Event
Prroposal Exam: Stefan Waczynski
Friday, May 26, 2023
1:00 p.m.
IREAP Large Conference Room
Maria Hoo
301 405 3681
mch@umd.edu
ANNOUNCEMENT: PhD. Research Proposal Exam
Name: Stefan Waczynski
Committee:
Professor Dr. Howard Milchberg (Chair)
Professor Dr. Phillip Sprangle
Professor Dr. Julius Goldhar
Date/time: 5/26/2023 1 pm
Location: IREAP Large Conference Room
Title: Mid-IR Laser Driven Avalanche and its Applications to Radiation Detection & Plasma Gratings
Abstract:
Laser driven avalanche where a high-intensity pulse ionizes and drives breakdowns from ambient ion concentrations has not been studied in much detail since the late 60s where it was the predominant mechanism for laser-driven breakdowns/plasma as it has been superseded by ultra-short-pulse driven multi-photon ionization effects. However avalanche is amenable to readily available low-intensity long-pulse off-shelf laser systems, which open up applications that MPI-dominated systems are not able to support.
The current state of the art in radiation detection is the close-distance Geiger counter which requires direct exposure to radioactive decay particles and photons. A potential solution to remote detection of radiation is through Mid-IR driven avalanche seeded by ions produced by the radiation source. In order to properly simulate and predict the behavior of this detection mechanism, we must study the behavior of ambient negative air ion concentrations. Here we present experimental data showing the generation and recombination time-constants for negative air ions in the presence of a Po-210 radiation source. These results are supported with simulations based on previous theoretical work on radiation-generated ion concentrations. We also report further progress in the field of radiation detection with Mid IR laser-driven avalanche as well as experimental work scaling the technique to 10 microns.
