Lillian Croghan
Pronouns: she/her
Research Mentor(s): Louise Willingale
Co-Presenter:
Research Mentor School/College/Department: Electrical Engineering and Computer Science / Engineering
Presentation Date: April 20
Presentation Type: Poster
Session: Session 6 – 4:40pm – 5:30 pm
Room: League Ballroom
Authors: Lillian Croghan, Louise Willingale, Brendan Stassel
Presenter: 81
Abstract
8CB (4’-Octyl-[1,1’-biphenyl]-4-carbonitrile) liquid crystals have been demonstrated as ideal targets for high intensity laser experiments because of their low cost, high repetition rate, replaceability, and small amounts of debris that could interfere with experiments. The University of Michigan’s ZEUS (Zettawatt-Equivalent Ultrashort Pulse Laser System) will perform experiments to study topics of current interest including ion acceleration and relativistic transparency, utilizing thin film targets. The Linear Slide Target Inserter (LSTI) presented in this paper, based on the design from the Scarlet laser facility of Ohio State University (Poole et al., 2016), is designed to eliminate the need to replace and realign pre-made films in vacuum after each use. While replacing a traditional laser target requires inserting and aligning a new target, then cycling its vacuum, the LSTI can operate fully within a vacuum, producing films in succession without replacement. Utilizing a wiper over a small aperture, liquid crystal films can be formed with consistent thicknesses. Moreover, the film thickness can be controlled to a high degree of accuracy. The LSTI accomplishes this with a motor-powered wiper system. By controlling the motor speed and monitoring temperature, the thickness of the liquid crystal thin films can be regulated. A white light interferometer was used to measure liquid crystal film thicknesses depending on motor speed. This presentation will present the LSTI design as well as its corresponding thin film interferometry thickness data. References: P. L. Poole, C. Willis, G. E. Cochran, R. T. Hanna, C. D. Andereck, and D. W. Schumacher, “Moderate repetition rate ultra-intense laser targets and optics using variable thickness liquid crystal films”, Appl. Phys. Lett. 109, 151109 (2016) https://doi.org/10.1063/1.4964841.
Engineering
