Nuclear Physics Seminars

ics Nuclear
Tuesday, April 24, 2018
3:30 PM
Physics Building, Room 204
Sina Tafti [Host: Gordon Cates]
UVA - Department of Physics
"1. Toward Spin-Polarized Nuclear Fusion: MRI of Laser-Polarized He-3 Permeating Through Polymer-Shell Tokamak Pellets 2. A Novel Method of Defining Emphysema Index Using MRI of Laser-Polarized Noble Gases in the Lungs"

I will share two applications of spin-polarized noble gas imaging using magnetic resonant imaging. To date, self-sustained fusion energy production has not been achieved since the energy spent in containing the plasma favorable for fusion reaction surpasses the energy outcome. Spin-polarized fusion (SPF) promises a 50% boost in fusion cross section between deuterium and tritium (or He-3). However, SPF has not been experimentally tested in a reactor for several logistical challenges related to delivery of polarized fuels to the plasma.

In collaboration with General Atomics and JLab, we propose to optimize and measure polarization survival of spin-polarized He-3 during permeation into polymer-shelled inertial-confinement fusion (ICF) pellets, a crucial step toward achieving SPF. Granted that adequate polarization survival into the pellets is achieved, the SPF reaction of D and 3He will be tested in the General Atomics D-III D Tokamak which would be the very first experimental demonstration of SPF in a fusion energy reactor.

CT has been the golden standard imaging technique to characterize and quantify emphysema, however, it exposes the body to ionizing radiation. An alternative image based method of characterizing emphysematous lung tissue is by having the patient inhale spin-polarized noble gas (He-3 or Xe-129) and image the gas inside the lungs. Since diffusion of the gas molecules inside the lungs are constrained by the microstructure of the lungs, how far gas molecules travel can tell us about regional tissue destruction due to emphysema. Here we introduce a novel method of defining emphysema index based on apparent diffusion coefficient maps acquired using a diffusion-weighted MRI pulse sequence.

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