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 2021 so that you may obtain our copies for free. If you cannot wait until 2021, 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.

Havens William F2

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Havens William F2

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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: 
William Havens and Cloud Chamber
Credit line: 
AIP Emilio Segrè Visual Archives

W. W. Havens, Associate Professor of Physics at Columbia University, scans the screen of the cloud chamber, watching the tracks of the nuclear particles. The chamber, set up in the basement of the Pupin Laboratories building at Columbia University, is an apparatus for making visible the paths of sub-microscopic nuclear particles. A cloud is created in the confined volume by the sudden expansion of the air in the chamber, causing a super-saturation of that air with water vapor. When the nuclear particles traverse this cloud, droplets are formed along the paths of the particles due to the ionization of the air molecules. This path is readily photographed with a strong light source and an ordinary camera. The unit into which Professor Havens is peering, is the viewer and the chamber itself. The large section below is the mechanism required to suddenly expand the air in the chamber. All together, the apparatus weighs approximately 300 pounds.

Original format: 
2 photographic prints (black and white; 5 x 7 inches)
Havens, William W. (William Westerfield), 1920-2004