Low-Lying Neutron-Hole Transitions in the 207-Pb(p,p') Reaction at 135 MeV

This work was supported by National Science Foundation Grant PHY 75-00289 and Indiana Universit

Transitions to Proton States in the 90-Zr(p,p') Reaction at 160 MeV

This work was supported by National Science Foundation Grant PHY 76-84033 and Indiana Universit

Spin-Orbit Effects on the Shapes of Cross Sections in the 90-Zr(p,p') Reaction at 160 MeV

This work was supported by National Science Foundation Grants PHY 76-84033A01, PHY 78-22774, and Indiana Universit

Excitation of Neutron, Proton and Neutron-Hole States in the (p,p') Reaction at 160 MeV and 96 MeV

This work was supported by National Science Foundation Grant PHY 76-84033 and Indiana Universit

Core Polarization Amplitudes for Single-Neutron-Hole Transitions Excited in the 207-Pb(p,p') Reaction at 135 MeV and 61 MeV

This work was supported by National Science Foundation Grants PHY 76-84033A01, PHY 78-22774, and Indiana Universit

Low-Lying Transitions in the 207-Pb(p,p') Reaction at 135 MeV and a Test of the DWIA

This work was supported by National Science Foundation Grant PHY 76-84033 and Indiana Universit

Studies of the Heavy Transitional Nuclei using the (p,p') Reactions at 135 MeV

This research was sponsored by the National Science Foundation Grant NSF PHY 87-1440

Globally Anisotropic High Porosity Silica Aerogels

We discuss two methods by which high porosity silica aerogels can be engineered to exhibit global anisotropy. First, anisotropy can be introduced with axial strain. In addition, intrinsic anisotropy can result during growth and drying stages and, suitably controlled, it can be correlated with preferential radial shrinkage in cylindrical samples. We have performed small angle X-ray scattering (SAXS) to characterize these two types of anisotropy. We show that global anisotropy originating from either strain or shrinkage leads to optical birefringence and that optical cross-polarization studies are a useful characterization of the uniformity of the imposed global anisotropy.Comment: 18 pages, 14 figures, submitted to Journal of Non-Crystalline Solid

Spin-Orbit Effects in the Excitation of Proton and Neutron States in the (p,p') Reaction at 160 MeV, 120 MeV, and 95 MeV

Supported by the National Science Foundation and Indiana Universit

Pulse Shape Discrimination Techniques in Scintillating CsI(Tl) Crystals

There are recent interests with CsI(Tl) scintillating crystals for Dark Matter experiments. The key merit is the capability to differentiate nuclear recoil (nr) signatures from the background $\beta / \gamma$-events due to ambient radioactivity on the basis of their different pulse shapes. One of the major experimental challenges is to perform such pulse shape analysis in the statistics-limited domain where the light output is close to the detection threshold. Using data derived from measurements with low energy $\gamma$'s and nuclear recoils due to neutron elastic scatterings, it was verified that the pulse shapes between $\beta / \gamma$-events are different. Several methods of pulse shape discrimination are studied, and their relative merits are compared. Full digitization of the pulse shapes is crucial to achieve good discrimination. Advanced software techniques with mean time, neural network and likelihood ratios give rise to satisfactory performance, and are superior to the conventional Double Charge method commonly applied at higher energies. Pulse shape discrimination becomes effective starting at a light yield of about 20 photo-electrons. This corresponds to a detection threshold of about 5 keV electron-equivalence energy, or 40$-$50 keV recoil kinetic energy, in realistic experiments.Comment: 20 pages, 7 figure