Nuclear physics is basically just the study of the complex outcomes of weak interaction + quantum chromodynamics.
Side effect of the strong force that in addition to binding individual protons and neutrons as units, also binds different protons and neutrons to one another.
Ciro Santilli finds it interesting that radioactive decay basically kickstarted the domain of nuclear physics by essentially providing a natural particle accelerator from a chunk of radioactive element.
The discovery process was particularly interesting, including Henri Becquerel's luck while observing phosphorescence, and Marie Curie's observation that the uranium ore were more radioactive than pure uranium, and must therefore contain other even more radioactive substances, which lead to the discovery of polonium (half-life 138 days) and radium (half-life 1600 years).
Most of the helium in the Earth's atmosphere comes from alpha decay, since helium is lighter than air and naturally escapes out out of the atmosphere.
Wiki mentions that alpha decay is well modelled as a quantum tunnelling event, see also Geiger-Nuttall law.
As a result of that law, alpha particles have relatively little energy variation around 5 MeV or a speed of about 5% of the speed of light for any element, because the energy is inversely exponentially proportional to half-life. This is because:
- if the energy is much larger, decay is very fast and we don't have time to study the isotope
- if the energy is much smaller, decay is very rare and we don't have enough events to observe at all
- youtu.be/_f8zeEI0oys?t=796 George Gamow and Edward Condon proposed the quantum tunnelling explanation
- youtu.be/_f8zeEI0oys?t=1725 worked out example that predicts the half-life of polonium-210 based on its emission energy
Caused by weak interaction TODO why/how.
The emitted electron kinetic energy is random from zero to a maximum value. The rest goes into a neutrino. This is how the neutrino was first discovered/observed indirectly. This is well illustrated in a decay scheme such as Figure "caesium-137 decay scheme".
Most commonly known as a byproduct radioactive decay.
A decay scheme such as Figure "caesium-137 decay scheme" illustrates well how gamma radiation happens as a byproduct of radioactive decay due to the existence of nuclear isomer.
Gamma rays are pretty cool as they give us insight into the energy levels/different configurations of the nucleus.
They have also been used as early sources of high energy particles for particle physics experiments before the development of particle accelerators, serving a similar purpose to cosmic rays in those early days.
But gamma rays they were more convenient in some cases because you could more easily manage them inside a laboratory rather than have to go climb some bloody mountain or a balloon.
The positron for example was first observed on cosmic rays, but better confirmed in gamma ray experiments by Carl David Anderson.
Example: Figure "caesium-137 decay scheme"
The half-life of radioactive decay, which as discovered a few years before quantum mechanics was discovered and matured, was a major mystery. Why do some nuclei fission in apparently random fashion, while others don't? How is the state of different nuclei different from one another? This is mentioned in Inward Bound by Abraham Pais (1988) Chapter 6.e Why a half-life?
The term also sees use in other areas, notably biology, where e.g. RNAs spontaneously decay as part of the cell's control system, see e.g. mentions in E. Coli Whole Cell Model by Covert Lab.
Some of the most notable ones:
- 1942: Chicago Pile-1: the first human-made nuclear chain reaction.
- 1943: X-10 Graphite Reactor: an intermediate step between the nuclear chain reaction prototype Chicago Pile-1 and the full blown mass production at Hanford site. Located in the Oak Ridge National Laboratory.
- B Reactor produced the plutonium used for Trinity and Fat Man.
TODO can you do Stern-Gerlach experiment with alpha particles?
Ciro Santilli once visited the chemistry department of an university, and the chemists were obsessed with NMR. They had small benchtop NMR machines. They had larger machines. They had a room full of huge machines. They had them in corridors and on desk tops. Chemists really love that stuff. More precisely, these are used for NMR spectroscopy.
Basically measures the concentration of certain isotopes in a region of space.
- only works with an odd number of nucleons
- apply strong magnetic field, this separates the energy of up and down spins. Most spins align with field.
- send radio waves into sample to make nucleons go to upper energy level. We can see that the energy difference is small since we are talking about radio waves, low frequency.
- when nucleon goes back down, it re-emits radio waves, and we detect that. TODO: how do we not get that confused with the input wave, which is presumably at the same frequency? It appears to send pulses, and then wait for the response.
- youtu.be/uNM801B9Y84?t=41 lists some of the most common targets, including hydrogen and carbon-13
- youtu.be/uNM801B9Y84?t=124 ethanol example
- youtu.be/uNM801B9Y84?t=251 they use solvents where all protium is replaced by deuterium to not affect results. Genius.
- youtu.be/uNM801B9Y84?t=354 usually they do 16 radio wave pulses
The equation is simple: frequency is proportional to field strength!
Used to identify organic compounds.
Seems to be based on the effects that electrons around the nuclei (shielding electrons) have on the outcome of NMR.
So it is a bit unklike MRI where you are interested in the position of certain nuclei in space (of course, these being atoms, you can't see their positions in space).
Using NMR to image inside peoples bodies!
- youtu.be/TQegSF4ZiIQ?t=326 the magnet is normally always on for the entire lifetime of the quipment!
- youtu.be/TQegSF4ZiIQ?t=465 usage of non-ionizing radiation (only radio frequencies) means that it is very safe to use. The only dangerous part is the magnetic field interacting with metallic objects.

Ciro Santilli is mildly obsessed by nuclear reactions, because they are so quirky. How can a little ball destroy a city? How can putting too much of it together produce criticality and kill people like in the Slotin accident or the Tokaimura criticality accident. It is mind blowing really.
More fun nuclear stuff to watch:
- Dr. Strangelove (1964)
- en.wikipedia.org/wiki/Chernobyl_(miniseries)
- The World Of Enrico Fermi by Harvard Project Physics (1970)
- Fat Man and Little Boy (1987) shows a possibly reasonably realistic of the history of the development of the Trinity
- youtu.be/8uIPQBOCJ64?t=2946 talks about the difference between tactical and strategic nuclear weapons
- youtu.be/8uIPQBOCJ64?t=3291 mentions variable yield devices, this is the main new thing Ciro Santilli learned from this video
- youtu.be/8uIPQBOCJ64?t=3416 discusses if a strategic nuclear weapon usage would inevitably lead to tactical nuclear weapon escalation. It then mentions one case in which a possibly comparable escalation didn't happen: the abstainance of using chemical weapon during World War II.
Located in Washington, in a dry place the middle of the mountainous areas of the Western United states, where basically no one lives. The Columbia river is however nearby, that river is quite large, and provided the water needed by their activities, notably for cooling the nuclear reactors. It is worth it having look on Google Maps to get a feel for the region.
Unlike many other such laboratories, this one did not become a United States Department of Energy national laboratories. It was likely just too polluted.
Bibliography:
Mostly the daily life part of things, but very good, includes subtitles explaining the people and places shown.
Marked with identifier "LA-UR 11-4449".
The first human-made nuclear chain reaction.
- youtu.be/mnScq24BEmc?t=114 the main cost for the reactor was the graphite. Presumably they already had the uranium in hand?. Edit, no, it is because it was a specialized graphite: Video 2. "German graphite from The Genius Behind the Bomb (1992)", i.e. nuclear graphite.
The lab that made Chicago Pile-1, located in the University of Chicago. Metallurgical in this context basically as in "working with the metals uranium and plutonium".
Given their experience, they also designed the important X-10 Graphite Reactor and the B Reactor which were built in other locations.
Plutonium-based.
Its plutonium was produced at Hanford site.
- Gun-type fission weapon were much easier to build as you don't need super synchronized charges as in implosion-type fission weapon. But they are less efficient.
- Plutonium make much more efficient usage of uranium, because you don't need to highly enrich a bunch of Uranium-235 in the first place, but rather just use way less enriched Uranium-235 to produce a bunch of Plutonium by converting Uranium-238
Their website, and in particular the recruitment section, are so creepy.
There's not mention of bombs. No photos of atomic explosions. The words "atomic" and "weapon" do not even show up in the front page!!! The acronym AWE is instead used everywhere as an euphemism.
In the recruitment section we can see a bunch of people smiling: web.archive.org/web/20211007213222/https://www.awe.co.uk/careers/working-at-awe/, suggesting:
We make nukes, and we do it with a smile!There's even children outreach!!!
Ciro Santilli is not against storing a few nukes to be ready against dictatorships. But don't be such a pussy! Just say what the fuck you are doing more clearly! You are making weapons to kill people and destroy things in order to maintain the Balance of power. If the public can't handle such facts, then shut down the fucking program.
Knock knock.
Documentary about American ICBM crews working on the Francis. E. Warren Air Force Base. Wiki mentions that there are 3 main sites in the USA, and plainshumanities.unl.edu/encyclopedia/doc/egp.ii.042 suggests all/most of them are in the Great Plains area. They operate a Minuteman system, which as of 2021 is the only nuclear ICBM system in the USA.
Good documentary, shows well the day-to-day life of the operator, including outside of the work site.
- youtu.be/w1tMx27Q4O0?t=1390 they drive 100 miles to get to work. They do 8 alerts per month.
- youtu.be/w1tMx27Q4O0?t=1473 the actual missiles are a few miles away from the control center, scattered in a few different locations
- youtu.be/w1tMx27Q4O0?t=1619 they have a television in there at least. Presumably a pre-recorded selection.
Ah, the choice of name, both grim and slightly funny, Dr. Strangelove comes to mind quite strongly.
Ciro Santilli's jaw dropped when he learned about this concept. A Small Talent for War, are you sure?
plutonium-based.
Its plutonium was produced at Hanford site.
uranium-based, dropped on Hiroshima. The uranium was enriched at the Clinton Engineer Works.