About ALPHA

       Professors S. Y. Lee and Paul Sokol are currently leading the design effort of a multipurpose electron accelerator which will be operated under a joint collaboration between Crane Naval Surface Warfare Center and the Center for the Exploration of Energy and Matter (CEEM). This accelerator will serve the Department of Defense's requirements for testing radiation effects, as well as IU's interest in a compact high-brightness x-ray source. ALPHA will be composed of two parts: 1) an injector capable of producing electron energies of up to 60 MeV and 2) a 20 m electron storage ring. The dipole magnets that will be used in the storage ring were previously used in the Cooler Injector Synchrotron (CIS) at CEEM.

      One of the primary requirements for Crane's radiation effects testing program is the uniformity of the electron radiation dose. It is necessary that the electron beam bunch does not have a frequency dependence in the (1-10 GHz) range since this would interfere with existing Crane diagnostics. In order to overcome this difficulty, the storage ring has been designed to produce a highly uniform electron pulse with a pulse length of up to 50 ns.

      When operating as an X-ray source, the storage ring will form electron bunches approximately 10 ps in length that will collide with a laser pulse with approximately ~ 1 micron wavelength (near infrared-visible range). The collision between the electron beam and the laser beam will produce photons through the Inverse Compton Scattering process, with energies far greater than the laser beam. For a 50 MeV beam, it is possible to produce photon wavelengths ~ 0.03 nm (hard X-ray).

      ALPHA will serve as a user facility for the IU community in a variety of scientific research areas. X-ray and VUV sources are of great importance to the scientific community for probing the structure and properties of biological and condensed matter systems. Small labs that conduct research in these areas typically utilize a rotating anode, which is a compact X-ray source. One of the drawbacks of the rotating anode is that it has a relatively low X-ray flux, which ultimately limits the quality of experiments that can be conducted. One of the great advantages of ALPHA is that it is possible to produce X-ray fluxes which are a factor of 10,000 times greater than the rotating anode.

      The ALPHA accelerator will be an exciting new component to CEEM which will jointly serve the needs of the Navy and the IU community.