Atomic collisions with 33-TeV lead ions

Journal Article · Wed May 01 04:00:00 EDT 1996 · Bulletin of the American Physical Society

OSTI ID:394236

Vane, C R ^[1]

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1. Oak Ridge National Lab., TN (United States)

In Coulomb collisions at sufficiently high energies, highly charged ions can readily excite or ionize electrons from the negative energy continuum into observable atomic bound states of the ion or into states of the positive continuum. The latter process appears as production of a free electron-positron pair. The former process appears at atomic electron capture, with the ion changing charge by one unit, and simultaneous emission of a free positron. The cross sections grow with collision energy. At ultrarelativistic energies, the capture from pair production mechanism dominates all others for all targets. Cross sections are much larger for ionization of these {open_quote}captured{close_quote} pair electrons in subsequent collisions in solid targets, so that competition of capture and loss leads to very small ({le}10{sup {minus}3}) one-electron equilibrium charge-state fractions. For relativistic heavy-ion colliders, however, the charge-changed ion will survive the interaction region and be lost from storage at the first magnetic bend. The capture cross section will determine the upper limits for operational storage time-luminosity products achievable at future colliders. Using 33-TeV lead ions from the CERN SPS accelerator, the authors have measured atomic one-electron capture and loss for targets of C, Al, Cu, and Au. Methods and results of these measurements will be presented and compared with current theoretical calculations.

• DOE Contract Number: AC05-96OR22464
• OSTI ID: 394236
• Report Number(s): CONF-9605105--
• Journal Information: Bulletin of the American Physical Society, Journal Name: Bulletin of the American Physical Society Journal Issue: 3 Vol. 41; ISSN BAPSA6; ISSN 0003-0503
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
ALUMINIUM
CARBON
COPPER
CROSS SECTIONS
ELECTRON CAPTURE
GOLD
ION COLLISIONS
LEAD IONS
TARGETS
TEV RANGE 10-100