Spectroscopy of 98Ru

The nucleus 98 Ru has been investigated by means of γ - γ coincidence, γ - γ angular correlation and K-internal conversion coefficient measurements. The results have led to spin-parity assignment to several levels and to the determination of E 2/ M 1 mixing ratios for the most intense transitions

Shape transitions far from stability: The nucleus 58Cr

Abstract Excited states up to I π = 8 + in the neutron-rich nucleus 58Cr have been identified by using a new experimental setup composed of the large acceptance magnetic spectrometer PRISMA and the highly efficient γ-detector array CLARA. Interestingly, the excitation energy sequence of the ground-state band follows the one expected by the E ( 5 ) dynamical symmetry for a nucleus at the critical point of the shape phase transition from a spherical vibrator ( U ( 5 ) ) to a γ-soft rotor ( O ( 6 ) ). For the first time, in the same physical system, large scale shell-model calculations in the full fp shell are compared to the E ( 5 ) analytical model results and to the Interacting Boson Model. The theoretical results are in excellent agreement with the present data

Lifetime measurements of excited states in neutron-rich nuclei around 48 Ca

The lifetimes of the first excited states of the N = 30 isotones 50Ca and 51Sc and the Z = 18 isotopes 44−46Ar isotopes have been determined using a novel technique that combines the Recoil Distance Doppler Shift method with the CLARA-PRISMA spectrometers in multinucleon transfer reactions. The results allow determinination of the effective charges above 48Ca and test the strength of the N = 28 magic number when moving away from the stability line.Gadea Raga, Andrés, [email protected] ; Algora, Alejandro, [email protected] ; Rubio Barroso, Berta, [email protected]

Spin-polarized low-energy positron beams and their applications

The production and use of low-energy (100 eV to 5 keV) high-intensity, spin-polarized positron beams is reviewed. Methods for obtaining beams with high polarization are discussed. Applications include studies of the moderation process, surface and bulk magnetism, optically active molecules, and the production of polarized anti-protons.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47033/1/339_2004_Article_BF00635183.pd

Distributed fiber-optic interferometric sensor for the detection of pressure fluctuations in reservoirs

A fiber-optic interferometric sensor for the detection of the resonant modes of reservoirs is reported. Study of the characteristics of fiber-optic hydrophones identified the ratio ΔL/Δp, i.e., the differential fiber-optic elongation due to pressure change, as the critical parameter to be enhanced in order to improve the sensor sensitivity. A model of the sensor, suitable for detecting the very-low-frequency and long-wavelength pressure changes characteristic of reservoir resonances, is proposed. The sensor is designed as a straight length of optical fiber with small masses attached at regular intervals. The dynamical analysis shows a sensitivity two orders of magnitude larger than that of the unmodified optical fiber. Use of the sensor as a resonant device is discussed. Experiments performed using the first prototype in a resonant tank are described and agree well with theoretical predictions, confirming the validity of the approac