10. Radioactive Decay Continued

[@mitocw]

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[@lucyoriginales]

I just wanna say I miss my professor. 🤗 I wish others were like him. Like neurology or neurosurgery. They're stupid what they're teaching. 😔💔😭

[@fieryweasel]

4:10 "It's got to be something not that salty, or fissionable". That's exactly the conditional test I apply to any snack before I try it.

[@davidrudpedersen5622]

5:40 CRUD also stands for Create Read Update Delete in programming

[@jacobjohn378]

Okay.... these guys get to operate reactors in their second year of undergrad. This school is awesome & I am jealous.

[@zack_120]

51:00- 'm and E are the same thing' started making sense via the transitions between m and E of these particles.

[@shikshokio1]

@MIT OpenCourseWare , there is a mistake in the lecture around 1:16:00. The expression for N2 is incorrect. The integration constant C is NOT equal to zero, because then N2 in time zero is not zero, as it should.

[@ducciwucci]

there is a reason that they are at MIT, and you are not.

[@shikshokio1]

@@ducciwucci What do you mean?

[@abebuckingham8198]

@@ducciwucci Everyone makes mistakes, even people at MIT. It's why we have peer review. Critical thinking requires being critical and no scientist wants you to trust them uncritically.

[@NITROUSOXIDE921]

​@@abebuckingham8198while I can't verify the accuracy of his comment, I didn't get the impression he's implying that MIT profs can't make mistakes.

[@1080pMarco]

Looking at those classes "just for fun" in my spare time, makes me really think to dump my soon to be started PhD in Chemistry and getting myself a degree in Nuclear Engineering.

[@danridesbikes7183]

I quit my job as a design engineer to join the nuclear industry after watching these videos... :)

[@randallmcgrath9345]

​@@danridesbikes7183 but wouldn't there be some design jobs in Nuclear as well, given that all these Fusion startups and such?

[@danridesbikes7183]

@@randallmcgrath9345 oh for sure. I was designing parts for Peterbilt class 8 trucks and learned quickly that staring at Creo/Pro-E all day was not for me.

[@randallmcgrath9345]

@@danridesbikes7183 understood.

[@razersparkprime9143]

I don't know how I got here. I was asleep I could hear in my dreams. For some reason my dad was explaining, even though he doesn't do anything in relation to this.

[@jacobjohn378]

Man, that Luke guy is really smart. He does his readings.

[@boarfat3004]

Where is lecture 9 ?

[@mitocw]

Video of Lecture 9 is not available.

[@Ikbeneengeit]

@@mitocw :(

[@truffleshuffl]

@@mitocw can you let us know what we are missing out on so we can do our own research? Is this for legal reasons? What’s the point of continuing watching if I don’t even know what I don’t know?

[@Harbingerof666Doom]

I didn't notice that but I too wanna watch lecture 9 for some research purpose

[@wich1]

@@truffleshuffl I think you’re missing out on nothing. In lecture 8 he mentioned that he would not be present on Thursday, but the TA or TAs would. Instead the Friday lecture would be longer. I expect this is that Friday lecture. The Thursday session would likely not cover any new material.

[@Alphabet_-_]

Alpha decay An alpha particle (A = 4, Z = 2) emitted from nucleus (A − 4, Z − 2) p Proton emission A proton ejected from nucleus (A − 1, Z − 1) 2p Double proton emission Two protons ejected from nucleus simultaneously (A − 2, Z − 2) n Neutron emission A neutron ejected from nucleus (A − 1, Z) 2n Double neutron emission Two neutrons ejected from nucleus simultaneously (A − 2, Z) SF Spontaneous fission Nucleus disintegrates into two or more smaller nuclei and other particles - CD Cluster decay Nucleus emits a specific type of smaller nucleus (A1, Z1) which is larger than an alpha particle (A − A1, Z − Z1) + (A1, Z1)

[@Kingstanding23]

31:00 so could we use a γ emitter as a source for photovoltaics?

[@shawnodonnell3554]

So an isomeric transform involves a gamma photon emitted from the nucleus. The gamma photon might escape unmolested, or it can interact with an electron on the way out. And the photon can 'hit' an electron. What does that mean? It can't 'hit' it head-on. The probability of that must be without measure, like the probability of a specific outcome in a continuous probability distribution. Some sort of glancing 'blow' produces a Compton-like effect, with an electron taking on its binding energy plus whatever Auger kinetic energy it receives, right? Is that why the energy distribution is continuous? And the gamma photon loses a commensurate amount of frequency to make the energy balance work out, right? But in classical physics, the EM wave of the photon would interact with ALL the electrons, at some point. What gives?

[@vedantkashyap5703]

The electrons in the bound state of the atoms tend to absorb the entire energy of the gamma ray photon and the entire energy is absorbed by a single electron. The electron then flies off with the kinetic energy equal to the difference of gamma photon energy and the electron orbital binding energy. Consider it a process similar to photo-emission but just the source of photon is from within the atom rather than an external source. On contrast, a free electron that is not bound to an atomic potential shows Compton effect. Only "a free electron cannot absorb a photon completely," resulting in Compton effect. (Refer to I.E. Irodov problem 5.281 for this result.) The energy distributions shown are NOT of these electrons ejected from the atomic orbitals but instead of electrons FORMED from beta decay (Beta decay and Isomeric transitions generating electrons are different processes). Electrons ejected from atomic orbitals have well defined energy. The energy spectrum of electrons generated from beta decay varies in a range because an electron is always produced with an electron-antineutrino (to conserve lepton number) and hence the Q-value is shared among 2 particles as their kinetic energy. Since the ejected particles are not bound to a potential, they can have continuous kinetic energies (contrary to bound particles having quantize or discrete energies) and some kinetic energy goes to the antineutrino, thus the electron in beta decay shows a continuous energy spectrum. This is also why the electron kinetic energy is never equal to Q. Finally, the choice between Classical and Quantum theory of light. We consider the Quantum theory of light when studying light interacting with particles because that's how nature works and Physics is able to explain the phenomena :)

[@abebuckingham8198]

The particle metaphor is inaccurate. Nothing collides, it's just waves interacting. The only particle-like property is that they are quanta so each wave packet can be counted individually. They don't have a well-defined radius and are instead given a probability of interaction based on proximity. It's analogous to two boats leaving a wake as they travel in the water. If they're close they'll feel the waves of the other and if they're far those waves will be negligible. This happens even though the boats don't collide.

[@justgivemethetruth]

What happened to Lecture #9 ?

[@mitocw]

The lecture 9 video is not available and no reason was noted. From the syllabus, it was about Radioactive Decay and there were assigned readings. See the course materials for more info at: ocw.mit.edu/22-01F16. Best wishes on your studies!

[@lucyoriginales]

Miss u professor 🤗. Thanx.

[@atzuras]

"Auger electrons" are not the O.G. Electrons we love and care.

[@williamlove3087]

Video number 9 is missing! where is it?

[@mitocw]

Lecture 9 is not available. The topic was "Radioactive Decay Continued" and had readings, "[Turner] Sections 4.1 to 4.3, pp. 83-88.". See the course on MIT OpenCourseWare for more info at: ocw.mit.edu/22-01F16. Best wishes on your studies!

[@ManuelCantrellCedilloJrZIV]

What happened if you mix BRASS with nuclear energy?!....😊😊😊😊.

[@idontneedaname85]

I'm mostly confused by the 3 of ten of time thing he keeps saying.

[@neshirst-ashuach1881]

If the class needs to finish at 9:50, for example, then you can say the class needs to finish at "10 of". "Three of ten of" would then be 9:47, 3 minutes before ten minutes before the hour. Its definitely a weird way of saying it. Source: Someone on a previous video explained to me.

[@idontneedaname85]

@@neshirst-ashuach1881 thanks for helping me out with that. Truly appreciate it.

[@mihirvora2010]

The half-life of Tc-99m is actually 6 hours...

[@shuycg]

"Cool". Yeah, he is.

[@ConcreteBombDeep]

I've watched this a few times. The abrasiveness between Short and Ames regarding not putting human biological items in the reactor I find interesting. Why is Ames against putting things like skin flakes and human nails in the reactor? Is that a law or rule or something or what's his prerogative?

[@johnfarmer3506]

If you find a human outcome that has red flag you have to find out why. If you find some uranium 238/ 235 in someone because they where by a new shipment of fuel for the reactor then you got yourself a lot of extra work regardless of the levels detected.

[@kenj0418]

There are a number of rules about privacy, consent, safety, etc. that come into play with experiments involving humans. They were worried that having human samples in the test might make some of those rules apply and it was easier to just avoid it completely.

[@VeteranVandal]

Probably a bureaucratic nightmare happened in the past...

[@distalradius8146]

Human experimentation is a big no-no at most universities. I was quite surprised to learn that I couldn't sequence my own DNA.

[@guiuismo]

This Luke guy

[@FarnhamJ07]

Methinks he should be more careful with jokes about bringing in fissionable materials for their little experiment... Am-241 from smoke detectors is not just fissionable but fissile and I could easily see a smart aleck student doing it to screw with the professors without thinking it through.

[@samueledeko8724]

😖🤔🧐

[@GreatAuntKit]

Tc99M has a half-life of 6 hours not days. That would be annoying for patients receiving i† otherwise.

[@VeteranVandal]

And for using too.