What is HIGS ?
The High Intensity Gamma-Ray Source is a novel light source with unprecedented photon flux, extemely small beam-related background, and a wide range of precisely tuneable gamma-ray energies. Using a Storage Ring (SR) Free-Electron-Laser (FEL), polarized gamma rays are produced by intra-cavity Compton backscattering FEL-photons from highly-relativistic electrons. Unlike bremsstahlung photon sources where the total flux may be higher, the photon density ( photons / eV) is much higher at HIGS. The tuned energy (signal) to continuous energy (background) flux ratio at HIGS is nearly a million ! Tuneability of the FEL, as well as of the electron momentum, makes it possible to set the energy to an accuracy of a few keV or better. Collimation alone makes it possible to obtain beam energy spreads better than 1%. These unique features make HIGS a very desirable venue to perform a variety of photo-nuclear experiments not possible elsewhere, as well as industrial based applications.
Physics @ HIGS
The HIGS facility is suited for experiments where high flux, large photon density, low beam background, 100% beam polarization and high energy resolutions are a necessity. The nuclear physics experiments have been arranged under flagship programs of nuclear-astrophysics, photo-physics beyond pion threshold, measurements of the Gerasimov-Drell-Hearn (GDH) Sum Rule, Nuclear Resonance Fluorescence (NRF), Few-Body studies, Compton scattering, and Nuclear Spectroscopy / Applications. These programs are detailed in the Nuclear Physics section.
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Success Stories ! Some of the experiments which have been successfully performed and published include near-threshold photodisintegration of the deuteron and indirect measurements of the GDH Sum rule; assignment of Parity to nuclear levels on various nuclei with focus on studies of scissor-mode and two-phonon collective states; measurement of the Compton scattering cross-section analyzing power addressing the existence of the iso-vector giant-quadrapole resonance in Oxygen-16; gamma-ray attenuation coefficients of various targets (undertaken by LANL); and tests of various detectors such as the MEGA detector (a satellite based gamma-ray observatory being jointly developed by NASA and German space agencies)
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Partners in Success The success of the HIGS physics program has been facilitated by the interest, support, and commitment by various institutions including Univ. of Virginia, Univ. of Saskatchewan, George Washington Univ., North Georgia College and State University, Univ. of New Hampshire, Yale Univ., MIT-Bates, Univ. of Connecticut, Los Alamos National Lab., Jefferson Lab., Lawrence Livermore National Lab., and many others.
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Location, Location, Location !
The HIGS facility is a sister laboratory to the Triangle Universities Nuclear Laboratory (TUNL), both located on the Duke West Campus. The physics program at HIGS is managed through the resources of TUNL. All three TUNL partners, Univ. of North Carolina, North Carolina State Univ., and Duke Univ. contribute resources and manpower to the operation of the HIGS program. TUNL, which is reputed for producing outstanding nuclear physicists, having a faculty and staff of global recognition, and for executing a very significant nuclear physics research program is ideally suited for partnership with a laboratory of novel gamma-ray capabilities.
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Today and Tomorrow . . .
As we continue to make ground breaking measurements in gamma-ray physics, our agenda is to complete the goals set forth in our short-term as well as to be prepared for the long-term range of experiments. Our strategy has been to perform, analyze and publish the experiments we can perform today, and plan, propose and prepare for the experiments outlined for the post-upgrade era (see HIGS upgrade) and beyond.
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Funding Sources The nuclear physics research programs at HIGS are funded by grants from the Office of Science of the US Department of Energy (DOE) DE-FG02-97ER41033 (Duke), DE-FG02-03ER41231 (Duke), DE-FG02-97ER41042 (NC-State), and DE-FG02-97ER41041 (UNC). The HIGS Upgrade Project is funded by the grant from the Office of Science, DOE, DE-FG02-01ER41175.
