Evans Hayward facts for kids

Evans Hayward (born February 17, 1922 – died March 2, 2020) was an important American physicist. She was a top expert in a field called photonuclear physics. This field uses special beams of tiny particles like electrons, positrons, and neutrons from powerful machines called accelerators to study the inside of atomic nuclei. For over 50 years, her research focused on how light (photons) interacts with atomic nuclei. She studied things like how many neutrons are produced when light hits a nucleus, how light scatters off different shapes of nuclei, and how electrons interact with nuclei.

Early Life and Education

Evans Hayward was born on February 17, 1922, in Camp Dix, New Jersey. She loved physics and graduated from Smith College in 1942 with a Bachelor of Arts degree in physics, earning high honors. She then continued her studies at the University of California, Berkeley, where she earned her Master of Science degree in 1945 and her PhD in 1947.

After finishing her education, Evans worked at the National Institute of Standards and Technology (NIST) from 1950 to 1990. She was also awarded a special Guggenheim Fellowship, which helps scientists do important research. Her work included measuring how atoms absorb light and studying magnetic properties.

Career and Discoveries

Evans's early research for her PhD looked at how high-energy particles from space (cosmic rays) created ionization, which is like making an electric charge. She used a special tool called a cloud chamber for these studies. After her PhD, she continued her work at the University of California at Berkeley from 1947 to 1950. There, she used cloud chambers to study particles produced by powerful machines called synchrotrons and cyclotrons. She also measured how protons scattered when hit by neutrons, finding that the scattering wasn't perfectly even.

Working at the National Bureau of Standards

In 1950, Evans and her future husband, Raymond Hayward, both started working at the National Bureau of Standards (NBS), which is now called NIST. Her first experiments there involved using gamma rays and a machine called a betatron. When NBS moved to a new location in Gaithersburg, Maryland, a more powerful machine called a 150 MeV linac became available. This allowed her to do more complex experiments because the electron beam was much stronger.

One of her first projects at NBS was with John Hubbell. They measured how 1-MeV photons (a type of light) reflected off different materials like water, aluminum, and lead. They even used a desk calculator to do complex math that confirmed their experiments!

Exploring Light and Nuclei

Evans then worked with William Dodge on experiments using the linac. They tested ideas about how light interacts with atomic nuclei. One very clever idea was developed by Arenhoevel and Hayward, explaining how polarized photons (light waves vibrating in a single direction) scatter off the "giant resonances" of nuclei. Evans, along with Barber and Sazama, did experiments to test this. They created a special beam of polarized photons and then scattered them off different elements like gold and tin. This was a difficult but important way to study how nuclei behave at specific light energies.

Evans shared an office for many years with her friend and fellow scientist, Mike Danos. They found it very helpful to work together, with the experimentalist (Evans) and the theorist (Mike) sharing ideas daily. One of Evans's important discoveries, which Mike Danos had predicted, was about the "giant resonance" in nuclei that are shaped like ellipsoids (like a stretched ball). She showed that these nuclei had two different energy peaks, depending on their shape, which matched Mike's theories.

Sharing Scientific Knowledge

Evans also continued the important work of her colleague, Everett Fuller, who was an expert in collecting information about photonuclear reactions. When Fuller retired, Evans made sure this valuable collection of data was available to scientists around the world. It's now used by major nuclear data centers in Moscow, Brookhaven National Laboratory, and Vienna. This information became a digital database called the "Photonuclear Data Index." Evans also contributed to this database by making many measurements of photonuclear cross sections herself. Her collaborations with other scientists, like Wolynec, Martins, and Dodge, led to well-known publications in the field.

A Leader in Science

Evans retired from NBS/NIST in 1990, but she continued to work with scientists globally. She always made sure to dress professionally, believing it helped her focus on her experiments. Evans was a woman physicist at a time when very few women were in this field. She knew she had to be excellent to be recognized, and she certainly was! Even though she faced some challenges because of her gender, her colleagues and bosses recognized her amazing achievements.

She was a natural leader and became the Group Leader for the Nuclear Research Group in 1975. She also served as the Deputy Chief of the Nuclear Radiation Division from 1978 to 1980. Evans traveled widely, participating in experiments at powerful accelerators and giving lectures at universities. She was a Guggenheim Fellow in Copenhagen, a Guest Professor in Germany, a Sir Thomas Lyle Fellow in Australia, a Visiting Professor in Canada, a Guest Professor in Germany, and a Senior Visiting Scientist in England. She also held visiting and adjunct professor positions at Duke University and the University of Lund.

Awards and Later Life

In the 1970s, Evans also became involved in many important committees. President Richard Nixon chose her to serve on a special committee for the Atomic Energy Commission. She also helped review applications for Fulbright Scholarships in physics, which help students study abroad. Additionally, she was a member of Maryland Governor Mandel’s Science Advisory Council, which advised the governor on scientific issues.

Evans received many awards for her contributions. She was given the Department of Commerce Silver Medal in 1958 and the Gold Medal in 1971. She also received the Federal Women’s Award in 1975 and the NBS Samuel Wesley Stratton Award in 1980. In 1987, she was selected as an NBS Fellow, and in 1995, her portrait was added to the NIST Portrait Gallery of Distinguished Scientists, Engineers and Administrators. She was also a Fellow of the American Physical Society, a very respected group of physicists.

Even after fully retiring, Evans continued to learn! She took evening classes at American University in subjects like politics, international relations, Spanish, and Italian. When asked why, she simply said she still wanted to learn. Evans was preceded in death by her husband, Ray, and their two sons. Scientists from all over the world have shared their sadness at her passing and their appreciation for her support and encouragement in their research.

Death

Evans Hayward passed away on March 2, 2020, in Chevy Chase, Maryland, due to heart disease.