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Thank you for the details. There really is so much at play here not even bringing in the spying. I've had a question maybe you would know ever since finishing

by pests 3y ago

Thank you for the details. There really is so much at play here not even bringing in the spying. I've had a question maybe you would know ever since finishing the Rhodes book relating to the initiator. Maybe its a sign of the times the book was written, or maybe purposfully leaving details out, but I had some confusion. At one point its talks about the gun-style design and how it needed to be a certain size in order to accelerate the bullet up to enough speed so that it does not become critical before the bullet makes complete contact with the target. There was what felt like an entire chapter to speccing out the gun and how fast the bullet would need to travel etc. Then later it talks about needing to design a foil initiator which would provide an additional source of neurtons to set it off, which would be sandwiched between the bullet and target. Then what was the worry about the gun size / bullet speed? This was seperate from the initiator that was needed for the implosion type bomb and what I presume Fuchs helped with. I am almost positive this is what I read but the book I feel is unclear or states different things at different times about this topic. Its 1200+ pages and I haven't gone back to look, but just wondering if anyone knows the details here. Did the gun-type bomb need an additional initator or was just shooting the two parts together enough?

defrost 3y ago
I'm getting kind of old, forty years ago I was across much of this and collaborated on a book about some physics of this nature after interviewing Oliphant. The crux of many of the issues with either design was getting a sufficiently high number of neutrons being created within a dense enough source of further neutrons to ensure a full (as full as possible) fission reaction of all the fissile material. Not quickly enough, or with too few neutrons and a "damp squib" would result - a fission reaction that starts, expands, and blows apart the source material with far less than the desired "full fission" release. A fully symmetric spherical implosion compressing inwards all about a sub critical sphere (perhaps formed by bring halves together earlier) was one approach, another was rapidly bring together an excess and to compress a richer source | generator of neutrons for the extra boost to be sure. There's more on that here: https://www.osti.gov/opennet/manhattan-project-history/Science/BombDesign/initiators.html https://www.osti.gov/opennet/manhattan-project-history/Scien... https://www.osti.gov/opennet/manhattan-project-history/Science/BombDesign/gun-type.html https://www.osti.gov/opennet/manhattan-project-history/Scien... and I'm more or less loathe to go on beyond what I can readily find online - although I doubt I can add much beyond what is on public record, I ultimately spent much of my career detecting radiation, environmental and weapons by products, rather than creating bursts of energy.

by pests 3y ago

defrost 3y ago

I'm getting kind of old, forty years ago I was across much of this and collaborated on a book about some physics of this nature after interviewing Oliphant. The crux of many of the issues with either design was getting a sufficiently high number of neutrons being created within a dense enough source of further neutrons to ensure a full (as full as possible) fission reaction of all the fissile material. Not quickly enough, or with too few neutrons and a "damp squib" would result - a fission reaction that starts, expands, and blows apart the source material with far less than the desired "full fission" release. A fully symmetric spherical implosion compressing inwards all about a sub critical sphere (perhaps formed by bring halves together earlier) was one approach, another was rapidly bring together an excess and to compress a richer source | generator of neutrons for the extra boost to be sure. There's more on that here: https://www.osti.gov/opennet/manhattan-project-history/Science/BombDesign/initiators.html https://www.osti.gov/opennet/manhattan-project-history/Scien... https://www.osti.gov/opennet/manhattan-project-history/Science/BombDesign/gun-type.html https://www.osti.gov/opennet/manhattan-project-history/Scien... and I'm more or less loathe to go on beyond what I can readily find online - although I doubt I can add much beyond what is on public record, I ultimately spent much of my career detecting radiation, environmental and weapons by products, rather than creating bursts of energy.