Nuclear physics

Nuclear physics is basically just the study of the complex outcomes of weak interaction + quantum chromodynamics.

A proton or a neutron.

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:

Uranium emits them, you can see their mass to charge ratio under magnetic field and so deduce that they are electrons.

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:

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.

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!

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.

Uranium vs plutonium: Section "Uranium vs plutonium Quora answer by Ciro Santilli".

More fun nuclear stuff to watch:

The B Reactor of the facility produced the plutonium used for Trinity and Fat Man, and then for many more thousand bombs during the Cold War. More precisely, this was done at

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:

Reactor of the Hanford site of the produced the plutonium used for Trinity and Fat Man.

The first human-made nuclear chain reaction.

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.

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.

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.