Accession Number DE2012-1020957
Title CESR Conversion Damping Ring Studies of Electron Cloud Instabilities (CESR-TA).
Publication Date Aug 2011
Media Count 47p
Personal Author D. L. Rubin M. A. Palmer
Abstract In the International Linear Collider, two linear accelerators will accelerate bunches of positrons and electrons to over a hundred billion electron volts and collide them in a central detector. In order to obtain useful collision rates, the bunches, each containing twenty billion particles, must be compressed to a cross section of a few nanometers by a few hundred nanometers. In order to prepare these ultra high density bunches, damping rings (DRs) are employed before the linear accelerators. The DRs take the high emittance bunches that are provided by the electron and positron sources and, through the process of radiation damping, squeeze them into ultra low emittance beams that are ready for the main linear accelerators. In the damping rings, a number of effects can prevent the successful preparation of the beams. In the electron ring, an effect known as the fast ion instability can lead to beam growth and, in the positron ring, the build-up of an electron cloud (EC), which interacts with the circulating bunches, can produce the same effect. EC build-up and the subsequent interaction of the cloud with the positron beam in the DR have been identified as major risks for the successful construction of a linear collider. The CESRTA research program at the Cornell Electron Storage Ring (CESR) was developed in order to study the build-up of the EC, the details of its impact on ultra low emittance beams, as well as methods to mitigate the impact of the cloud. In the DR, the EC forms when synchrotron photons radiated from the circulating beam strike the walls of the vacuum chamber, resulting in the emission of photoelectrons.
Keywords Accelerators
Beam emittance
Cross sections
Damping
Electron cloud
Electrons
Instability
Linear colliders
Positrons
Storage rings


 
Source Agency Technical Information Center Oak Ridge Tennessee
NTIS Subject Category 46 - Physics
Corporate Author Cornell Univ., Ithaca, NY.
Document Type Technical report
Title Note N/A
NTIS Issue Number 1226
Contract Number DE-FC02-08ER41538

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