NSCL, East Lansing, Michigan, USA
FRIB, East Lansing, USA
Northern Illinois University, DeKalb, Illinois, USA
The Reaccelerator (ReA) Facility at the National Superconducting Cyclotron Laboratory (NSCL) located at Michigan State University (MSU) offers the low-energy nuclear science community unique capabilities to explore wider ranges of nuclear reactions and the structure of exotic nuclei. Future sensitive time-of-flight experiments on ReA will require the widening of pulse separation for improved temporal resolution in single bunch detection while minimizing loss of rare isotopes and cleaning of beam decay products that might pollute measurements. In this proceedings, we present a preliminary design of a heavy ion ring that will address the task of bunch compression, bunch separation enhancement, satellite bunches elimination, cleaning of decay products, beam loss mitigation, and improvement of beam transmission.
BNL, Upton, Long Island, New York, USA
To combat triplets vibration, the global orbit feedback system with frequency about 10 Hz was developed and en- gaged in operation at injection and top energy in 2010, dur- ing beam acceleration in 2012 at RHIC. The system has performed well with keeping 6 out of 12 eigenvalues for the orbit response matrix. However, we observed correc- tor current transients with the lattice for polarized proton program in 2015 which resulted in corrector power supply trips. In this report, we will present the observation, an- alyze the cause and also optimize the feedback algorithm to overcome the newly emerged problem with the feedback system.
MIT/PSFC, Cambridge, Massachusetts, USA
Three novel ideas for wakefield acceleration (WFA) of electrons with metallic periodic subwavelength structures will be presented. The first idea is a deep corrugation structure for collinear WFA. A design for the Argonne Wakefield Accelerator is shown. An analytical model is developed and it agrees with the CST wakefield solver. A scaling study has been performed, and ways to increase the gradient will be discussed. The deep corrugation structure can generate a higher gradient than a dielectric tube with the same beam aperture when excited by the same bunch. The second idea is an elliptical structure for two-beam acceleration (TBA). The unit cell is an elliptical cavity, and the drive beam hole and the witness beam hole are located around the two focal points. The TBA process has been calculated and will be presented. The third idea is a metamaterial ‘wagon wheel' structure for a power extractor design. The fundamental mode is a TM mode with a negative group velocity. A power extractor at 11.7 GHz based on the structure can reach a GW power level when a train of 40 nC bunches with 1.3 GHz rep rate are sent in.
Northern Illinois University, DeKalb, Illinois, USA
A plasmon-assisted channeling acceleration can be realized with a large channel possibly in a nanometer scale. Carbon nanotubes are the most typical example of nano-channels that can confine a large amount of channeled particles and confined plasmon in a coupling condition. This paper presents theoretical and numerical study on the concept of the laser-driven surface-plasmon (SP) acceleration in a carbon nanotube (CNT) channel. Analytic description of the SP-assisted laser acceleration is detailed with practical acceleration parameters, in particular with specifications of a typical tabletop femto-second laser system. The maximally achievable acceleration gradients and energy gains within dephasing lengths and CNT lengths are discussed with respect to laser-incident angles and CNT-filling ratios.
BNL, Upton, Long Island, New York, USA
25 years ago, Brookhaven Accelerator Test Facility (ATF), sponsored by the U.S. Department of Energy's (DOE's) Office of High-Energy Physics (HEP), pioneered a concept of a proposal-driven user facility for advanced accelerator research using lasers and electron beams. Since then, the ATF became an internationally recognized destination for researchers to benefit from free access to unique equipment not affordable otherwise to individual institutions and businesses. We will show by examples how collaborative user research achieves high productivity when supported by the ATF's capabilities. Researchers from academia, industry and national laboratories coming to ATF successfully investigate wide range of topics. Recently endorsed as an Office of Science National User Facility and a flagship in Accelerator Stewardship, ATF continues broadening its user community. DOE is now planning a considerable expansion of the ATF's capabilities via simultaneously upgrading the parameters of the e-beam and laser.