Observation of magnetic resonances in electron clouds in a positron storage ring
نویسنده
چکیده
The first experimental observation of magnetic resonances in electron clouds is reported. The resonance was observed as a modulation in cloud intensity for uncoated as well as TiN-coated aluminum surfaces in the positron storage ring of the PEP-II collider at SLAC. Electron clouds frequently arise in accelerators of positively charged particles, and severely impact the machines’ performance. The TiN coating was found to be an effective remedy, reducing the cloud intensity by three orders of magnitude. & 2010 Elsevier B.V. All rights reserved.
منابع مشابه
Effects of Structure and Partially Localization of the π Electron Clouds of Single-Walled Carbon Nanotubes on the Cation-π Interactions
A C102H30 graphene sheet has been rolled up to construct Single-Walled Carbon NanoTube Fragments (SWCNTFs) as parts of armchair carbon nanotubes by computational quantum chemistry methods. Non-covalent cation-π interactions of the Na+ cation on the central rings of SWCNTFs have investigated. The binding energies of the Na+-SWCNTF complexes versus ...
متن کاملBadron States of Even Charge Conjugation from Electron-positron Annmilation*
We show how electron-positron storage rings may be used to obtain information on hadronic states with even charge conjugation. This is illustrated by studying the reaction ee+xn+r, the analysis of which should reveal information on even-C dipion resonances, such as the existence of the E -meson. (Submitted to Physical Review Letters)
متن کاملHead-tail instability caused by electron clouds in positron storage rings
In positron or proton storage rings with many closely spaced bunches, an electron cloud can build up in the vacuum chamber due to photoemission or secondary emission. We discuss the possibility of a single-bunch two-stream instability driven by this electron cloud. Depending on the strength of the beam-electron interaction, the chromaticity and the synchrotron oscillation frequency, this instab...
متن کاملDiagnostics for Electron Cloud Measurements in CESR
Clouds of low energy electrons frequently build up within the beam chambers of particle accelerators. In many cases, electron cloud effects (ECEs) cause beam instabilities and degradation of performance. This is of particular concern for high intensity positron rings, in which ECEs can lead to emittance blow-up. Understanding and mitigating electron cloud build up is thus of particular importan...
متن کاملPET Radiopharmaceuticals
PET (positron emission tomography) is a powerful imaging technique that can provide quantitative information on the distribution of positron emitter labeled radiopharmaceuticals (PET radiopharmaceuticals) in the body. Positrons (ß+) are positively charged beta particles. They are emitted when the atom is proton rich. A positron has only a transient existence. After losing all of its kinetic ene...
متن کامل