About HEPL


HEPL in a Nutshell

HEPL (WW Hansen Experimental Physics Laboratory) is Stanford's first and oldest independent research laborator. It supports interdisciplinary research programs in fundamental science and engineering. In partnership with other departments and schools (e.g., Engineering and Medicine), HEPL provides unique research and educational opportunities for undergraduate, graduate, and postdoctoral students.

Campus Location of HEPL

HEPL is located in the Physics/Astrophysics (Varian II) building, adjoining the Phsics (VarianI) building between the main Quad and the new Science and Engineering Quad.

Campus Map and directions to HEPL, with locations of frequently used conference/seminar rooms

A Brief History of HEPL

Birth of the WW Hansen Experimental Physics Lab in 1951

The W.W. Hansen Experimental Physics Laboratory (HEPL) began as the High Energy Physics Laboratory (also HEPL) in 1951 (it was renamed in 1990), after the Stanford Microwave Laboratory was split into two divisions, HEPL and the Microwave Laboratory (subsequently renamed Ginzton Laboratory). Prior to 1990, the two laboratories were collectively known as the W.W. Hansen Laboratories of Physics.

The predecessor Microwave Laboratory, occupying the building that is now known as HEPL, began as a division of the Physics Department in 1945. It was there that the world's first high power klystrons were developed by Edward L. Ginzton and Marvin Chodorow, and there, under the leadership of William Webster Hansen, that the world's first electron linear accelerator was built.

The microwave research begun in Physics Department by Hansen with Russell H. Varian and Sigurd F. Varian before World War II had a dual impact on physics and engineering that is evident throughout HEPL's history. As Ginzton modestly put it: "Not only did the microwave art promise new application, but as a new tool, it promised to be helpful in physics research as well." New lines of research originated at HEPL continue to "promise new application" and "promise to be helpful in physics research."

For its first decade, HEPL's operations centered on accelerator research, though following two distinct lines: high resolution electron scattering under Robert Hofstadter and meson physics under Wolfgang K.H. Panofsky. Hofstadter was awarded the 1961 Nobel Prize for his work on nuclear form factors. Panofsky went on to develop the immensely successful two-mile-long accelerator at the Stanford Linear Accelerator Center (SLAC), the successor to HEPL accelerators.

View/Download: The Story of Stanford's Two-Mile Long Accelerator by Douglas Wm. Dupen. May 1966. Technical Report Prepared Under
Contract AT(04-3)-400 for the USAEC, San Francisco Operations Office (PDF Document, 8MB)

Expanding the Scope of HEPL in the 1960s

Starting around 1963, a wide variety of new research programs were based in HEPL.

In accelerator physics the dominating new activity of the Laboratory from 1964 through 1981 was the development of the superconducting accelerator (SCA). The idea of the SCA was simple. It was to operate an accelerator structure at superfluid helium temperatures with resonant cavities made of superconducting niobium instead of copper. Between 1979 and 1981 the SCA demonstrated its capability for doing nuclear physics in several experiments, and even more important, that it had two deeply significant technological offshoots: it provided the way for making the free electron laser (FEL) a success; and it gave HEPL an internationally unique capability in the application of large scale cryogenic technology.

The FEL, invented by John M.J. Madey, is a device that generates intense coherent radiation by the motion of free electrons through a resonant structure. Since its initial development at Stanford, FEL research has become a major international activity. The Stanford FEL, operating at wavelengths between 1.6 and 10 micrometers, began operation in 1976. The FEL is one of the largest current activities in HEPL. It is strongly interdepartmental, involving the collaboration of Electrical Engineering, Physics, Applied Physics, SLAC and Medical School faculty.

HEPL Today

Starting from different sources, a most remarkable group of programs has appeared in HEPL, clustered around a broad theme of space physics, astrophysics, and the use in special ways of large scale cryogenic techniques. These programs are interdepartmental and multi-disciplinary. They involve exciting and planned collaborations with the Aero-Astro and Electrical Engineering departments and overlap significant interests in Applied Physics and Mechanical Engineering. They are at the frontier of physics and technology.

HEPL has been the home of many interesting and remarkable experiments that explore space, time and matter. We look forward to many more exciting projects!