0 Se p 20 02 The Dynamical Parameters of the Universe
The results of different analyses of the dynamical parameters of the Universe are converging towards agreement. Remaining disagreements reflect systematic errors coming either from the observations or from differences in the methods of analysis. Compiling the most precise parameter values with our estimates of such systematic errors added, we find the following best values: the baryonic density parameter Ω b h 2 = 0.019 ± 0.02, the density parameter of the matter component Ω m = 0.29 ± 0.06, the density parameter of the cosmological constant Ω λ = 0.71 ± 0.07, the spectral index of scalar fluctuations n s = 1.02 ± 0.08, the equation of state of the cosmological constant w λ < −0.86, and the deceleration parameter q 0 = −0.56 ± 0.04. We do not modify the published best values of the Hubble parameter H 0 = 0.73 ± 0.07 and the total density parameter Ω 0 +0.03 −0.02 .
A Cosmological Model
(I) IT is familiar that the Einstein equations for the density and pressure in a uniform universe: do not suffice to specify the model since there are two equations and three unknown functions, ρ, p and R. A very common assumption is p = 0, but models involving both positive and negative values of p have also been proposed. McCrea1 pointed out that there is no objection in principle to negative pressure and that the steady-state universe can be interpreted in this way.
Proposed beam diagnostics instrumentation for the LANSCE refurbishment project
Presently, the Los Alamos National Laboratory is in the process of planning a refurbishment of various subsystems within its Los Alamos Neutron Science Center accelerator facility. A part of this LANSCE facility refurbishment will include some replacement of and improvement to existing older beam-diagnostics instrumentation. While plans are still being discussed, some instrumentation that is under improvement or replacement consideration are beam phase and position measurements within the 805-MHz side-coupled cavity linac, slow wire profile measurements, typically known as wire scanners, and possibly additional installation of fast ionization-chamber loss monitors. This paper will briefly describe the requirements for these beam measurements, what we have done thus far to answer these requirements, and some of the technical issues related to the implementation of the instrumentation.