Brainiac Book Reviews: Nuclear Photo-Disintegration, by J. S. Levinger
November 1, 2013
(Nuclear Photo-Disintegration, by J. S. Levinger. Oxford University Press. 1960.)
This book contains discussions of methods of calculation for atomic and nuclear photo-effects; the deuteron photo-effect; sum-rule calculations for nuclear photo-disintegration; and a bunch of other stuff a little bit over the heads of some of you. Nevertheless, we can assume it’s important. And if any parts of the book are obsolete because of the passage of time, that’s okay. Ideas sometimes go out of favor and then come back, so you never know.
Chapter One is “Interactions Between Charged Particles and Radiation.” There are three ways to measure this sort of thing: the Heisenberg approach; the perturbation-theoretic approach in which the electromagnetic field is treated classically; and the approach of quantum electrodynamics. The author likes the second approach best, and I agree with him. You have some nice classical music going in the background, you’re going to do a better job.
There are a lot of equations of oscillator strength, but they’re mainly a waste of time. If you’ve got an oscilloscope, you can see with your own eyes what the strength is. It doesn’t have to be exact.
The author points out that from the orthogonality of spherical harmonics, the final state must be a P state in agreement with the well-known selection rule Delta l = plus or minus 1. The Clebach-Gordon coefficients explain this, as you probably know.
Siegert’s theorem is a good thing to learn, but I can’t write it out here. You can look it up somewhere and carry it in your wallet, because you never know when it might come in handy.
Early workers on photo-disintegration measured the partial cross sections for production of one radioactive nucleus or another, mainly to keep themselves employed.
Chapter Two is “Photo-Disintegration of the Deuteron.” You can’t even buy deuterons anywhere, so I don’t see the point, really. The author points out that “measurements using continuous bremsstrahlung spectra do not have to be treated by the photon-difference method.” Okay, big deal. I think the author is showing off a bit with this bloated German terminology. I never even heard of bremsstrahlung spectra (although the amazing thing is that the spell-check on this page isn’t even flagging it!).
On page 38 there is a graph about the deuteron photo-effect. It goes up, then slides down, and then it recovers a bit and then drops off. But what happens after that? I mean, the universe doesn’t come to a stop just because a graph does. We’re dealing with huge power here, people. This could be dangerous. These scientists have to watch everything going on in their labs. Any distraction — especially female — could result in an explosion. On page 47 there’s another graph that’s heading toward the upper right at a sharp angle. Where’s that going to? Jupiter? This one is based on the calculation of deSwart and Marshak. We don’t know those guys. They could have been Commies. Hey, it’s no joke. This was during the Cold War. Science labs were crawling with spies and traitors passing stuff to the Russkies. Now, of course, it’s the slitty-eyed Chink bastards we have to worry about.
There’s a section on Mesonic effects, which may be related to Freemasonry, so I recommend that you just skip over it.
Chapter Three is “Sum-Rule Calculations.” Now bear in mind that when this book was written, pocket calculators hadn’t even been invented yet. We all used slide rules. So this is sort of a nostalgia chapter. The author says, “While Migdal’s calculation was stated in terms of a collective model of protonic and neutronic fluids, it applies equally well to the ‘shell model’ of two perfect Fermi gases.” Yeah, the Fermi gases were cool in those days. I remember this prof in atomic physics who was so into Fermi gases that everyone knew that’s what his exams would be on, so we all got A’s. This prof also had this novelty necktie with four different designs, and he could put it on so as to show any one of the four designs.
There’s another real threatening chart on page 55, and I know that if I had the time, I could use it to make some kind of energy weapon and I could zap all the ugly wogs on Sherbourne Street (and all the obnoxious gamers here in the lounge with me right now). I’m sure the U.S. government has some exotic weapons they’re not telling us about.
There’s a long discussion on the shell model, which nobody really uses any more, but it brings back memories of the good, old days.
Chapter Four is “Discrete Transitions.” The author refers to a lot of other people who supposedly agree on this stuff. When everyone agrees on something, that’s when you should be suspicious. I didn’t like this chapter too much.
Chapter Five is “The Total Cross Section For Photon Absorption.” There’s a real scary chart on page 81, which I will not even attempt to describe. It’s about the energy peak due to photon absorption by the “valence neutron”, and a high energy “giant dipole resonance” due to excitation of the core nucleons. This actually explains global warming and a lot of other things, like why your audio cassettes get snagged in cheap cassette players and also why certain races commit more crime. The author doesn’t mention any of this, but you can take it from me that it’s for real. I’ve done my own research.
There’s a spectacular graph on page 89, and you have to turn the page sideways to view it. The Neutron number goes from 20 to 150. That’s as much as they could fit on the page. (Over 150, I don’t even want to know what happens!) The graph is taken from Okamoto, who I think did special effects for some of those Japanese monster movies.
Chapter Six is “Products of Nuclear Photo-Disintegration.” Well, we know what they are, don’t we? It’s mainly photons. They get spun off in all directions and make pretty colors. The author gives us some equations, but you don’t have to use them. All they mean is that the protons fill up the closed shells to the quantum number N. Another product is neutrons. The lower energy ones have an isotropic angular distribution, so you don’t have to worry about them. The higher energy ones can do some damage, like if they come out of a bomb or something, so you have to wear a lead suit or be ten miles away. Other products only show up on rare occasions, and you won’t have to deal with them in everyday life.
There’s a long Bibliography and Author Index, and also a Subject Index. They’re both good, and the alphabetical order is correct.
At the time Oxford University Press published this book, they had a lot of foreign offices, including Bombay, Calcutta, and Madras in India; Karachi, Pakistan; Kuala Lumpur, Malaysia; Accra, Ghana; Ibadan, Nigeria; and Nairobi, Kenya. This shows a lot of confidence by the publisher in these inferior people, who apparently have not benefited too much from this book.
Copyright@ 2013 by Crad Kilodney. E-mail: firstname.lastname@example.org
Reminder: my French book, Villes Bigrement Exotiques, is still in print. Published by Le Dilettante (Paris).