Electron Cloud Diagnostic for Quadrupole Magnets

75153S Electron cloud effects, including electron cloud induced instabilities, are a critical technical risk for the next generation of high intensity, accelerator-based research facilities. In particular, new diagnostics are required to observe electron cloud formation and trapping in quadrupole magnets, in order to test theories and simulations of cloud buildup and beam dynamics effects induced by electron clouds. To date, no diagnostics have been developed that can measure the electrons trapped in accelerator quadrupole magnets. This project will develop a diagnostic instrument that can measure electron cloud formation and trapping in quadrupole magnets used in high intensity rings or beam transport. In Phase I, extensive simulations of electron cloud formation and trapping in were made to determine the expected characteristics (including trapping) of the electron cloud in quadrupole magnets. The simulations revealed the unexpected result that numerous electrons were ejected from the quadrupole when the long bunch beam pulse was present. Based on these simulations, an optimized physics design for a diagnostic was developed. Phase II will involve the design, fabrication, and installation of a prototype diagnostic assembly. Tests of the prototype will evaluate the effectiveness of the diagnostic, and data on the electron cloud formation and trapping in quadrupoles will be collected. Commercial Applications and Other Benefits as described by the awardee: The results of this project should benefit the high intensity proton and positron rings now being upgraded, under construction, or under active consideration at such facilities as the Spallation Neutron Source, the International Linear Collider, the Relativistic Heavy Ion Collider, Proton Drivers for Neutrino Factories, the Japanese Proton Accelerator Complex, and the Large Hadron Collider. The primary commercial application would involve the adaptation of the diagnostic to accelerator rings or beam transport.