A new double imaging velocity focusing coincidence experiment: i{sup 2}PEPICO

Journal Article · Wed Aug 15 04:00:00 EDT 2012 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.4742769· OSTI ID:22093693

Bodi, Andras; Hemberger, Patrick; Gerber, Thomas ^[1]; Sztaray, Balint ^[2]

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1. Paul Scherrer Institut, Villigen 5232 (Switzerland)
2. Department of Chemistry, University of the Pacific, Stockton, California 95211 (United States)

The vacuum ultraviolet (VUV) beamline of the Swiss Light Source has been upgraded after two years of operation. A new, turntable-type monochromator was constructed at the Paul Scherrer Institut, which allows for fast yaw-alignment as well as quick grating change and exchange. In addition to the original imaging photoelectron photoion coincidence endstation (iPEPICO), a second, complementary double imaging setup (i{sup 2}PEPICO) has been built. Volatile samples can be introduced at room temperature or in a molecular beam, a pyrolysis source allows for radical production, and non-volatile solids can be evaporated in a heated cell. Monochromatic VUV radiation ionizes the sample and both photoelectrons and photoions are velocity map imaged onto two fast position sensitive detectors and detected in delayed coincidence. High intensity synchrotron radiation leads to ionization rates above 10{sup 5} s{sup -1}. New data acquisition and processing approaches are discussed for recording coincidence processes at high rates. The setup is capable of resolving pulsed molecular beam profiles and the synchrotron time structure temporally. The latter is shown by photoelectron autocorrelation, which displays both the 1.04 MHz ring clock frequency as well as resolving the micro-pulses with a separation of 2 ns. Kinetic energy release analysis on the dissociative photoionization of CF{sub 4} indicates a dissociation mechanism change in the Franck-Condon allowed energy range of the first ion state.

• OSTI ID: 22093693
• Journal Information: Review of Scientific Instruments, Journal Name: Review of Scientific Instruments Journal Issue: 8 Vol. 83; ISSN 0034-6748; ISSN RSINAK
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
ALIGNMENT
CARBON TETRAFLUORIDE
DATA ACQUISITION
ENERGY RANGE
FAR ULTRAVIOLET RADIATION
GRATINGS
MASS SPECTROSCOPY
MOLECULAR BEAMS
MONOCHROMATIC RADIATION
MONOCHROMATORS
PHOTOELECTRON SPECTROSCOPY
PHOTOIONIZATION
POSITION SENSITIVE DETECTORS
PYROLYSIS
RINGS
SOLIDS
SWISS LIGHT SOURCE
SYNCHROTRON RADIATION
TEMPERATURE RANGE 0273-0400 K
VELOCITY