Observations of Beam Losses Due to Bound-Free Pair Production in a Heavy-Ion Collider
Abstract
We report the first observations of beam losses due to bound-free pair production at the interaction point of a heavy-ion collider. This process is expected to be a major luminosity limit for the CERN Large Hadron Collider when it operates with Pb82+208 ions because the localized energy deposition by the lost ions may quench superconducting magnet coils. Measurements were performed at the BNL Relativistic Heavy Ion Collider (RHIC) during operation with 100GeV/nucleon Cu29+63 ions. At RHIC, the rate, energy and magnetic field are low enough so that magnet quenching is not an issue. The hadronic showers produced when the single-electron ions struck the RHIC beam pipe were observed using an array of photodiodes. The measurement confirms the order of magnitude of the theoretical cross section previously calculated by others.
- Publication:
-
Physical Review Letters
- Pub Date:
- October 2007
- DOI:
- 10.1103/PhysRevLett.99.144801
- arXiv:
- arXiv:0706.2292
- Bibcode:
- 2007PhRvL..99n4801B
- Keywords:
-
- 29.20.Dh;
- 25.75.-q;
- Storage rings;
- Relativistic heavy-ion collisions;
- Physics - Accelerator Physics;
- Nuclear Experiment
- E-Print:
- 4 pages, 5 figures. Added journal ref. Corrected typos. Fixed fig 1. Minor improvements to fig. 1,3,4. Rephrased a small number of sentences (p1,3,4). Added numerical values of the aperture and the displacement for Au (p 2). Changed reference 5, added name in acknowledgments (p 4)