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. 

University of Chicago H9

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University of Chicago H9

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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: 
Graphite blocks
Credit line: 
Argonne National Laboratory, courtesy AIP Emilio Segrè Visual Archives

Graphite blocks. "Photograph shows the 10th layer of graphite blocks which contained pseudospheres of black (U3O8) and brown (UO2) uranium oxide. The brown briquets, slightly richer in uranium, were concentrated in the central area. Visible in the foreground and on either side are cavities filled with graphite, presumed to be an expedient measure dictated by shortage of fuel and, possibly, a last-minute change in the lattice arrangement. 

The entire reactor was assemble within a special balloon-cloth enclosure, part of which is shown in the background. Originally it had been intended to evacuate the air during the experiment to decrease neutron losses and thus make more effective use of the fuel. This proved to be unnecessary so the south side was left open. The completed structure was 57 layers high." 

 The first nuclear reactor was erected in 1942 in the West Stands section of Stagg Field at the University of Chicago.

Original format: 
1 photographic print (black and white; 8.5 x 11 inches)
University of Chicago. Department of Physics