Beam-single and beam-two-foil experimental facility to study physics of highly charged ions

Abstract

Formation of doubly positively charged diatomic ions of Mo 2 2+ produced by Ar + sputtering of an Mo metal surface Resonance ionization spectroscopy investigations of electronic processes during ion-beam sputtering of metal atoms AIP Conf.A facility for lifetime measurement of metastable states in highly charged ions using the beam-foil technique with a single-foil and a two-foil target has been developed. In the two-foil technique, one foil moves with respect to the other and the option of varying the thickness of the fixed foil online has been implemented. A holder with multiple foils is used as a fixed target, and moved along x, y, and , the angle of rotation with respect to beam direction along the z axis. Using this facility, the He-like 1s2p 3 P 2 o and Li-like 1s2s2p 4 P 5/2 o titanium lifetimes have been measured and compared with earlier values. In addition to this, the processes which occur when excited states collide with carbon foils of different thicknesses have also been investigated. Preliminary results suggest the scope of studying intrashell transitions during ion-solid collision using this setup. In this article, the setup is described in detail and representative results are briefly discussed.

Note: Multi channel Doppler tuned spectrometer to study highly charged ions

“…However, this technique suffers from inherent cascading and blending problems. 3 By combining beam single foil and beam two foil techniques, Ahmad et al 4 have shown that the above mentioned complexity can be disentangled to a certain extent. 5 The Doppler tuned spectrometer (DTS) 6, 7 is a high resolution, high efficiency setup and hence suitable for the study of x-ray emission from metastable states, created by beam-foil interaction.…”

“…A unique Soller slit assembly coupled with a long one dimensional position sensitive proportional counter enables us to get distinct x-ray peaks at different angles, which allows us to cover large number of angle in one shot. By using this setup, 1s2s 3 S 1 -1s 2 1 S 0 M1 transition in He-like Fe has been resolved from its satellite line 1s2s2p 4 The beam-foil spectroscopic (BFS) 1, 2 technique is one of the most elegant tools to study highly charged ions (HCI). However, this technique suffers from inherent cascading and blending problems.…”

“…1 (top). To test the performance of this setup, an endeavour has been made to resolve the 1s2s 3 S 1 -1s 2 1 S 0 M1 transition in He-like Fe and its satellite 1s2s2p 4 M2 transition in Li-like Fe and to measure the lifetime of corresponding upper levels. A beam of 165 MeV 56 26 F e +12 ions was used for the experiment.…”

Collision-induced intra-shell transitions in He-like ions

“…The experiment was performed using the 15 UD tandem Pelletron accelerator at IUAC, New Delhi. A schematic of the experimental setup used is shown in the inset of figure 1 and details are given elsewhere (Ahmad et al 2006). A beam of 48 22 Ti 11+ at 143 MeV was passed through a carbon foil of about 60 μg cm −2 (first foil) to produce the excited states in highly charged ions.…”

“…The agreement between the two methods was found within less than 10%. The flat carbon foils were fabricated by a special technique (Ahmad et al 2006) so that a capacitance-measuring arrangement can be used to measure the distance between the two parallel foils up to 83 ± 1 μm. The maximum distance was used up to 40 mm.…”