Applications of Nuclear Techniques Flashcards
The 3 pillars of the Non-Proliferation Treaty?
- Prevention of the spread of nuclear weapons.
- Promotion of the peaceful use of nuclear energy.
- Goal of achieving mutual nuclear disarmament.
The 5 nuclear weapons states?
UK, France, Russia, China and the USA.
What is the role of safeguard inspectors?
Inspect sites involved with the processing of nuclear material to check the state’s compliance with the NPT.
How are isotopic ratios measured?
Using gamma-ray spectroscopy on samples (think the experiment)
What is secular equilibrium for a sample?
When the production rate of a radioisotope is the same as its decay rate. Occurs when the half life of the daughter nuclide is much shorter than the parent.
What is enrichment?
The process of changing the isotopic balance of uranium, to add more fissile material.
What is self absorption?
When a material acts as an absorber of the neutrons produced by its own radioactive decay, serving to reduce the apparent sample activity.
What does it mean for a sample to have infinite thickness?
Its thickness is greater than 7/μ, and after this point its count rate observed on a detector is independent of its thickness d.
What is the intrinsic calibration method?
For a sample with multiple γ ray energies and known intensities per disintegration, the ratio of experimental yield to theoretical yield gives the self absorption factor at different energies.
Main principle of carbon dating?
Living organisms are constantly exchanging radioactive C-14 with their surroundings, but stop when they die. By comparing activity with that of a calibrated sample of known age, it is possible to date the sample up to an age of about 10 half lives (57000 years)
What is β counting?
The direct measurement of β particles from the decay of C-14. Measurements are made of the sample activity, standard activity and the background (an old sample with no C-14).
What is accelerator mass spectrometry (AMS)?
C-12 and C-14 have different masses, so when deflected in a magnetic field have different deflection amounts and become two separate beams. Allows for direct counting of atoms.
What is the Suess Effect?
Carbon from fossil fuels has no C-14 as it is so old, so it dilutes the atmospheric ratio of C-14 to C-12 - needs to be accounted for when comparing to a background.
Principle of rubidium-strontium dating?
Rb-87 decays to Sr-87 with a 48 billion year half life. Geological processes cause different behaviour of the two elements during rock formation. Comparing the ratio of the two elements for several samples of the same rock can yield info about when the rock formed.
What is an isochron?
A straight line with gradient e^λt - 1
