Experimental Devices at the Fox Laboratory
ANASEN
The Array for Nuclear Astrophysics Studies with Exotic Nuclei "ANASEN" is an active-target detector array developed specifically for experiments with radioactive ion beams. ANASEN is a collaborative project between Louisiana State University (LSU) and Florida State University (FSU). ANASEN is a leading detector system for reactions of astrophysical interest at FSU and also in the re-accelerated beam facility REA-3 of the NSCL.
Scientific Article: 10.1016/j.nima.2017.07.030
Local contact: Dr. Ingo Wiedenhoever
CATRiNA
CATRiNA (Compound Array for Transfer and Resonance Reactions in Nuclear Astrophysics) is a premier neutron-detection array at Fox Lab, utilizing a spread of sixteen liquid scintillator detectors of deuterated benzene attached to photomultiplier tubes.
Scientific Article: 10.1016/j.nima.2019.03.084
Local contact: Dr. Sergio Almaraz-Calderon
CeBrA
The Cerium Bromide Array (CeBrA) demonstrator for particle-γ coincidence experiments at the SE-SPS has recently been commissioned at the John D. Fox Laboratory. It has been extended since with four 3x3 inch detectors on temporary loan from Mississippi State University. This extended demonstrator has a combined full energy peak (FEP) efficiency of about 3.5% at 1.3 MeV. For comparison, the five-detector demonstrator has an FEP efficiency of about 1.5% at 1.3 MeV. Over the next years, a 14-detector array will be built in collaboration with Ursinus College and Ohio University through funding from the U.S. National Science Foundation, combining the existing detectors of the demonstrator with five additional 3x4 inch and four 3x6 inch CeBr3 detectors. The γ rays, detected in coincidence with particles in the SE-SPS focal plane, provide access to important complementary information such as γ-decay branching ratios and particle-γ angular correlations for spin-parity assignments, as well as the possibility to determine nuclear level lifetimes via fast-timing techniques and excluding feeding due selective excitation energy gates with the SE-SPS.
Scientific Article: 10.1016/j.nima.2023.168827
Local contact: Dr. Mark-Christoph Spieker
CLARION2 (+ TRINITY)
CLARION2-TRINITY is a new setup at the John D. Fox Laboratory for high-resolution γ-ray spectroscopy in conjunction with charged particle detection and was installed in collaboration with Oak Ridge National Laboratory. The γ rays are recorded by Clover-type High-Purity Germanium detectors (HPGe) detectors. The geometry is chosen to be non-Archimedian and detectors are arranged such that no detectors have a separation of 180 deg to suppress coincident detection of 511-keV γ rays from pair production. The TRINITY particle detector uses a relatively new type of scintillator, Gadolinium Aluminum Gallium Garnet doped with Cerium (GAGG:Ce). This scintillator has intrinsic particle discrimination capabilities through two decay components with different decay times and varying relative amplitudes. The particle identification with the GAGG:Ce is obtained by comparing waveform integrals of the fast "peak" and the delayed "tail". The ratio of these two quantities allows to discriminate between protons, α particles, and heavier ions. The array was commissioned in December 2021 with nine clover-type HPGe detectors and two rings of GAGG:Ce scintillators. This initial setup has now been augmented with a tenth clover-type HPGe detector and all five GAGG:Ce rings of TRINITY installed. More details on the combined setup including a description of energy-loss and contaminant measurements with the zero-degree GAGG:Ce detector can be found in the scientific article below.
Scientific Article: 10.1016/j.nima.2022.167392
Local contact: Dr. Vandana Tripathi
ENCORE
Encore is a new active target and detector system at the John D. Fox lab at FSU. Encore is a MUlti-Sampling Ionization Chamber (MUSIC) - type detector which is based in energy loss measurements using a segmented anode. It is designed to measure excitation functions of several nuclear reactions with a single beam energy. Encore is portable and can be used with stable as well as with radioactive beams.
Local contact: Dr. Sergio Almaraz-Calderon
RESOLUT
RESOLUT is an in-flight radioactive beam facility, which uses beams from the TANDEM-LINAC to create exotic, radioactive isotopes not found in nature. The isotopes, which are created through a nuclear reaction in the production target, are separated in mass by the combined effect of the electrical fields in the superconducting RF-resonator and the magnetic fields of the spectrograph.
The Beams of radioactive isotopes are created by bombarding a gas cell filled with H2, D2, 3He or 4He. We use single- or double-nucleon transfer or charge-exchange reactions, such as (p,n), (d,n), (d,p) or (3He,n).
The following table describes the parameters of radioactive beams from RESOLUT, which were used in experiments to date. Other beam species or energies are possible, given an intense primary beam from the Tandem-Linac and a production reaction with sufficient cross-section.
| Beam | Production Reaction | Energy [MeV] | Intensity [pps] | Purity [%] |
|---|---|---|---|---|
| 6He | 7Li(d,3He)6He | 18-29 | 1 × 104 | 40 |
| 7Be | 7Li(p,n)7Be | 23-35 | 2 × 105 | 80 |
| 8Li | 7Li(d,p)8Li | 20-30 | 5 × 104 | 90 |
| 8B | 6Li(3He,n)8B | 30-45 | 1 × 104 | 10 |
| 17F | 16O(d,n)17F | 80 | 2 × 105 | 80 |
| 19O | 18O(d,p)19O | 80 | 5 × 104 | 90 |
| 18Ne | 16O(3He,n)18Ne | 70 | 2 × 104 | 25 |
| 25Al | 24Mg(d,n)25Al | 98 | 1 × 104 | 35 |
Local contact: Dr. Ingo Wiedenhoever
RESONEUT
The RESONEUT detector setup was developed for resonance spectroscopy using (d,n) reactions with radioactive beams in inverse kinematics and at energies around the Coulomb barrier. The goal of experiments with this setup is to determine the spectrum and proton-transfer strengths of the low-lying resonances, which have an impact on astrophysical reaction rates. The setup is optimized for proton transfers in inverse kinematics, for which most neutrons are emitted at backward angles with energies in the 80–300 keV range. The detector system is comprised of nine p-terphenyl scintillators as neutron detectors, two annular silicon-strip detectors for light charged particles, one position-resolving gas ionization chamber for heavy ion detection, and a barrel of NaI-detectors for the detection of gamma rays.
Scientific Article: 10.1016/j.nima.2017.09.019
Local contact: Dr. Ingo Wiedenhoever
Split-Pole Spectrograph
The Super-Enge Split-Pole Spectrograph (SE-SPS) has been moved to FSU after the Wright Nuclear Structure Laboratory (WNSL) at Yale University ceased operation and was installed in collaboration with Louisiana State University. Like any spectrograph of the split-pole design, the SE-SPS consists of two pole sections used to momentum-analyze reaction products and focus them at the magnetic focal plane to identify nuclear reactions and excited states. H. Enge specifically designed the SE-SPS spectrograph as a large-acceptance modification to the traditional split-pole design for the WNSL. The increase in solid angle from 2.8 to 12.8 msr was achieved by doubling the pole-gap, making the SE-SPS well-suited for coincidence experiments. At FSU, the SE-SPS was commissioned in 2018. In singles experiments, i.e., stand-alone mode, the SE-SPS with its current light-ion focal plane detection system can be used to study the population of excited states in light-ion induced reactions, determine (differential) cross sections and measure the corresponding angular distributions. Currently, laboratory scattering angles of up to 60 deg can be covered. The focal-plane detector consists of a position-sensitive proportional counter with two anode wires, separated by about 4.3 cm, to measure position, angle, and energy loss, and a large plastic scintillator to determine the rest energy of the residual particles passing through the detector. Under favorable conditions, the detector can be operated at rates as high as two kilocounts/s (kcps). As the position resolution depends on the solid angle, target thickness and beam-spot size, it may vary from experiment to experiment. In standard operation and with a global kinematic correction, i.e., assuming a vertical shift of the real focal plane with respect to the two position-sensitive sections of the detector, a full width at half maximum of 30-70 keV has been routinely achieved. This corresponds to a position resolution of about two millimeters. This resolution can be improved further with position-dependent offline corrections.
Local contact: Dr. Mark-Christoph Spieker