Emilio Segrè Visual Archives

More than 30,000 photos of scientists and their work

Attention ESVA Patrons:

The Emilio Segrè Visual Archives’ site is moving soon and adopting an open access approach to digital image sharing. Once we have transitioned to the new site in 2021, we will no longer charge for our high-resolution digital images or usage fees (note that we do not hold copyright to all the images in our collections and you will still need to obtain permission for those which we do not own).

If you are working on a long-term project, we advise you to wait until the migration is complete so that you may obtain our copies for free. If you cannot wait, email us at nbl [at] aip.org and we will do what we can to assist you. We will not be offering refunds for past purchases.

For more information, please visit our FAQ page on the Ex Libris Universum blog. 

Brookhaven National Laboratory H3

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Brookhaven National Laboratory H3

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We charge a usage fee per photo if the photo is published, reproduced in a product or publicly exhibited. This is not a license in the legal sense. As a non-profit institution, we do not make any money providing these photographs. It is only by assessing usage fees that we are able to cover the cost of providing publication quality copies of our photos, preserving the photograph collection according to archival standards, and providing access to the collection by maintaining an online image database. The copyright holder may charge a fee in addition to our service fee.

Images are for use in educational projects only and must be used in a respectful manner.

Image title: 
Photograph taken in a 20-inch liquid hydrogen bubble chamber of an anti-proton (1) colliding with a proton
Credit line: 
Photo courtesy Brookhaven National Laboratory. For Publication Permission Request contact Jane Koropsak, BNL-Media and Communications, [email protected], Tel: 631-344-4909

Photograph taken in a 20-inch liquid hydrogen bubble chamber of an anti-proton (1) colliding with a proton. The accompanying sketch shows the event with the proper assignment of a particle to each track. At the vertex of the anti-proton track, a collision occurs with the stationary proton in the liquid hydrogen. Track 2 is that of a positive pi-meson, while track 3 is identified as a cascade hyperon, which decays into other particles (tracks 9, 4, 5, and 6). The third product of the initial anti-proton collision is the anti-Xi-zero particle; since it has no electrical charge it leaves no track, but its direction of travel is shown in 10. This particle then decays into an anti-lambda-zero (11), and a neutral pi-meson (12), which also leave no tracks. The subsequent decay products of the anti-lambda particle, however, do leave tracks (7 and 8). From these decay products, and other phenomena, the preceding chain of events can be deduced, making it possible for the first time to identify the production of the rare anti-Zi-zero particle.

Photo date: 
circa 1963
Original format: 
2 photographic prints (black and white; 9 x 7.5 inches and 8 x 7 inches)
Brookhaven National Laboratory