Experimental and computational investigation of tin interaction with hydrogen gas

Stahl, Jack Thomas

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https://hdl.handle.net/2142/116287 Copy

Description

Title

Experimental and computational investigation of tin interaction with hydrogen gas

Author(s)

Stahl, Jack Thomas

Issue Date

2022-07-22

Director of Research (if dissertation) or Advisor (if thesis)

Ruzic, David N

Committee Member(s)

Sankaran, Mohan

Department of Study

Nuclear, Plasma, & Rad Engr

Discipline

Nuclear, Plasma, Radiolgc Engr

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• tin
• hydrogen
• plasma
• ion
• scattering
• RustBCA
• ion gun

Abstract

Extreme ultraviolet light sources, which are used in industry to produce top-of-the-line computer chips, are susceptible to short lifetimes due to tin build-up inside the machines. Tin, which generates the light, coats sensitive components inside the source vessel after being struck with a high-power laser. Hydrogen is used as a buffer gas to prevent tin from reaching the walls, but the mechanisms of the tin and hydrogen interactions are poorly understood. In this thesis, these interactions are studied computationally and experimentally. A computer model was built using density-functional theory to generate Sn − H2 and Sn2+ − H2 interaction potentials which were implemented in scattering code RustBCA. Results from the computer model were compared against other common models, which generally showed that tin travels farther in hydrogen at energies below 10 keV and less far at energies above 10 keV than previously thought. An experiment was built with a Faraday cup to measure tin ion current generated by an ion gun at several of ion energies in the HARP vacuum system. Energies from 500 to 1250 eV were measured and the cross section was calculated from the data. The experimental measurements generally showed a cross section larger than the model’s cross section by a factor of 5, which in turn was larger than other measurements in literature. Hydrogen plasma generated with a helicon was also compared against hydrogen gas, and the plasma stopped the tin ion beam slightly more efficiently. Systemic biases and measurement uncertainties in the experimental results suggest that more work is needed in this area.

Graduation Semester

2022-08

Type of Resource

Thesis

Copyright and License Information

Copyright 2022 Jack Stahl

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