiment. Improvements in energy resolution and low energy threshold were observed and quantified as a function of temperature. Leakage currents are found to contribute typically $\sim$5 keV to the widths of photopeaks.Comment: 14 pages, 9 figures. Accepted for publication in Nuclear Inst. and Methods in Physics Research,

Multipole Error Data Analysis for RHIC Low-Energy Operations

N/

adron Beam Emittance Growth Due to Electron Beam Parameter Jitter in Linac-Ring Electron-Ion Colliders

N/

Transverse beam tail shaping in HERA-p by means of tune modulation

The HERA-B experiment utilizes an internal wire target in the halo of the stored proton beam in order to study CP violation. As operational experience shows, interaction rates tend to be extremely sensitive to tiny orbit jitter amplitudes. In order to stabilize these interaction rates, various methods have been studied to increase diffusion in the transverse proton beam tails without affecting the luminosity at the electron-proton collider experiments ZEUS and H1. Tune modulation was found to be a promising method for this task. The present status of these experiments willbe reported

Overcoming a fast transverse instability by means of octupole-induced tune spread in the Relativistic Heavy Ion Collider

During the Relativistic Heavy Ion Collider commissioning in 2001 a fast transverse instability was observed on the ramp. In general this could be counteracted with increased chromaticity, resulting in Landau damping. However this method could not be applied around transition energy where chromaticities have to change sign. So octupoles were used near transition energy to create transverse Landau damping and avoid the transverse instability, emittance blowup, and beam loss. This paper describes the considerations that led to the present scheme, as well as experimental results