HIGS . . .

The newest accelerator facility operated by TUNL is the HIGS at the Duke Free Electron Laser Laboratory (DFELL). The DFELL houses an accelerator based photon source in a 52,000 square-foot facility. There are two types of primary photon beams available at the DFELL: the HIGS with energies from 2 to 60 MeV and an optical beam with continuous tunable wavelength from IR to VUV. Both photon beam types are produced by an electron storage ring free electron laser (FEL) and its undulators.

Accelerator Facilities

TUNL operates three accelerator facilities for nuclear physics research. All are located on the campus of Duke University. Two are low-energy charged-particle beam facilities and the other is a high intensity Gamma-ray beam facility. Each facility is described below.

High Intensity Gamma-Ray Source (HIGS)

The newest accelerator facility operated by TUNL is the HIGS at the Duke Free Electron Laser Laboratory (DFELL). The DFELL houses an accelerator based photon source in a 52,000 square-foot facility. There are two types of primary photon beams available at the DFELL: the HIGS with energies from 2 to 60 MeV and an optical beam with continuous tunable wavelength from IR to VUV. Both photon beam types are produced by an electron storage ring free electron laser (FEL) and its undulators. The FEL consists of electromagnetic undulators that are installed in the straight section of the 1.2-GeV racetrack-shaped storage ring. The undulators form the active elements of optical klystron (OK) FELs with a long optical cavity of 53.7 m. A nearly monoenergetic gamma-ray beam is produced by intracavity Compton backscattering of the photons in the optical cavity by the stored electrons. The gamma-ray beam can be produced with either linear or circular polarization with a very high degree of polarization. The specifications of the gamma-ray beam and technical specifications of the storage ring are given below.


Tandem Accelerator Laboratory

The main accelerator is a FN tandem Van de Graaff accelerator that has a maximum terminal voltage of 10 MV. Negative ions can be injected into the tandem from three sources: (1) a direct extraction negative ion source provides pulsed or dc beams of unpolarized H- and D- ions, (2) an atomic beam polarized ion source provides dc beams of polarized H- and D- ions, and (3) a heavy-ion source provides dc beams of helium ions. After acceleration, momentum analyzed beam can be delivered to any one of six beam lines. The main target-room equipment includes two general-purpose charged-particle scattering chambers, a gas-jet target and associated charged-particle scattering chamber, a neutron time-of-flight spectrometer system, and an Enge split-pole magnetic spectrometer. The tandem laboratory also houses the Low-Energy Beam Accelerator Facility (LEBAF) which provides users with polarized and unpolarized beams of protons, deuterons and helium ions from 20 to 680~keV. The LEBAF is located in the low-energy bay of the tandem laboratory with beam lines connected to the analyzing magnet at the output of the polarized ion source. The LEBAF is equipped with a 200-kV mini-tandem accelerator and two scattering chambers, one that can be biased to 200 kV. Beam for LEBAF comes from the atomic beam polarized ion source which outputs polarized and unpolarized beams of H+/- or D+/- ions and beams of helium ions at energies from 20 to 80 keV. The combined use of the mini-tandem and the 200-kV high-voltage scattering chamber extends the upper energy reach of LEBAF to 680 keV.



Laboratory for Experimental Nuclear Astrophysics

The LENA is among only a few accelerator facilities in the world dedicated entirely to nuclear astrophysics experiments. It has two low-energy electrostatic accelerators that are capable of delivering high-current charged-particle beams to a common target. One is an ECR source on a 200-kV platform and the other one is a 1-MV JN Van de Graaff accelerator. Both accelerators are fully computer-controlled and transport ion beams to a common target. LENA is unique in the sense that it will cover the whole energy range below 1~MeV with ion beams of high intensity and stability.



TUNL Main Office Contacts

1 (919) 660 2600



Duke University, Room 416, TUNL Bldg, P. O. Box 90308, Durham, NC 27708-0308, USA
bwest@tunl.duke.edu