A multiple foil holder for use in ultra high vacuum (UHV) environment as a post accelerator ion stripper has been designed and fabricated. It is used to produce beams of an ion in different charge states at a given energy from a 14 MV pelletron accelerator. These ions are required in several types of atomic collision experiments. The assembly is tested with³²S ions at various energies.

A facility for carrying out beam-foil spectroscopic studies in the UV and visible region using the 400 kV electrostatic ion accelerator at Tata Institute of Fundamental Research, Bombay is described.

Beam-foil spectrum of fluorine was recorded in the wavelength region of 2000–4500 Å using F⁺ ion beams of energies ranging from 216 to 296 KeV. Some of the spectral lines of fluorine observed during the present investigation are hitherto unknown. Mean lifetimes of a few of the excited levels of F II and F III are reported for the first time.

An electrostatic charge state selector has been constructed for charge transfer studies in ion atom collisions. Its design and performance have been discussed illustrating with examples of some data taken using heavy ion beams from the pelletron accelerator. Expressions for the determination of charge state fractions from the observed charge spectrum in voltage scanning mode of operation and also the line shapes have been discussed analytically in detail.