Construction and commissioning of the SuperORRUBA detector Bardayan, D.W.; Ahn, S.; Blackmon, J.C. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2013, Letnik:
711, Številka:
1
Journal Article
Recenzirano
The SuperORRUBA (Oak Ridge Rutgers University Barrel Array) of double-sided silicon strip detectors has been constructed at the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National ...Laboratory (ORNL). The array will primarily be used to study single-nucleon transfer reactions in inverse kinematics at exotic beam facilities. The detector exhibits good intrinsic energy resolution (∼25keV) and large solid-angle coverage over the polar angular range 55–125°. The detector is now in routine use and has been used for several measurements at the HRIBF.
A new gas-filled ionization chamber for high count rate particle identification has been constructed and commissioned at the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National ...Laboratory (ORNL). To enhance the response time of the ionization chamber, a design utilizing a tilted entrance window and tilted electrodes was adopted, which is modified from an original design by Kimura et al. 1. A maximum counting rate of ~700,000~700,000 particles per second has been achieved. The detector has been used for several radioactive beam measurements performed at the HRIBF.
Studies on nuclear astrophysics, nuclear structure, and other interests have been performed using the radioactive-isotope (RI) beams at the low-energy RI beam separator CRIB, operated by Center for ...Nuclear Study (CNS), the University of Tokyo. The elastic resonant scattering is a striking tool to study astrophysical reactions and nuclear clusters. In particular, when it is coupled with a thick target and inverse kinematics, the measurement can be very efficient and even feasible with RI beams. By measuring resonant scattering, we can study the properties of resonant states which could play an important role in the astrophysical reaction, or have an exotic nuclear structure. The 10Be+α elastic scattering has been measured at CRIB, and three resonances which are in agreement with the prediction of a linear-chain structure by Suhara-En'yo were observed, giving a strong indication of the existence of such an exotic structure. Measurements based on the indirect technique of the reaction measurement, such as the Trojan horse method, have also been performed at CRIB.
In the network of reactions present in the Big Bang nucleosynthesis, the 3He(n, p)3H reaction has an important role which impacts the final 7Li abundance. The Trojan Horse Method (THM) has been ...applied to the 3He(d, pt)H reaction in order to extract the astrophysical S(E)-factor of the 3He(n, p)3H reaction in the Gamow energy range. The experiment will be described in the present work together with the first preliminary results.
In-flight fission of a 345MeV per nucleon 238U primary beam on a 2mm thick 9Be target has been used to produce and study the decays of a range of neutron-rich nuclei centred around the doubly ...mid-shell nucleus 170Dy at the RIBF Facility, RIKEN, Japan. The produced secondary fragments of interest were identified event-by-event using the BigRIPS separator. The fragments were implanted into the WAS3ABI position sensitive silicon active stopper which allowed pixelated correlations between implants and their subsequent β-decay. Discrete γ-ray transitions emitted following decays from either metastable states or excited states populated following beta decay were identified using the 84 coaxial high-purity germanium (HPGe) detectors of the EURICA spectrometer, which was complemented by 18 additional cerium-doped lanthanum bromide (LaBr3) fast-timing scintillation detectors from the FATIMA collaboration. This paper presents the internal decay of a metastable isomeric excited state in the odd-odd nucleus 168Tb, which corresponds to a single proton-neutron hole configuration in the valence maximum nucleus 170Dy. These data represent the first information on excited states in this nucleus, which is the most neutron-rich odd-odd isotope of terbium (Z=65) studied to date. Nilsson configurations associated with an axially symmetric, prolate-deformed nucleus are proposed for the 168Tb ground state the observed isomeric state by comparison with Blocked BCS-Nilsson calculations.
•First spectroscopy of excited states in the neutron-rich radioisotope 168Tb.•Decay gamma-rays identified using the EURICA gamma-ray spectrometer at the RIBF facility, RIKEN, Japan.•Blocked BCS pairing Nilsson calculations.
Hydrolysis of plasma arginine to citrulline by arginine deiminase (ADI) was recently shown to suppress lipopolysaccharide-induced nitric oxide (NO) synthesis. Since arginine is the precursor of NO, ...and the latter modulates angiogenesis, we explored whether ADI treatment significantly affected tube-like (capillary) formation of human umbilical vein endothelial cells. Inhibition occurred in a dose-dependent manner, both in the chorioallantoic membrane and the murine Matrigel plug assay. Inhibition of angiogenesis by ADI was reversed when a surplus of exogenous arginine was provided, indicating that its antiangiogenic effect is primarily due to arginine depletion, although other pathways of interference are not entirely excluded. Arginine deiminase is also shown to be as a potent inhibitor of tumour growth in vitro as in vivo, being effective at nanogram quantities per millilitre in CHO and HeLa cells. Thus, it could be highly beneficial in cancer therapy because of its two-pronged attack as both an antiproliferative and an antiangiogenic agent.
In the network of reactions present in the Big Bang nucleosynthesis, the 3He(n, p)3H has an important role which impacts the final 7Li abundance. The Trojan Horse Method (THM) has been applied to the ...3He(d, pt)H reaction in order to extract the astrophysical S(E)-factor of the 3He(n, p)3H in the Gamow energy range. The experiment will be described in the present work together with the first preliminary results.
This contribution will report on the experimental work on the level structure of 168Dy. The experimental data have been taken as part of the EURICA decay spectroscopy campaign at RIBF, RIKEN in ...November 2014. In the experiment, a 238U primary beam is accelerated up to 345 MeV/u with an average intensity of 12 pnA. The nuclei of interest are produced by in-flight fission of 238U impinging on Be target with a thickness of 5 mm. The excited states of 168Dy have been populated through the decay from a newly identified isomeric state and via the β decay from 168Tb. In this contribution, scientific motivations, experimental procedure and some preliminary results for this study are presented.
This short paper presents the identification of a metastable, isomeric-state decay in the neutron-rich odd-odd, prolate-deformed nucleus 166Tb. The nucleus of interest was formed using the in-flight ...fission of a 345 MeV per nucleon 238U primary beam at the RIBF facility, RIKEN, Japan. Gamma-ray transitions decaying from the observed isomeric states in 166Tb were identified using the EURICA gamma-ray spectrometer, positioned at the final focus of the BigRIPS fragments separator. The current work identifies a single discrete gamma-ray transition of energy 119 keV which de-excites an isomeric state in 166Tb with a measured half-life of 3.5(4) μs. The multipolarity assignment for this transition is an electric dipole and is made on the basis internal conversion and decay lifetime arguments. Possible two quasi-particle Nilsson configurations for the initial and final states which are linked by this transition in 166Tb are made on the basis of comparison with Blocked BCS Nilsson calculations, with the predicted ground state configuration for this nucleus arising from the coupling of the v(1-/2)521 and π(3+/2) Nilsson orbitals.
There are a number of astrophysical environments in which the path of nucleosynthesis proceeds through proton-rich nuclei. These nuclei have traditionally not been available as beams, and thus ...proton-capture reactions on these nuclei could only be studied indirectly. At the Holifield Radioactive Ion Beam Facility (HRIBF), some of the first direct measurements of (
p
,
) cross-sections on radioactive beams have been made. The Daresbury Recoil Separator (DRS) has been used to separate the recoils of interest from the unreacted primary beam and identify them in an isobutane-filled ionization counter. First data from
17
F (
p
,
18
Ne and
7
Be (
p
,
8
B measurements are presented.
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