Collinear photodetachment spectroscopy
Abstract
A new ion beam apparatus, designed for collinear photodetachment experiments, has been constructed. Negative ions are formed on a surface ionizer, mass selected in a sector magnet and directed into a field-free region where they are merged with a laser beam along a 50 cm long path. A new secondary electron emission detector has been constructed in order to detect neutral atoms formed in the photodetachment process. The design of the detector makes it possible to use pulsed lasers which, in combination with a gated detection, gives a very good signal-to-background ratio. In a first experiment, the electron affinity of atomic iodine has been determined to be 3.059038(10) eV. The onset of the photodetachment process was observed when the wavelength of the laser light was scanned, and the result was fitted to the Wigner law in order to determine the photodetachment threshold.
- Publication:
-
Nuclear Instruments and Methods in Physics Research B
- Pub Date:
- June 1993
- DOI:
- 10.1016/0168-583X(93)95313-T
- Bibcode:
- 1993NIMPB..79..159H