1. Focal overlap gating in velocity map imaging to achieve high signal-to-noise ratio in photo-ion pump-probe experiments.
- Author
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Shivaram, Niranjan, Champenois, Elio G., Cryan, James P., Wright, Travis, Wingard, Taylor, and Belkacem, Ali
- Subjects
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SIGNAL-to-noise ratio , *PUMP probe spectroscopy , *ELECTRODES , *LASER beams , *X-rays - Abstract
We demonstrate a technique in velocity map imaging (VMI) that allows spatial gating of the laser focal overlap region in time resolved pump-probe experiments. This significantly enhances signal-to-noise ratio by eliminating background signal arising outside the region of spatial overlap of pump and probe beams. This enhancement is achieved by tilting the laser beams with respect to the surface of the VMI electrodes which creates a gradient in flight time for particles born at different points along the beam. By suitably pulsing our microchannel plate detector, we can select particles born only where the laser beams overlap. This spatial gating in velocity map imaging can benefit nearly all photo-ion pump-probe VMI experiments especially when extreme-ultraviolet light or Xrays are involved which produce large background signals on their own. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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