Nuclear Science Primer
Preparing oneself (or one’s students) for visiting National Superconducting Cyclotron Laboratory (NSCL)
By Zach Constan, firstname.lastname@example.org, 517-908-7363
Resources one could use before coming for the tour
- Look around the Public Education pages of our website
- A fabulous article for teachers that really prepares one for learning more about NSCL
- A great book about Nuclear Science (most general one I can find): “Introduction to Nuclear Science” by Jeff C. Bryan
- Online resources that include some nuclear instruction
- A nuclear science lesson with activities and demonstrations (Physics Teacher article)
- “Isotopolis”, an iPad-based game about rare isotope research (soon on other platforms)
- “Up From Nothing”, a history of cyclotron laboratories at MSU
- The NSCL brochure
Some useful YouTube videos
- The Rare Isotope Rap (5 min music video about our laboratory)
- The Small Matter of Big Science (45 min documentary about the history of nuclear science, featuring our laboratory starting at 38:43)
What students should know coming in
- Everything is made of atoms, which are made of Protons, neutrons, electrons
- There are many elements in our universe: The periodic tableWhat they will learn about NSCL research
- Nucleus is the core of the atom
10,000 times smaller than the atom itself, contains >99.9% of the mass
Too small for the most powerful microscopes to see
Building block of all matter!
- We study rare isotopes (unstable nuclei that don’t exist on earth) trying to answer:
Which ones can exist, and for how long?
How much do they weigh?
What shapes do they have?
What are the rules (forces) that govern a nucleus’ existence?
- Our job: study nuclei that are too small to see, aren’t found on earth, exist for less than a second, and give off radiation. Not easy, which is why big laboratories are necessary!
Why do we study the nucleus?
What can nuclei do, and what can’t they do? We seek a basic understanding of what we’re made of.
Discover isotopes that have never been observed by humans
Understand the “nuclear force” that binds protons and neutrons together
- Rare unstable nuclei don’t exist on earth, but can exist in stars! They can help us learn:
How do stars shine, evolve, and die (explode – a supernova)?
Where did the elements in our universe come from?
What is causing some neutron stars to emit tons of x-rays?
- How do we use what we learn?
Medicine – most medical imaging technologies (x-rays, CAT and PET scans, MRI) were invented to study the nucleus, and later adapted to look inside the human body. Radiation is used as a diagnostic tool and sometimes to treat cancer.
Archaeology/Geophysics – by measuring what kind of isotopes are in objects, you can tell where they are from and when they formed
Nuclear power – 20% of the electricity in the US is generated from nuclear fission
Smoke detectors, border security devices, solid-state electronics (smartphones)…
- How do we study the nucleus?
Accelerate normal (stable, common) nuclei to about half the speed of light
Smash the “fast beam” of nuclei into a target. Beam nuclei that hit target nuclei will fragment, losing some protons/neutrons and maybe becoming a rare isotope
We only study one kind of rare isotope at a time, so magnets are used to separate/filter all the other isotopes out of the beam
Detectors pick up evidence of the nucleus, allow us to measure it
- Glossary of terms
- Proton – positively-charged particle
- Neutron – particle with about the same mass as proton, but no charge
- Nucleus – core of an atom, composed of protons and neutrons
- Element – type of matter as defined by the number of protons in the nucleus (e.g. an “atomic number” of 6 protons = carbon)
- Isotope – variety of an element as defined by the number of neutrons in the nucleus (e.g. 6 neutrons in a carbon nucleus = carbon-12, the isotope being 12, the sum of protons and neutrons)
- Stable nucleus – a favorable combination of protons and neutrons that will exist forever, barring outside influence
- Unstable/radioactive nucleus – a combination of protons and neutrons that doesn’t last forever. In time, it will “decay” (give off radiation) and often change into a different kind of element/isotope (by altering the number of protons/neutrons, respectively).
- Rare isotope – variety of an element that is unstable and thus unlikely to be found on earth. Mostly found where nuclear reactions are currently making new nuclei (e.g. stars)
- Half-life – The time it would take for half a sample of unstable nuclei to decay. Effectively a measure of how unstable a particular nucleus is: very unstable nuclei have a short half-life.
- Fragmentation – a method of changing a nucleus by smashing it into another one, thus breaking off protons and neutrons. This is a way to make rare isotopes from stable ones
- Cyclotron – a particle accelerator. A large machine that uses magnetic fields to steer nuclei in a circle (hence, “cyclo”) and electric fields (high voltage) to accelerate them. Nuclei must be accelerated to high energies for fragmentation to be successful.
- Superconductor – a wire that, when cooled to a low enough temperature, offers no resistance to electricity. Thus, it can carry large amounts of current and waste none of that energy as heat.