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The Tevatron collider run 2 Prospects for discoveries in particle physics (open access)

The Tevatron collider run 2 Prospects for discoveries in particle physics

The chances of discovering the Standard Model Higgs boson in Run 2 at the Fermilab Tevatron Collider are discussed. The reach of a search for MSSM Higgs boson and for other Susy particles is also mentioned. The large integrated luminosity potentially offered by the upgraded Tevatron in the years before the start of LHC will make an exciting physics program possible in the next several years. Let aside the luminosity, we can rely now on two much more powerful detectors than in run 1. This is a very real point of strength of the run 2 Tevatron program. The progress of the Tevatron from spring this year has been slow but steady. From this, there is no reason for being pessimistic, but admittedly no particular reason for being optimistic as well. CDF will be able to produce physics quality data early in 2002. After that, data will flow for years and years. We expect to be able to publish the first papers based on the new data in fall 2002.
Date: March 12, 2002
Creator: Bellettini, Giorgio
System: The UNT Digital Library
Generalization of Spatial Channel Theory to Three-Dimensional x-y-z Transport Computations (open access)

Generalization of Spatial Channel Theory to Three-Dimensional x-y-z Transport Computations

Spatial channel theory, initially introduced in 1977 by M. L. Williams and colleagues at ORNL, is a powerful tool for shield design optimization. It focuses on so called ''contributon'' flux and current of particles (a fraction of the total of neutrons, photons, etc.) which contribute directly or through their progeny to a pre-specified response, such as a detector reading, dose rate, reaction rate, etc., at certain locations of interest. Particles that do not contribute directly or indirectly to the pre-specified response, such as particles that are absorbed or leak out, are ignored. Contributon fluxes and currents are computed based on combined forward and adjoint transport solutions. The initial concepts were considerably improved by Abu-Shumays, Selva, and Shure by introducing steam functions and response flow functions. Plots of such functions provide both qualitative and quantitative information on dominant particle flow paths and identify locations within a shield configuration that are important in contributing to the response of interest. Previous work was restricted to two dimensional (2-D) x-y rectangular and r-z cylindrical geometries. This paper generalizes previous work to three-dimensional x-y-z geometry, since it is now practical to solve realistic 3-D problems with multidimensional transport programs. As in previous work, new analytic …
Date: March 12, 2002
Creator: Abu-Shumays, I. K.; Hunter, M. A.; Martz, R. L. & Risner, J. M.
System: The UNT Digital Library
A time dependent fractional coverage model for the adsorption and removal of gas species and application to the friction behavior of superlow friction DLC. (open access)

A time dependent fractional coverage model for the adsorption and removal of gas species and application to the friction behavior of superlow friction DLC.

The frictional behavior of diamond-like carbon (DLC) films varies with environmental condition. One theory asserts that the cause of variations in the frictional performance is environmental contaminants adsorbing onto the DLC film surface. Testing of the frictional performance of DLC films in a pin-on-disk contact has mapped the transient behavior of the friction coefficient. A model for fractional coverage, based on the adsorption of environmental contaminants and their removal through the pin contact, is developed. The rate of adsorption is taken from Langmuir's model [1], which is combined with the removal rate from Blanchet and Sawyer [2]. The coefficient of friction is based on the average fractional coverage under the pin contact. The model also gives a closed-form expression for the steady-state fractional coverage. Model calculations compared favorably to the time progression of the friction coefficient for a series of earlier experiments on a superlow friction DLC coating [3], when the fractional removal term was allowed to increase with increasing sliding speed.
Date: March 12, 2002
Creator: Frysz, P. L.; Sawyer, W. G. & Erdemir, A.
System: The UNT Digital Library
The D0 detector at the Fermilab tevatron in run 2 (open access)

The D0 detector at the Fermilab tevatron in run 2

The D0 (DZERO) Detector at Fermilab has been collecting data since March 1, 2001. The detector has undergone an extensive upgrade to participate in the Run 2 data taking. The design of the detector meets the requirements of the high luminosity environment provided by the accelerator. This paper describes the upgraded detector subsystems and gives an outline of the physics potentials associated with the upgrade.
Date: March 12, 2002
Creator: Parashar, Neeti
System: The UNT Digital Library
The Effect of dead-timeless silicon strip readout at CDF II (open access)

The Effect of dead-timeless silicon strip readout at CDF II

The Run IIa CDF Silicon Upgrade has recently finished installation. The detector uses revision D of the SVX3 readout IC. This final revision incorporated new features in order to improve the potential of dead-timeless operation. This paper describes measurements of dead-timeless effects on silicon strip readout on the test bench. This paper also describes tests of the dynamic pedestal subtraction circuitry, which is shown to improve greatly the dead-timeless performance of the silicon systems.
Date: March 12, 2002
Creator: al., A. Affolder et
System: The UNT Digital Library