The Ejection of Protons from Nitrogen Nuclei, Photographed by the Wilson Method With: On the Design and Use of a Double Camera for Photographing Artificial Disintegrations. PATRICK MAYNARD STEWART BLACKETT.
The Ejection of Protons from Nitrogen Nuclei, Photographed by the Wilson Method With: On the Design and Use of a Double Camera for Photographing Artificial Disintegrations
The Ejection of Protons from Nitrogen Nuclei, Photographed by the Wilson Method With: On the Design and Use of a Double Camera for Photographing Artificial Disintegrations
The Ejection of Protons from Nitrogen Nuclei, Photographed by the Wilson Method With: On the Design and Use of a Double Camera for Photographing Artificial Disintegrations
The Ejection of Protons from Nitrogen Nuclei, Photographed by the Wilson Method With: On the Design and Use of a Double Camera for Photographing Artificial Disintegrations

The Ejection of Protons from Nitrogen Nuclei, Photographed by the Wilson Method With: On the Design and Use of a Double Camera for Photographing Artificial Disintegrations

“[Blackett’s] beautiful result provided unambiguous and visible evidence both for the disintegration and for the synthesis of a heavier atom from a lighter [one], fully confirming Rutherford's expectation that one element can be artificially transmuted into another.” -Luisa Bonolis

OFFPRINTS OF TWO PAPERS BY BLACKETT, INCLUDING HIS FAMOUS PHOTOGRAPHIC PROOF THAT RADIOACTIVITY COULD PRODUCE ALPHA DECAY, AND HIS DISCUSSION OF DUAL-CAMERA CLOUD CHAMBER SET-UPS, TWO PAPERS THAT CONTRIBUTED TO HIS BEING AWARDED THE 1948 NOBEL PRIZE IN PHYSICS.

After completing his undergraduate degree in 1921, Blackett obtained a fellowship that allowed him to remain in Cambridge as a postgraduate student at the Cavendish Laboratory under Rutherford. Rutherford sought to prove that radioactivity could produce artificial nuclear decay, and “[l]ike many of his fellow researchers, was put to work by Rutherford counting the microscopic scintillations that provided evidence of the expulsion of protons from atomic nuclei targeted with fast alpha particles.” (Dictionary of National Biography).

However, because looking at scintillations was inefficient, “Rutherford asked Blackett to become acquainted with and investigate the cloud chamber, a device invented by C. T. R. Wilson, with which tracks of ionising particles could be visualised.” (Bonolis). Doing so, he developed a method to improve the timing of capturing photographs in the cloud chamber. “When the volume of a cloud chamber suddenly expands, the temperature decreases and water droplets form on charged particles in the chamber. Blackett perfected a spring action linking the sudden expansion to a camera shutter so that a photograph is taken just as the expansion is completed.” This improvement permitted Blackett, in 1924 to identify “eight [particle] tracks (from twenty-three thousand photographs) showing the capture of an incident alpha particle by a nitrogen nucleus, creating an isotope of oxygen, and the path of a hydrogen ion (proton) ejected from the recoiling oxygen nucleus.” (Complete Dictionary of Scientific Biography). His results were first published in the 1925 paper offered here, and the photographs he captured “were widely reprinted after that, [making] Blackett’s reputation at the age of twenty-seven.” (ibid).

Blackett would go on to further improve the cloud chamber technique, and in 1929 he provided theoretic considerations and limitations on a double-camera set-up that aimed to improve the number of tracks that could be captured. (The second paper offered here.) This work likely influenced his later work with Occhialini where by connecting a two-camera cloud chamber system to a Geiger counter they were able to capture cosmic rays and the first photographic evidence of the positron. In 1948, Blackett would receive the Nobel Prize in physics "for his development of the Wilson cloud chamber method, and his discoveries therewith in the fields of nuclear physics and cosmic radiation," including both his work with Occhialini and the earlier work reported in the papers offered.

Reference:

Bonolis, Luisa. Research Profile of Patrick Maynard Stuart Blackett. Lindau Nobel Laurent Meetings.

OFFPRINTS from The Proceedings of the Royal Society, A, Vol. 107, 1925. and Vol. 123, 1929. Octavo, original pale green wrappers. Pencil note on front wrapper of 1929 issue, a few smudges to wrappers. Housed together in a custom box.

Price: $1,900 .

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