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MARY NORRIS, STEPHENVILLE HIGH SCHOOL
LIN SHAO, ASSISTANT PROFESSORNUCLEAR ENGINEERING TEXAS A&M
UNIVERSITY
The research question: How Does Radiation Affect the Components
in a Nuclear Reactor?
Lin Shao
Education Ph.D., Physics, University of Houston, 2001B.S., Nuclear Physics and Technology, Peking (Beijing) University, P. R. China, 1997
Areas of Interest Materials science and nanotechnology Radiation effects in nuclear and electronic materials Ion beam analysis
Main Research Group: Nuclear Materials and Fuel Cycles
•Pressure vessel
•Pressuerizer
• Steam generator
•Pump
•Containment
Pressurized water nuclear reactor
Uranium Enrichment U-238 U235
Fuel Rod and Fuel Assembly
Fission Reaction Stray neutrons cause damage to the metal of surrounding the fuel rods
VacancyInterstitial
Disloca-tion loop
Cluster
Interstitialcy
Damage at the molecular level
Why we care
In nuclear reactors, many energetic ions keep bombarding reactor walls. This bombardment can cause bubbles, cracks and voids. This makes the reactor unsafe.
We want to know when and how this will happen, but do not want to wait 20 years.
Accelerators are used to simulate the environment
Five accelerators ion energy from 10 keV - 1.7 M eV
Ion Beam Analysis
view port
Ion beam
RBS - Rutherford Backscattering for depth profiles of complex thin films (up to a few microns thick and down to a few nm depth resolution). PIXE- Particle (usually proton) Induced X-ray Emission (ppm sensitivities). NRA - Nuclear Reaction Analysis (isotope specific). IBIC - Ion Beam Induced Charge.STIM - Scanning transmission ion microscopy.
Summer Research
Particle Ion Irradiation Effects on the Venus Flytrap
Leanne Kristek
Gain insights into possible biological effects on living tissue of Venus flytraps
Possible reasons for dysfunction: Trigger hair damage Ion channels inhibited
Identify the critical dose level for noticeable function failure
Understand the signal transfer mechanism in Venus flytraps more comprehensively
Implications
Venus Fly Trap with trigger hairs
Data Collection
Record speed of closure before, after, and possibly during proton and alpha irradiation Use a high speed camera, e64 Hotshot Mic Use SCRIM program to determine
Energies to use Number of damage events for each given energy
View structural tomography before and after irradiation to detect ion-solid interaction damage (especially of ion channels, plasmodesmata, and stomata) Use Scanning Electron Microscope
Question I
If the leaf does indeed close once bombarded with the ion beam, are the ion channels of the plant affected? If so, how? Ion potentials involve Cl−, K+, Ca2+, and H+
If the leaf will not reopen, then how to collect data? Could try using an electrical current to reopen Could try irradiating soil instead of directly on leaf
Accelerator Attachment
- Faraday Cup- Scintillation Crystal- Sample Holder
Faraday Cup
Collects charged particles in a vacuum Minimal to no backscatter
Placed before the Venus Flytrap
Measure the resulting current (I) to determine amount electrons (N) hitting target in time (t):
Scintillation Crystal
Ionizing radiation causes luminescenceThus allowing a visual to focus beam
Questions
Does the ion beam act on the sensitive filaments or the cells of the leaf itself?
Do the trigger hairs and/or cells repair themselves? Signs of repair
Assel Aitkaliyeva George Wei
Tianyi Chen
Danny Galicki
Justin General Josey Wallace
McIan Amos
Ion & Materials Research Facility (Ion Beam Lab, Accelerator Lab)
Lin Shao, Lab Director
students
M.S. students
Undergraduate
Alvaro Aranibar
Leanne Kristek Lloyd Price
Thank You!!!Dr. Shao and his staff have been incredibly welcoming and gracious. They have willingly taken time from their busy schedules to help and answer questions whenever I asked.
Additional Thank You’s
TAMU E3 Program
National Science Foundation
Nuclear Power Institute
Texas Workforce Commission