Update on Ion Studies

Simulation study of fast ion instability in the ILC damping ring and PETRA III

The fast ion instability is simulated in different gas pressures and fill patterns for the damping ring of the International Linear Collider (ILC) and PETRA III respectively. Beam size variation due to beta function and dispersion function change is taken into account. Feedback is also applied in the simulation.

Polarized positrons for the ILC - update on simulations

To achieve the extremely high luminosity for colliding electron-positron beams at the future International Linear Collider (ILC) an undulator-based source with about 230 meters helical undulator and a thin titanium-alloy target rim rotated with tangential velocity of about 100 meters per second are foreseen. The very high density of heat deposited in the target has to be analyzed carefully. The energy deposited by the photon beam in the target has been calculated in FLUKA. The resulting stress in the target material after one bunch train has been simulated in ANSYS.

The impact of fill patterns on the fast ion instability in the ILC damping ring

The ions produced via collisional ionization of the residual gas molecules in vacuum pipe with the circulating electron beam have deleterious effect on the beam properties and may become a limiting factor for the machine's performance. For the electron damping ring of the International Linear Collider (ILC), the ion instability is noticeable due to the ultra-low beam emittance with many bunches operation. In this paper, the different beam fill patterns are investigated and their effects on the fast ion instability are discussed. The simulations show that the mini train fill patterns can reduce…

Radiation damage of the ILC positron source target

The radiation damage of the positron source target for the International Linear Collider (ILC) has been studied. The displacement damage in target material due to multi-MeV photons has been calculated by combining FLUKA simulations for secondary particle production, SPECTER data for neutron displacement cross-sections and the Lindhard model for estimations of displacement damage by ions. The radiation damage of a stationary Ti6Al4V target in units of displacements per atom (dpa) has been estimated for photons from an undulator with strength 0.92 and period 1.15 cm. The calculated damage is 7 d…

CESR Test Accelerator

The Cornell Electron Storage Ring (CESR) was reconfigured in 2008 as a test accelerator to investigate the physics of ultra-low emittance damping rings. During the approximately 40 days/year available for dedicated operation as a test accelerator, specialized instrumentation is used to measure growth and mitigation of the electron cloud, emittance growth due to electron cloud, intra-beam scattering, and ions, and single and multi-bunch instabilities generated by collective effects. The flexibility of the CESR guide field optics and the integration of accelerator modeling codes with the control…

蜘蛛离子源与引出电源——运行四年后的设计更新

Spider Ion Source and Extraction Power Supplies -- An update of the design after four years of operation

本文基于SPIDER离子源四年运行经验，重新评估ISEPS中偏置电源的设计要求，提出将其从单象限谐振变换器改为四象限运行并将额定输出电压提高一倍。