A facility for studying radiative capture reactions induced with radioactive beams at ISAC (original) (raw)
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Design of a New Recoil Separator for Measurements of Radiative Capture Reactions in Astrophysics
2010
The rates of proton-and alpha-capture reactions on unstable proton-rich nuclei are needed to understand the energy generation and element synthesis occurring in novae, X-ray bursts, and other explosions. Direct measurements of the cross sections of some of these reactions are now possible with radioactive beams and a recoil separator. A new device for such measurements, the Separator for CApture Reactions [SECAR], is being designed for use at the Facility for Rare Isotope Beams (FRIB). The specifications and preliminary conceptual design will be discussed along with plans for the first set of measurements.
A recoil separator for the measurement of radiative capture reactions
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1996
A recoil separator in combination with a windowless gas target has been designed for the measurement of the radiative capture reaction p('Be, y)'B. The separator consists of momentum and velocity filters and a A&E detector telescope. The setup was tested quantitatively using the p("C, y)"N reaction at the effective energy E,, = 841 keV. Projectile fluxes were measured directly with Faraday cups and indirectly with elastic backscattering into Si detectors, while the "N recoil flux was measured directly with the A.!-E telescope. A suppression of the "C beam particles by a factor 2 X IO-"' was observed when the system was tuned for the recoil "N's, Special emphasis was given to the charge state probabilities of the llN recoils.,Possible improvements of the system for the measurement of other capture reactions are discussed. @'('Be) = I pnA = 6 X 10' s-') from the 'B recoils
GLORIA: A compact detector system for studying heavy ion reactions using radioactive beams
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2014
The GLObal ReactIon Array (GLORIA) has been designed in order to study direct nuclear reactions induced by exotic nuclei at energies close to the Coulomb barrier. The detector array consists of six silicon particle-telescopes arranged in a very close geometry around a 30 • rotated-target system, allowing the measurement of reaction fragments in a continuous angular range from 15 • to 165 • (Lab.). GLORIA has been used for the first time at the SPIRAL/GANIL facility at Caen (France) to study the scattering of the system 8 He+ 208 Pb at the collision energies of 16 and 22 MeV.
Measuring Difficult Reaction Rates Involving Radioactive Beams: A New Approach
Proceedings of International Symposium on Nuclear Astrophysics - Nuclei in the Cosmos - IX — PoS(NIC-IX), 2010
Rates of sub-barrier, radiative capture reactions involving radioactive reactants, needed for understanding various astrophysical explosive scenarios, are often quite difficult to measure directly at relevant stellar temperatures. In general relatively intense radioactive beams (>10 11 /s) are needed for these inverse kinematic studies, as cross sections are very low. A new production approach is described herein that would supply such required intensities in a relatively straightforward fashion. While this system may have many applications, one area could be increasing our understanding of classical novae and X-ray bursts.
Recoil separators for radiative capture using radioactive ion beams
The European Physical Journal A, 2014
Radiative capture reactions involving the fusion of hydrogen or helium are ubiquitous in the stellar history of the universe, and are some of the most important reactions in the processes that govern nucleosynthesis and energy generation in both static and explosive scenarios. However, radiative capture reactions pose some of the most difficult experimental challenges due to extremely small cross sections. With the advent of recoil separators and techniques in inverse kinematics, it is now possible to measure radiative capture reactions on very short-lived radioactive nuclei, and in the presence of high experimental backgrounds. In this paper we review the experimental needs for making measurements of astrophysical importance on radiative capture reactions. We also review some of the important historical advances in the field of recoil separators as well as describe current techniques and performance milestones, including descriptions of some of the separators most recently working at radioactive ion beam facilities, such as DRAGON at TRIUMF and the DRS at the Holifield Radioactive Ion Beam Facility. We will also summarize some of the scientific highlight measurements at the RIB facilities.
SECAR: A recoil separator for nuclear astrophysics
EPJ Web of Conferences, 2022
Proton-and alpha-capture reactions on unstable proton-rich nuclei power astrophysical explosions like novae and X-ray bursts. Direct measurements of these reactions are crucial for understanding the mechanisms behind these explosions and the nucleosynthesis at such sites. The recoil mass separator, SECAR (SEparator for CApture Reactions) at the National Superconducting Cyclotron Laboratory (NSCL) and the Facility for Rare Isotope Beams (FRIB), has been designed with the required sensitivity to study (p,γ) and (α,γ) reactions, directly at astrophysical energies in inverse kinematics, with radioactive beams of masses up to about A = 65. The complete SECAR system, including two Wien Filters for high mass resolution, has been installed at Michigan State University and is currently being commissioned. The present article introduces the SECAR concept, its scientific goals, and provides an update of the current status of the project.
Performance of the ARES recoil separator for (p,γ) reaction measurements
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2003
In Louvain-la-Neuve, the Astrophysics REcoil Separator (ARES), was installed to measure ðp; gÞ reactions of astrophysical interest induced by radioactive beams. ARES was coupled to the CYCLONE44 cyclotron. First tests performed with an 19 F stable beam, i.e., the Hð 19 F; 20 NeÞg reaction, are reported. r
Feasibility of low-energy radiative-capture experiments at the LUNA underground accelerator facility
The European Physical Journal A, 2005
The LUNA (Laboratory Underground for Nuclear Astrophysics) facility has been designed to study nuclear reactions of astrophysical interest. It is located deep underground in the Gran Sasso National Laboratory, Italy. Two electrostatic accelerators, with 50 and 400 kV maximum voltage, in combination with solid and gas target setups allowed to measure the total cross sections of the radiative capture reactions 2 H(p,γ) 3 He and 14 N(p,γ) 15 O within their relevant Gamow peaks. We report on the gamma background in the Gran Sasso laboratory measured by germanium and bismuth germanate detectors, with and without an incident proton beam. A method to localize the sources of beam induced background using the Doppler shift of emitted gamma rays is presented. The feasibility of radiative capture studies at energies of astrophysical interest is discussed for several experimental scenarios.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2000
The recently commissioned Recoil Mass Spectrometer (RMS) at the Holi"eld Radioactive Ion Beam Facility (HRIBF) is described. Consisting of a momentum separator followed by an E-D-E Rochester-type mass spectrometer, the RMS is the centerpiece of the nuclear structure endstation at the HRIBF. Designed to transport ions with rigidities near K"100, the RMS has acceptances of 1010% in energy and 104.9% in mass-to-charge ratio. Recent experimental results are used 0168-9002/00/$ -see front matter
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2007
A detector has been designed and built to assist in-beam gray spectroscopy with fusion-evaporation reactions. It measures with high efficiency the evaporation residues that recoil out of a thin target into the angular interval from 1.81 to 9.01 at an adjustable distance of 1000-1350 mm from a target, in coincidence with grays detected in a Ge-detector array. This permits filtering of such grays out of a much stronger background of other reaction products and scattered beam. Evaporation residues are identified by their time-of-flight and the pulse height using a pulsed beam. The velocity vector of the g-emitting recoil is also measured in the event-by-event mode, facilitating to correct the registered gray energy for the Doppler shift, with the resulting significant improvement of the energy resolution. The heavy-ion detection scheme uses emission of secondary electrons caused by the recoiling ions when hitting a thin foil. These electrons are then electrostatically accelerated and focused onto a small scintillator that measures the summed electron energy, which is proportional to the number of electrons. The detector is able to operate at high frequency of the order of 1 MHz and detect very heavy nuclei with as low kinetic energy as 5 MeV. The paper describes the properties of the detector and gives examples of measurements with the OSIRIS, GAREL+ and EUROBALL IV gray spectrometers. The usefulness of the technique for spectroscopic investigations of nuclei with a continuous beam is also discussed.