Bench Degree·NUCLEAR POWERchapter

On the Cover

How the cover of every Bench Degree volume is chosen. One question, and it is not who got there first or who is famous. If we could bring anyone back to teach you this subject, who would you actually want at the bench? That is the whole test. It picks people who did the work with their hands, who checked things themselves, and who would be worth standing next to. Every one of them actually lived, which is why a cover portrait in this series is either a real document or openly a drawing, and never a photograph of something that did not happen.

Lise Meitner, 1878 to 1968, engraved from a portrait she signed and dated 1916.

The reason she is here is not that she was robbed, although she was. She is here because the most consequential result in this subject was obtained with a pencil.

In July 1938 she left Germany with ten marks in her purse, her Austrian citizenship having protected her Berlin post through the 1930s until the annexation of Austria removed the protection. She landed in Stockholm in a laboratory that gave her almost nothing to work with, and she and Otto Hahn kept writing.

That December Hahn and Fritz Strassmann found barium among the products of uranium bombarded with neutrons, and published the fact while saying plainly that as nuclear physicists they could not bring themselves to explain it. Meitner spent Christmas at Kungälv with her nephew Otto Frisch, and between them they explained it. He had brought skis. She had brought Hahn’s letter.

Then she did the part that mattered. With no table of nuclide masses to six figures, she used the general trend of the mass curve, found that the two fragments together weigh about a fifth of a proton mass less than the nucleus they came from, and converted the difference with Einstein’s exchange rate. About 190 MeV, from a curve and a pencil, in a borrowed house, in exile, with no apparatus. The modern value is near 200 MeV, and Chapter 3 has you repeat the arithmetic.

That is why she is on this volume rather than anyone with a reactor named after them. This book is honest that a reader cannot run a chain reaction on a bench, and about a third of its experiments are therefore calculations, marked as calculations. She is the standing argument that the calculation is the real work.

Hahn took the 1944 Nobel Prize in Chemistry alone. She was nominated forty-eight times across physics and chemistry and never received it. And she refused to work on the bomb, declining the British effort and saying afterwards that she wished she had never been part of the science that made it possible.

About the portrait. The source is a photographic portrait she signed and dated in 1916,, when she was thirty-seven, and it is in the public domain by age. A program converts it to line work, setting each line’s thickness from the local tone of the print. No generative model touched it. The print carries physical damage, and nothing has been painted back in, because a program cannot know what was underneath a scratch: the honest options are to crop or to leave it, and a repair is not one of them.

The rule for this series is that a cover portrait is a document or it is openly a drawing, and it is never a photograph of something that did not happen.

The full account of how this book was made, including which parts were written with the help of a language model, is on the copyright page and on the back cover, itemised using the five credits published at bookcredits.org.

Bench Degree

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