Students fill summer days with intensive X-ray and neutron school

ARGONNE, Ill. (Sept. 2, 2005) — Each year as many as 200 students in Ph.D. programs compete to attend Argonne's National School on Neutron and X-ray Scattering. For the talented 60 selected to attend the school here each August, it means two weeks of 10-12 hours a day, six days a week.

The school is in its seventh year. Argonne is the only national laboratory with both types of facilities: the Intense Pulsed Neutron Source (IPNS) for neutron scattering and the Advanced Photon Source (APS) for X-ray scattering.

"The school's philosophy is to provide young scientists studying for their Ph.D. with a general background in available neutron and X-ray techniques," said Dean Haeffner, a physicist and group leader in the Experimental Facilities Division of the APS. Haeffner and physicist Raymond Osborn of the Materials Science Division organized the school this year.

The National School on Neutron and X-Ray Scattering brings the field's top senior scientists from academia, industry and national laboratories together with the brightest young scientists attending U.S. universities. Students attend lectures in the morning and afternoon to establish a basic understanding of a broad range of techniques. Afternoon and evenings are devoted to hands-on experiments and analysis.

The research students are all interested in the behavior of the samples they are studying. X-rays and neutrons provide insight into the atomic and electronic structure of materials and allow researchers to see how materials work at the most basic level and how they can possibly be manipulated to enhance valuable characteristics.

Originally, mostly materials scientists and condensed matter physicists attended. Over the years the class has become more diverse as chemists, biologists, geologists, chemical engineers and soil scientists now participate.

Lectures range from the basics of "Interaction of X-rays and Neutrons with Matter" and X-ray and neutron generation and detection, to more specific topics such as imaging, magnetic scattering, single-crystal diffraction and inelastic X-ray scattering.

Students spend afternoons and evenings with instrument scientists at the two facilities. More than a dozen beamlines and instruments are made available and about three times as many instrument staff contribute their time. These expert instrument scientists work with groups of five students at a time to teach the basics of the experimental instrument's capabilities and then turn the instrument over to the students. The instrument scientists, many of whom developed and oversaw the building of the instruments, are available to the students into the late evening hours.

During the course, students perform four experiments – two each at the APS and IPNS. The teams make presentations of their findings on the last day of class.

"Generally, we use a typical experiment," Haeffner explained, "that we have done before so that we know it works. Often, students will start with a simple experiment and move on to a more challenging one. The idea is to establish a basic framework over a broad range of techniques for the students to consider in their narrow areas of research."

Richard Kelley, a student in organic chemistry at Northwestern University, has performed some small-angle scattering research before, but he wants "to know the theory and the fundamental understanding of the techniques to be able to get the most information out of my data." Plus, he wants to take what he has learned back to his research program into miniature solar cells and share it with his colleagues.

"Any number cruncher can fit the data, but I want to know the method derived from first principles and apply it," Kelley said.

Michelle Morcos, a chemical engineering student at University of California, San Diego, said, "I attended the school in order to learn about as many of the neutron and X-ray scattering techniques as possible. The school is also an opportunity to work with great scientists in your field. Everyone can talk to the instructors and instrument scientists, and they tell students what other techniques they could use to learn more specifically what they want." For example, Morcos wants to study her material's structure and luminescence, and APS has the only instrument available to study both properties simultaneously.

The instrument training is valuable as she already has a research proposal accepted at the APS and has applied for another one. Soon, Morcos will be back at Argonne to run an experiment that will help her study the thermodynamics of semiconductor nanoparticles, also known as quantum dots. These materials may one day change the computing industry.

The hands-on training is a strong advantage. Previously, students mainly learned and specialized in the one technique in which their advisor was expert. But as more synchrotrons and neutron sources are built, and existing ones are made more efficient through the use of automation and improved detectors, more research time is available outside traditional research areas.

"The school is really an entry point for many new possible users," said Haeffner. "It is a way to reach out to young researchers and teach them about the techniques, how to use them and how to use them in their research problems.

"We see lots of former students – more than 100 – return as users, and Argonne has employed several," Haeffner said.

The National School on Neutron and X-ray Scattering is funded by the U.S. Department of Energy's (DOE'S) Office of Basic Energy Sciences in the Office of Science. Lecturers and instrument scientists volunteer their time.

The school is a collaboration of several Argonne divisions: Experimental Facilities, Intense Pulsed Neutron Source, Materials Science and Educational Programs. Division of Educational Programs (DEP) Director Harold Myron said, "The school is another example of outstanding cooperation between DEP and Argonne's research divisions to meet the workforce development needs of DOE and the nation. This synergy will serve the nation well in the future." — Evelyn Brown