RIBSS

Instruments

Designing and building instruments to be used at RIB accelerator laboratories is a key element of the Center. To date, the Center has built an array of silicon detectors for charged particle detection (ORRUBA), an array of plastic scintillator bars for neutron detection (VANDLE), and an array of LaBr3 crystals for γ-ray detection, (HAGRiD). ORRUBA can be coupled to HAGRiD, the Hybrid Array of Gamma Ray Detectors, or Gammasphere for particle-γ coincidence in reaction measurements. VANDLE is used for both decay and reaction measurements and can be coupled to HAGRiD, or other γ-ray detectors to characterize the state populated. HAGRiD has also been used with the Jet Experiments in Nuclear Spectroscopy for Astrophysics (JENSA) gas jet target.

ORRUBA

The Oak Ridge Rutgers Barrel Array (ORRUBA) is a silicon detector array designed for the measurement of protons from (d,p) reactions in inverse kinematics. ORRUBA is comprised of both resistive-strip and non-resistive-strip silicon detectors, arranged in a barrel-like configuration around the target. In 2015, ORRUBA was augmented with new annular detector arrays of graduated silicon strip QQQ5 detectors for measurements at the most backward and forward angles.

ORRUBA is sufficiently compact to be coupled to high efficiency γ arrays for the coincident measurement of charged particles and photons in direct reaction experiments. Gammasphere-ORRUBA: Dual Detectors for Experimental Structure Studies (GODDESS) was commissioned in Summer 2015.

VANDLE

The Versatile Array of Neutron Detectors at Low Energy (VANDLE) was developed to measure both β-delayed and reaction neutrons. VANDLE consists of hundreds of bars, between 0.6 and 2 meters long, with photomultiplier tubes at both ends. The VANDLE data acquisition is based on PIXIE-16 digital pulse processing spectrometers.

VANDLE has been used in various configurations at many different laboratories, often simulataneously in two or more experiments, including at the HRIBF, NSCL, CERN/ISOLDE, and ATLAS/CARIBU for β-delayed neutron studies, and HRIBF, Notre Dame, and NSCL for reaction experiments.

HAGRiD

In 2012, our collaboration proposed to build a high-efficiency, highly flexible, γ-ray array to be used in both decay and reaction experiments in conjunction with charged-particle or neutron detection. This resulted in the Hybrid Array of Gamma Ray Detectors (HAGRiD). Lanthanum bromide (LaBr3(Ce)) was chosen for its relatively good energy resolution (< 3% at 662 keV), high intrinsic efficiency (˜35% at 1 MeV), and good timing resolution (˜200 ps).

The HAGRiD array is comprised of 27 2" x 2", and 10 3" x 3" crystals coupled to Hamamatsu R6231-100 photomultiplier tubes.