Photoelectron-photofragment coincidence spectroscopy in a cryogenically cooled linear electrostatic ion beam trap

Journal Article · Sat Oct 15 00:00:00 EDT 2011 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.3641875· OSTI ID:22063736

Johnson, Christopher J ^[1]; Shen, Ben B; Poad, Berwyck L. J.; Continetti, Robert E ^[2]

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1. Department of Physics, University of California, San Diego, La Jolla, California 92093-0340 (United States)
2. Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0340 (United States)

A cryogenically cooled linear electrostatic ion beam trap for use in photoelectron-photofragment coincidence (PPC) spectroscopy is described. Using this instrument, anions created in cold, low-duty-cycle sources can be stored for many seconds in a {approx}20 K environment to cool radiatively, removing energetic uncertainties due to vibrationally excited precursor anions. This apparatus maintains a well-collimated beam necessary for high-resolution fragment imaging and the high experimental duty cycle needed for coincidence experiments. Ion oscillation is bunched and phase-locked to a modelocked laser, ensuring temporal overlap between ion bunches and laser pulses and that ions are intersected by the laser only when travelling in one direction. An electron detector is housed in the field-free center of the trap, allowing PPC experiments to be carried out on ions while they are stored and permitting efficient detection of 3-dimensional electron and neutral recoil trajectories. The effects of trapping parameters on the center-of-mass trajectories in the laser-ion interaction region are explored to optimize neutral particle resolution, and the impact of bunching on ion oscillation is established. Finally, an initial demonstration of radiative cooling is presented.

• OSTI ID: 22063736
• Journal Information: Review of Scientific Instruments, Vol. 82, Issue 10; Other Information: (c) 2011 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
ANIONS
BEAM BUNCHING
BEAM COOLING
CENTER-OF-MASS SYSTEM
COINCIDENCE METHODS
ELECTRON DETECTION
ION BEAMS
LASERS
MODE LOCKING
NEUTRAL PARTICLES
OSCILLATIONS
PARTICLE DISCRIMINATION
PHOTOELECTRON SPECTROSCOPY
PULSES
RADIATIVE COOLING
RECOILS
TRAJECTORIES
TRAPS