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Charge-exchange reactions at intermediate energies have been used extensively in nuclear structure studies as a sensitive probe of the spin-isospin response of nuclei. Experimental investigations have been mostly limited to stable targets. There are, however, compelling scientific arguments to extend these studies to unstable nuclei. The Low Energy Neutron Detection Array (LENDA) is designed to facilitate the study of (p, n) charge exchange reactions in inverse kinematics using unstable beams. The array, which is designed to measure neutron energies and angles with high detection efficiencies, is currently under development at the National Superconducting Cyclotron Laboratory (NSCL). The final array will consist of 24 plastic scintillator bars each with dimensions of 300 x 45 x 25 mm. The neutron energy will be determined by the time-of-flight technique, while the position of interaction will be deduced using the timing and energy information from photomultipliers attached to both ends of each bar. A prototype of the final array has been constructed and characterized in a simple test setup. Results of test measurements and simulations have demonstrated a neutron energy threshold of Index Terms--Nuclear physics, neutron detectors, neutron spectroscopy detectors, neutrons.

Abstract: Cs2LiYCl6 (CLYC) has generated recent interest as a thermal neutron detector due to its excellent pulse-shape discrimination and energy resolution. Here, the capabilities of CLYC as a fast neutron detector and spectrometer are reported. A 1in.×1in. CLYC detector was used to measure the response of mono-energetic neutrons over a range of 0.8–2.0MeV produced via the 7Li(p,n) reaction at the University of Massachusetts Lowell 5.5MV Van de Graaff accelerator. A broad continuum from the 6Li(n, ) reaction was observed, as well as additional peaks below the thermal capture peak. Based on possible reactions in CLYC, the additional peaks are determined to be due to the 35Cl(n,p)35S reaction, with a Q-value of +615keV, and corroborated in simulations using MCNPX. The average resolution of 9% for these peaks makes CLYC a promising candidate for a fast neutron spectrometer. [Copyright &y& Elsevier]

Fast-rotating N = 151 isotones 245 Pu, 247 Cm and 249 Cf have been studied through inelastic excitation and transfer reactions with radioactive targets. While all have a ground-state band built on a ν j 15 / 2 [ 734 ] 9 / 2 − Nilsson configuration, new excited bands have also been observed in each isotone. These odd- N excited bands allow a comparison of the alignment behavior for two different configurations, where the ν j 15 / 2 alignment is either blocked or allowed. The effect of higher order deformations is explored through cranking calculations, which help clarify the elusive nature of ν j 15 / 2 alignments. [ABSTRACT FROM AUTHOR]

Abstract: A 71Ga(3He, t)71Ge charge-exchange experiment was performed to extract with high precision the Gamow–Teller (GT) transition strengths to the three lowest-lying states in 71Ge, i.e., the ground state , the 175 keV and the 500 keV excited states. These are the relevant states, which are populated via a charged-current reaction induced by neutrinos from reactor-produced 51Cr and 37Ar sources. A precise measurement of the GT transition strengths is an important input into the calibration of the SAGE and GALLEX solar neutrino detectors and addresses a long-standing discrepancy between the measured and evaluated capture rates from the 51Cr and 37Ar neutrino calibration sources, which has recently spawned new ideas about unconventional neutrino properties. [Copyright &y& Elsevier]

Abstract: First experimental evidence for a high-spin isomer () in 97Cd, a waiting point in the astrophysical rapid proton capture process, is presented. The data were obtained in β-decay studies at NSCL using the new RF Fragment Separator system and detecting β-delayed protons and β-delayed γ rays. Decays from ground and isomeric states were disentangled, and proton emission branches were determined for the first time. We find half-lives of 1.10(8) s and 3.8(2) s, and β-delayed proton emission branches of 12(2)% and 25(4)% were deduced for the ground and isomeric states, respectively. With these results, the nuclear data needed to determine an rp-process contribution to the unknown origin of solar 96Ru are in place. When the new data are included in astrophysical rp-process calculations, one finds that an rp-process origin of 96Ru is unlikely. [Copyright &y& Elsevier]