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High-speed cameras with ~1 millisecond resolution existed before the Manhattan…

Brief

High-speed camera systems were integral to design and testing of WWII atomic weapons: 1 ms cameras sufficed for U-235 gun-method experiments, but plutonium implosion required ≈10 ns timing, leading to Professor Mack’s 10^-7 s rotating-mirror streak camera (1944) with Berlyn Brixner, which the post credits for enabling Trinity/Fat Man implosion design.

Why it matters

High-speed cameras with ~1 millisecond resolution existed before the Manhattan Project and were adequate for U-235 "gun method" experiments, matching uranium-235’s cited critical insertion time of about 1 ms (e.g., filming bullets leaving gun barrels).

Key details

  • Plutonium implosion tests required much faster photography because of spontaneous fission from Pu-240; the post claims a plutonium critical insertion time of ≈10 nanoseconds, prompting replacement of rotating-drum cameras by Professor Mack’s rotating-mirror (Mack) streak camera in 1944 with 10^-7 s resolution.
  • The Mack streak camera, with assistance from Berlyn Brixner, is credited with enabling the design and perfection of the plutonium cylindrical implosion used at the Trinity test and in the Fat Man bomb — summarized by the claim "No camera, no bomb."
Source evidence

High Speed Electronics

Not many people realise, but the high speed camera systems that filmed the dawn of the atomic age was actually integral to both the observer and the subject.

What does that mean?

Before Manhattan project, high speed cameras existed that could capture 1ms resolution.

This was enough to record the experimental data that would eventually be used to design and construct an atomic bomb.

High speed cameras could video bullets leaving gun barrels, so the optical and camera needs for the U-235 “gun method” experiments were easily met due to uranium 235’s “slow” critical insertion time of about 1 millisecond.

However, a much faster photographic process was required for plutonium experiments because it is spontaneously fissionable due to its plutonium 240 isotope content.

As a result, plutonium has a very fast critical insertion time of approximately 10 nanoseconds.

A rotating drum camera was initially used to conduct implosion studies to design and construct an atomic bomb using plutonium.

However, this camera was replaced in 1944 by a much faster rotating mirror camera with 10^-7 second resolution invented by Professor Mack.

The Mack Streak Camera assisted in the design and perfection of a plutonium cylindrical implosion process with the assistance of Berlyn Brixner. Think about it.

This was the process used in the Trinity test and in the Fat Man bomb dropped on Nagasaki.

No camera, no bomb.

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