Ion microprobe improvements in Tandetron Laboratory NPI CAS: Numerical calculation

0509714 - ÚJF 2020 RIV NL eng J - Journal Article
Romanenko, Oleksandr V. - Ponomarev, A. G. - Macková, Anna - Havránek, Vladimír - Ponomarov, A.
Ion microprobe improvements in Tandetron Laboratory NPI CAS: Numerical calculation.
Nuclear Instruments & Methods in Physics Research Section B. Roč. 458, č. 11 (2019), s. 77-81. ISSN 0168-583X. E-ISSN 1872-9584
R&D Projects: GA MŠMT EF16_013/0001812; GA ČR(CZ) GBP108/12/G108; GA MŠMT LM2015056
Institutional support: RVO:61389005
Keywords : nuclear microprobe * spaced triplet * acceptance * spatial resolution
OECD category: Nuclear physics
Impact factor: 1.270, year: 2019
Method of publishing: Limited access
https://doi.org/10.1016/j.nimb.2019.08.007

Ion scanning microprobe was implemented in the Tandetron Laboratory, Nuclear Physics Institute of the Czech Academy of Sciences (NPI CAS) in Rez in 2009. Rez microprobe is coupled with a tandetron accelerator, which provides ions from hydrogen to gold, and able to focus heavy ions with the maximum mass energy product at the level 11 MeV amu/q(2). Therefore, microprobe can be used for polymers irradiation by protons and helium as well as for irradiation of various types of glass and other materials with heavy ions. The number of applications for the microprobe in the Tandetron Laboratory is constantly increasing, that leads to the necessity to raise the efficiency of the microprobe operation. Increasing the beam current density allows for a reduction in the time per experiment in relation to recording the number of events. The present work is an attempt to improve the parameters of existing ion scanning microprobe based on a compact Oxford triplet lens system. Since the microprobe is used to investigate both thin and thick targets, the position of the detectors that can restrict the microprobe construction were taken into account in the calculation. The collimated acceptance of the probe-forming system was selected as an objective function as it takes into account both chromatic and all spherical aberrations. Two methods for improving the microprobe parameters were considered. The first one is based on separation of the first lens in the system, whilst the second - on decreasing the working distance. Both ways need changing in the microprobe construction, but the last one requires a major alteration in a target chamber. The benefits of each way were studied. Obtained parameters of the new probe-forming system have shown a two fold increase of the current density of the given probe size for Rez microprobe in comparison with the present system. The benefits of the displacement of the first lens disappear with the decreasing of the working distance.
Permanent Link: http://hdl.handle.net/11104/0300362