January 16, 2008

432nd Brookhaven Lecture, 1/24

At the Cutting Edge of Bright Beams: The NSLS Source Development Laboratory

Inspired by the myriad of discoveries with synchrotron light at the National Synchrotron Light Source (NSLS) and similar facilities around the world, researchers are always looking for more brilliant beams of light. To develop this next-generation of light sources, the accelerator physicists at the NSLS Source Development Laboratory (SDL) make use of a magnesium photocathode irradiated by ultraviolet laser light to produce electron beams of unprecedented brightness.

Jim Murphy

To learn more about this forefront research, join James Murphy, NSLS Deputy Chairman for Accelerators & Operations, at 4 p.m. on Thursday, January 24 in Berkner Hall as he gives the 432nd Brookhaven Lecture, titled “At the Cutting Edge of Bright Beams: The NSLS Source Development Laboratory.” All are welcome to this free lecture, open to the public. Note that the lecture is on a Thursday, not the usual Wednesday. Visitors to the Lab ages 16 and older must carry a photo ID.

As Murphy will describe in his talk, he and fellow researchers have developed various techniques to catch molecules and atoms in action. In one recent study, the researchers used a laser to control the pulse duration of light from a free-electron laser (FEL), a type of light source with a potential peak brightness up to one billion times higher than that of ordinary synchrotron light. In another technique, Murphy and colleagues generated extremely short pulses of terahertz radiation that are the highest intensity of their type ever produced. Using this light, researchers can “kick” molecular processes such as catalysis or electronic switching (important for developing data storage media) into action and watch their mechanisms on a very short timescale. The intense sub-picosecond electron beams at the SDL are also being advanced to serve directly as a probe of materials in future ultrafast diffraction experiments (UED).

James Murphy earned his Ph.D. in physics from Dartmouth College in 1982. He joined the Accelerator Physics Group at the NSLS in August 1983 as a postdoc to work on FELs and laser acceleration schemes. As a tenured staff member at the NSLS he has pursued his interests in the physics of high brightness electron beams for the development of new synchrotron light sources and FELs.

Beginning in December 2001 as NSLS Associate Chair for Accelerators, Jim led the accelerator team in the preliminary design of the NSLS-II storage ring through the important CD-0 milestone in FY05. Together with a team of dedicated NSLS colleagues, Jim has expanded the SDL into a world-class facility for laser-seeded FEL and high brightness beam research and development. Presently, as the Deputy Chairman for Accelerators & Operations, Murphy is in charge of development of the NSLS storage ring complex and the vibrant research program at the SDL.

To lunch with the lecturer at an off-site restaurant on Friday, January 25, please contact Kathleen Loverro, Ext. 7188.

ARTICLE BY: Kendra Snyder