Behind the cover: July 2022
Each month, Physics Today editors explore the research and design choices that inspired the latest cover of the magazine.
Two of the feature articles appearing in Physics Today‘s July 2022 issue inspired ideas for the cover. One , by Martin Singh and Morgan O’Neill, explains how Earth’s climate can be understood as a giant heat engine. The other , by Anne Heavey, describes the immense challenges faced by neutrino scientists attempting to build ever-larger detectors.
The systems in both articles lend themselves to dramatic visuals because of their enormous sizes. The swirling air and water that are central to Earth’s atmospheric dynamics form clouds and storms that would have made for striking cover images. And because neutrinos are so elusive—interacting with matter so weakly and infrequently that they pass through most objects unperturbed—detectors must be as large as possible to maximize the number of particles that may produce a measurable signal as they travel through.
In the end, Physics Today‘s senior graphic designer, Freddie Pagani, chose a picture from the Deep Underground Neutrino Experiment for the cover. The larger of the two detectors for DUNE, the experiment featured in Heavey’s article, will hold 70 kilotons of liquid argon. When the experiment’s detectors are finally completed, DUNE will be the world’s largest cryogenic particle detector. The experiment is tasked with tracking neutrino oscillations over a distance of 1300 km; researchers will study how the composition of a neutrino beam produced and characterized at Fermilab in Batavia, Illinois, has changed by the time it reaches Sanford Lab in Lead, South Dakota.
DUNE’s facilities are still very much a work in progress. Excavators of the mine in which the larger detector will sit have faced challenges clearing out the cavern, whose volume is about that of 100 Olympic-size swimming pools. In the meantime, the collaboration’s researchers are testing their technical plans with prototype detectors at CERN. One of those prototypes is featured on the July cover; the fact that it’s just 1/20th the size of the planned detector gives a sense of the experiment’s true scale.
Large research facilities like CERN typically devote resources to producing press-quality images of their experiments, so Pagani had plenty of options to choose from. Her first pick—a photo of a person standing inside one of the DUNE prototype detectors—was a clear winner. The detector’s interior, which fills much of the image, appears to be a shiny gold color because of special lights used to protect the photosensitive instrumentation. And as Physics Today‘s editor-in-chief, Richard Fitzgerald, noted, it’s been some time since a person has appeared on the magazine’s cover. Together, those factors made for an easy consensus on the July issue’s cover image.