Localized beampipe heating due to e(-) capture and nuclear excitation in heavy ion colliders

At heavy ion colliders, two major sources of beam loss are expected to be e (+)e(-) production, where the e(-) is bound to one of the nuclei, and photo nuclear excitation and decay via neutron emission. Both processes alter the ions charged to mass ratio by well-defined amounts, creating beams of part icles with altered magnetic rigidity. These beams will deposit their energy in a localized region of the accelerator, causing localized heating. The s ize of the target region depends on the collider optics. For medium and hea vy ions, at design luminosity at the Large Hadron Collider, local heating m ay be more than an order of magnitude higher than expected. This could caus e magnet quenches if the local cooling is inadequate. The altered-rigidity beams will also produce localized radiation damage. The beams could also be extracted and used for fixed target experiments. (C) 2001 Elsevier Science B.V. All rights reserved.