Cornell University, Department of Physics, Ithaca, New York
CLASSE, Ithaca
University of Minnesota, Minneapolis, Minnesota
CESR-LEPP, Ithaca, New York
Technion, Haifa
In April 2008, we propose to begin operation of the Cornell Electron Storage Ring (CESR) as a test accelerator, CesrTA, for International Linear Collider (ILC) damping ring research. Utilizing 12 damping wigglers, the baseline CesrTA lattice at 2.0 GeV will offer a natural geometric emittance of 2.25 nm. An experimental program has been laid out which focuses on several key areas of damping rings R&D. First we will test vacuum chamber designs to suppress electron cloud growth in the wiggler magnets. Secondly, we will develop correction, tuning and emittance monitoring strategies to achieve vertical emittances of a few picometers. As part of this effort we will validate alignment and survey techniques being developed by the Linear Collider Alignment and Survey group (LiCAS) for curved tunnel applications. After achieving ultra-low emittance, we intend to explore the impact of the electron cloud, the fast ion instability and other beam dynamics effects on ultra-low emittance beams. Finally, we plan to test various technical systems required for the ILC damping rings. This paper provides an update on conceptual design issues for CesrTA and describes the experimental program in detail.
Technion, Haifa
Franck and Hertz in 1914 were the first to demonstrate that free electrons can be decelerated by mercury atoms in discrete energy quanta. In 1930 Latyscheff and Leipunsky have demonstrated the inverse effect namely; free electrons can be accelerated by energy stored in the mercury atoms (collision of the second kind). It was only in 1958 that Townes has used multiple collisions between photons and excited atoms to amplify radiation (MASER & LASER). In 1995 Schachter suggested to use excited atoms for coherently accelerate particles. The results of a proof-of-principle experiment (2006) demonstrating the PASER scheme are reported here. Performed at the BNL-ATF, the essence of the experiment is to inject a 45MeV density modulated beam into an excited CO2 gas mixture. Resonance is insured by having the beam bunched by its interaction with a high-power CO2 laser pulse within a wiggler. The electrons experienced 0.15% relative change in their kinetic energy, in less than 40cm long interaction region. The experimental results indicate that a fraction of these electrons have gained 200keV each, implying that such an electron has undergone 2,000,000 collisions of the second kind.
Euclid TechLabs, LLC, Solon, Ohio
ANL, Argonne, Illinois
International Tomography Center, SB RAS, Novosibirsk
Saint-Petersburg State University, Saint-Petersburg
Technion, Haifa
The PASER is a new method for particle acceleration, in which energy from an active medium is transferred to a charged particle beam. The effect is similar to the action of a maser or laser with the stimulated emission of radiation being produced by the virtual photons in the electromagnetic field of the beam. We are developing a demonstration PASER device operating at X-band, based on the availability of a new class of active materials that exhibit photoinduced electron spin polarization. We will report on the status of active material development and measurements, numerical simulations, and preparations for microwave PASER experiments at the Argonne Wakefield Accelerator facility.