11B and Constraints on Neutrino Oscillations and Spectra from Neutrino Nucleosynthesis

We have studied the sensitivity to variations in the triple alpha and 12C(alpha, gamma)16O reaction rates, of the yield of the neutrino process isotopes 7Li,11B, 19F, 138La, and 180Ta in core collapse supernovae. Compared to solar abundances, less than 15% of 7Li, about 25-80% of 19F, and about half of 138La is produced in these stars. Over a range of two sigma for each helium-burning rate, 11B is overproduced and the yield varies by an amount larger than the variation caused by the effects of neutrino oscillations. The total 11B yield, however, may eventually provide constraints on supernova neutrino spectra

On the Sensitivity of Massive Star Nucleosynthesis and Evolution to Solar Abundances and to Uncertainties in Helium Burning Reaction Rates

We explore the dependence of pre-supernova evolution and supernova nucleosynthesis yields on the uncertainties in helium burning reaction rates. Using the revised solar abundances of Lodders (2003) for the initial stellar composition, instead of those of Anders & Grevesse (1989), changes the supernova yields and limits the constraints that those yields place on the 12C(a,g)16O reaction rate. The production factors of medium-weight elements (A = 16-40) were found to be in reasonable agreement with observed solar ratios within the current experimental uncertainties in the triple alpha reaction rate. Simultaneous variations by the same amount in both reaction rates or in either of them separately, however, can induce significant changes in the central 12C abundance at core carbon ignition and in the mass of the supernova remnant. It therefore remains important to have experimental determinations of the helium burning rates so that their ratio and absolute values are known with an accuracy of 10% or better.Comment: Accepted for publication by the Astrophysical Journa

OGO-E space vehicle response to transient loading at Atlas booster engine cutoff

Computer program for OGO-E vehicle response analysis to transient loading during Atlas booster burnou

Polarization mode dispersion in radio-frequency interferometric embedded fiber-optic sensors

The effect of fiber birefringence on the propagation delay in an embedded fiber-optic strain sensor is studied. The polarization characteristics of the sensor are described in terms of polarization mode dispersion through the principal states of polarization and their differential group delay. Using these descriptors, an analytical expression for the response of the sensor for an arbitrary input state of polarization is given and experimentally verified. It is found that the differential group delay, as well as the input and output principal states of polarization, vary when the embedded fiber is strained, leading to fluctuations in the sensor output. The use of high birefringence fibers and different embedding geometries is examined as a means for reducing the polarization dependency of the sensor

Representation of second-order polarisation mode dispersion

A new expansion for the Jones matrix of a transmission medium is used to describe high-order polarisation dispersion. Each term in the expansion is characterised by a pair of principal states and the corresponding dispersion parameters. With these descriptors, a new expression for pulse deformation is derived and confirmed by simulation