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Silicon detector readout system using commercially available items

Description: The basic properties of silicon detectors are briefly noted, including bulk and electrical properties. Thermal and shot noise in front end amplifiers is discussed. The configuration of detectors and preamps is then briefly described. A detector test is described and results are given. (LEW)
Date: May 1, 1986
Creator: Green, D.
Partner: UNT Libraries Government Documents Department

/bar p/p collider physics

Description: This note encompasses a set of six lectures given at the summer school held at Campos Do Jordao in January of 1989 near Sao Paulo, Brazil. The intent of the lectures was to describe the physics of /bar p/p at CERN and Fermilab. Particular attention has been paid to making a self contained presentation to a prospective audience of graduate students. Since large Monte Carlo codes might not be available to all members of this audience, great reliance was placed on ''back of the envelope estimates.'' Emphasis was also placed on experimental data rather than theoretical speculation, since predictions for, for example, supersymmetric particle production are easily obtained by transcription of formulae already obtained. 9 refs., 67 figs., 2 tabs.
Date: March 1, 1989
Creator: Green, D.
Partner: UNT Libraries Government Documents Department

Tables of thermodynamic functions for gaseous thorium, uranium, and plutonium oxides

Description: Measured and estimated spectroscopic data for thorium, uranium, and plutonium oxide vapor species have been used with the methods of statistical mechanics to calculate thermodynamic functions. Some inconsistencies between spectroscopic data and some thermodynamic data have been resolved by recalculating ..delta..H/sup 0//sub f/ (298.15/sup 0/K) values for the vapor species of these oxides. Evaluation of the uncertainties in data, methods of estimating molecular parameters, and effects of assumptions have been discussed elsewhere. The tables of thermodynamic functions that were reported earlier have been revised principally because the low-frequency vibrational modes of UO/sub 2/ and UO/sub 3/ have now been measured. These new empirical data resulted in changes in the electronic contributions to the calculated thermodynamic functions of UO/sub 2/ and the estimated vibrational contributions for PuO/sub 2/. In addition, some minor changes have been made in the methods of calculation of the electronic contributions for all molecules.
Date: March 1, 1980
Creator: Green, D.W.
Partner: UNT Libraries Government Documents Department

Experimental electro-thermal method for nondestructively testing welds in stainless steel pipes

Description: Welds in austenitic stainless steel pipes are notoriously difficult to nondestructively examine using conventional ultrasonic and eddy current methods. Survace irregularities and microscopic variations in magnetic permeability cause false eddy current signal variations. Ultrasonic methods have been developed which use computer processing of the data to overcome some of the problems. Electro-thermal nondestructive testing shows promise for detecting flaws that are difficult to detect using other NDT methods. Results of a project completed to develop and demonstrate the potential of an electro-thermal method for nondestructively testing stainless steel pipe welds are presented. Electro-thermal NDT uses a brief pulse of electrical current injected into the pipe. Defects at any depth within the weld cause small differences in surface electrical current distribution. These cause short-lived transient temperature differences on the pipe's surface that are mapped using an infrared scanning camera. Localized microstructural differences and normal surface roughness in the welds have little effect on the surface temperatures.
Date: January 19, 1979
Creator: Green, D. R.
Partner: UNT Libraries Government Documents Department

Vapor pressures and vapor compositions in equilibrium with hypostoichiometric uranium dioxide at high temperatures

Description: Thermodynamic functions of the gaseous species, thermodynamic functions of the condensed phase, and an oxygen-potential model have been combined to calculate the vapor pressures and vapor compositions in equilibrium with condensed-phase UO/sub 2-x/ for 1500 less than or equal to T less than or equal to 6000 K and 0 less than or equal to x less than or equal to 0.5. A method for extending the oxygen-potential model of Blackburn to the liquid region has been derived and evaluated. New thermodynamic functions of the UO/sub 2/ condensed phase have been derived from the best available data, including the heat capacity recommended by Fink.
Date: June 1, 1981
Creator: Green, D.W. & Leibowitz, L.
Partner: UNT Libraries Government Documents Department

Feasibility study on infrared electro-thermal NDE of stainless steel

Description: Electro-thermal examination, a branch of thermal testing (TT), is a promising method being developed for NDE of stainless steel welds. This report describes the first phase of development; i.e., preliminary demonstration and laboratory evaluation of the method's sensitivity to notches in Type 304 stainless steel plate specimens. It also includes a description of the basic principles, together with a description of the hardware and experimental results showing that electrical discharge machined notches down to 0.16 cm (0.06 in.) long x 0.08 cm (0.03 in.) deep were detected. A qualitative technique for interpreting the test results to determine whether defects are at the surface or deeper within the material is demonstrated. (auth)
Date: November 1, 1975
Creator: Green, D.R. & Hassberger, J.A.
Partner: UNT Libraries Government Documents Department

Development of a method for evaluating carbon dioxide miscible flooding prospects. Final report

Description: Research was undertaken to develop a method of evaluating reservoirs as prospects for carbon dioxide flooding. Evaluation was to be based on a determination of miscibility pressure and displacement efficiency under idealized conditions. To reach the objective, project work was divided into five areas: (1) conducting of phase-equilibrium studies of carbon dioxide with synthetic oils; (2) application of an equation of state to simulate the phase behavior of carbon dioxide - oil systems; (3) conducting of linear displacements of crude oils and synthetic oils by carbon dioxide in a slim-tube apparatus; (4) application of the equation of state, the phase-behavior data and slim-tube data to develop a method of screening reservoirs for carbon dioxide flooding based on determination of minimum miscibility pressure and displacement efficiency; (5) development of a one-dimensional mathematical model, based on the equation of state, for application in conjunction with the results of Parts 1 to 4. The accomplishments for these five areas are discussed in five chapters. 44 references, 90 figures, 42 tables.
Date: March 1, 1985
Creator: Green, D.W. & Swift, G.W.
Partner: UNT Libraries Government Documents Department

Simple model of calorimeter sampling response in a magnetic field

Description: The fact that plastic scintillator ``brightens`` in the presence of a magnetic field has been known for some time. Recently, measurements have been extended to larger field strengths ( < 20 T ) and a saturation of the effect was observed for fields > 2.5 T. Thus the active element in a sampling calorimeter may be expected to have a signal increase of {approx} 6-8 % when immersed in fields of strength > 2.5 T. This brightening of the scintillator is independent of the orientation of the field. In addition to these effects, there has been reported an increase in the signal seen by sampling calorimeters due to incident electrons in the presence of a magnetic field. In contrast to the brightening effect, there does not appear to be saturation at the field strengths used (B < 2.5 T) and the magnitude of the effect appears to be somewhat larger than that expected from brightening alone, {approx}20% at 2.5 T. A comprehensive program has been mounted to study these problems in the context of CMS calorimetry and new results are expected momentarily. In particular, field strengths up to 3 T are employed, and field orientations parallel and perpendicular to the incident particle are to be explored.
Date: October 1, 1996
Creator: Green, D.
Partner: UNT Libraries Government Documents Department

Hadron calorimeter performance with a PbWO4 EM compartment

Description: The CMS detector[1] at the LHC has chosen PbWO4 in order to achieve the superior photon energy resolution which is crucial in searching for the 2 photon decay of low mass Higgs bosons. The hadronic compartment is thought to be Cu absorber, since one is immersed in a 4 T magnetic field, read out by scintillator tiles coupled to wavelength shifter (WLS) fibers. The combined performance of this calorimeter is of interest in the study of jets and missing transverse energy (neutrino, SUSY signatures). For this reason, a test was made of the electromagnetic (EM) compartment combined with a reasonable approximation to the baseline HCAL ``barrel`` calorimeter. Data was taken in the H4 CERN beamline. The EM compartment was a 7 {times} 7 square array of PbWO4 crystals, which for the purposes of this study are considered as a single readout in depth (or ``compartment``) [2]. The HCAL module consisted of large scintillator plates with 24 individual longitudinal readout channels. The EM compartment was followed by 10 Cu plates each 3 cm thick, followed by 9 Cu plates each 6 cm thick. This set of absorber plates represented the HCAL compartments inside the coil. The coil itself [1] was approximated as Al and Fe plates, of a total thickness of about 1.4 absorption lengths. The coil mockup was sampled and then followed by 4 plates of 8 cm thick Cu, each with an individual readout which represented a test of the ``Tailcatcher`` concept.
Date: January 1996
Creator: Green, D.
Partner: UNT Libraries Government Documents Department

Uniformity requirements in CMS hadron calorimetry

Description: Practical considerations of calorimeter systems require a specification of the allowed manufacturing tolerances. The tightness of these requirements directly makes an impact on the assembly costs of the calorimeter. For that reason, a precise and well defined set of criteria is mandatory. In addition, the intrinsic limitations of hadron calorimetry define the level of accuracy needed in the manufacture of such devices. Therefore, considerations of the limitations on energy measurement accuracy due to Physics should define the needed level of effort to produce a uniform calorimetric device.
Date: February 1, 1996
Creator: Green, D.
Partner: UNT Libraries Government Documents Department

Effect of dead material in a calorimeter

Description: The existence of dead material in any practical calorimeter system is simply a fact of life. The task for the designer, then, is to understand the impact on the Physics in question, and strive to minimize it. The aim of this note is to use the ``Hanging File`` test data, which has fined grained individual readout of about 100 depth segments, to explore impact of dead material on the mean and r.m.s. of the hadronic distribution. The amount and location of the dead material is varied. It important to remember that the Hanging File data was calibrated, EM to HCAL compartment, so as to minimize the electron to pion energy dependence. In practical terms e/pie was made = 1.0 at an incident energy of about 100 GeV. Note that the PB(EM) + FE(HCAL) calorimeter was not a compensating device.
Date: October 1, 1995
Creator: Green, D.
Partner: UNT Libraries Government Documents Department

Physics requirements for LHC/SSC calorimetry

Description: The goal of the next generation of collider detectors is to study the origin of electroweak symmetry breaking. The mass scale for this study is roughly 1 TeV. No matter what the details of the mechanism, one can be confident that new phenomena will occur, since weak interactions become strong, i.e., violate partial wave unitarity, at that mass scale. The partial wave amplitude for ee{yields} WW scattering is; ao{approximately}4{phi}/{alpha}{sub w}(M{sub w}/M){sup 2}, ao{approximately}1 if M {approximately}1 TeV. Therefore, the detectors for LHC/SSC must be able to confront this mass scale. In particular, the electroweak dynamics is such that the study of gauge boson pairs has a high priority. Given that the simplest decay modes for gauge boson are into leptons, the new detectors will naturally tend to optimize performance for leptons.
Date: October 1, 1991
Creator: Green, D.
Partner: UNT Libraries Government Documents Department

Dijet mass resolution and compensating calorimetry

Description: The calorimetry for SSC detectors has as its role the detection of the basic particles of the Standard Model. Those germane to calorimetry are quarks, photons, electrons, and gluons. Note that all the hadronic entities appear in the calorimetry as jets. The detection of single hadrons belongs to a past era when quark molecules'' were the focus of intense study. Thus, the goal of calorimetry at the SSC must be the study of jets. In particular, one must understand what defines the limits of accuracy of the jets. If there are intrinsic physical processes which limit the precision of jet measurements, then calorimetry which is more accurate is unnecessary if not wasteful. 5 refs., 5 figs.
Date: May 1, 1991
Creator: Green, D.
Partner: UNT Libraries Government Documents Department

Effect of inert material on ZZ mass resolution for H yields ZZ yields eeee

Description: A detector with a modest sized magnetic field volume will, of necessity, have inert material (solenoid coil) in front of the calorimetry. It is therefore crucial to assess the impact of that material on the physics of interest. Since the thickness of material is of order a radiation length, Xo, and only a fraction of a nuclear interaction length, the physics topics concern the EM calorimetry. In this note, a Higgs boson with a wide variety of masses is used as a paradigm of SSC physics. Low mass Higgs bosons approximate the kinematics of inclusive Z production, while high mass Higgs bosons probe the extremes of phase space to be explored at the SSC. The scale of interest is the natural width of the Z, since backgrounds will increase should the resolution due to the inert material exceed this basic scale. 4 refs., 3 figs.
Date: April 1, 1991
Creator: Green, D.
Partner: UNT Libraries Government Documents Department

Infrared NDT methods applied to solar cell and panel characterization

Description: Infrared nondestructive testing (NDT) methods are described that have a good potential for providing valuable data concerning solar cell or panel characteristics without requiring contact with the photovoltaic device. Preliminary tests with cells and panels were conducted and the infrared NDT results are presented and discussed. (MHR)
Date: October 20, 1978
Creator: Green, D. R. & Olsen, L. C.
Partner: UNT Libraries Government Documents Department

Improving reservoir conformance using gelled polymer systems. Annual report, September 25, 1994--September 24, 1995

Description: The objectives of the research program are to (1) identify and develop polymer systems which have potential to improve reservoir conformance of fluid displacement processes, (2) determine the performance of these systems in bulk and in porous media, and (3) develop methods to predict their performance in field applications. The research focused on four types of gel systems -- KUSP1 systems which contain an aqueous polysaccharide designated KUSP1, phenolic-aldehyde systems composed of resorcinol and formaldehyde, colloidal-dispersion systems composed of polyacrylamide and aluminum citrate, and a chromium-based system where polyacrylamide is crosslinked by chromium(III). Gelation behavior of the resorcinol-formaldehyde systems and the KUSP1-borate system was examined. Size distributions of aggregates that form in the polyacrylamide-aluminum colloidal-dispersion gel system were determined. Permeabilities to brine of several rock materials were significantly reduced by gel treatments using the KUSP1 polymer-ester (monoethylphthalate) system, the KUSP1 polymer-boric acid system, and the sulfomethylated resorcinol-formaldehyde system. The KUSP1 polymer-ester system and the sulfomethylated resorcinol-formaldehyde system were also shown to significantly reduce the permeability to super-critical carbon dioxide. A mathematical model was developed to simulate the behavior of a chromium redox-polyacrylamide gel system that is injected through a wellbore into a multi-layer reservoir in which crossflow between layers is allowed. The model describes gelation kinetics and filtration of pre-gel aggregates in the reservoir. Studies using the model demonstrated the effect filtration of gel aggregates has on the placement of gel systems in layered reservoirs.
Date: May 1, 1996
Creator: Green, D.W. & Willhite, G.P.
Partner: UNT Libraries Government Documents Department

Electron optics in hybrid photodetectors in magnetic fields

Description: The CMS detector design has the hadronic calorimeter immersed in a 4 T magnetic field. The scintillator photon transducer must work reliably in this environment. The baseline phototransducer is the ``hybrid photomultiplier``, which consists of a standard photocathode (S20) followed by a high field acceleration onto the surface of a Si diode. Such a device has a linear response, 1 e out for every 3.6 eV of potential drop in excess of the threshold needed to penetrate the passivation layer of the diode. A threshold voltage of {approximately}2 kV is typical of these devices, leading to a gain of {approximately}2000 at 10 kV applied voltage. In the interest of reducing costs, the Si surface can be cut into pixels. However, the optics of the electron trajectories must be well understood so as to avoid crosstalk between pixels caused by misalignment of the accelerating electric field and the axis of the CMS magnetic field. The depletion depth of the Si is quite standard, {approximately}300 {mu}m. The source capacity is {approximately}20 pF. The output pulse has a {approximately}6 nsec risetime for > 60 V diode biasing. The device is expected to be highly immune to magnetic field effects due to the short spacing, {approximately}3 mm, between photocathode and Si.
Date: December 1, 1996
Creator: Green, D.
Partner: UNT Libraries Government Documents Department

Improving reservoir conformance using gelled polymer systems. Quarterly technical progress report, July 1, 1995--September 30, 1995

Description: Objectives of this project are to identify and develop gelled polymer systems which have potential to improve reservoir conformance to fluid displacement systems; determine the performance of these systems; and to develop methods to predict the capability of these systems to recover oil from petroleum reservoirs. Gels investigated include an aqueous polysaccharide, a chromium-polacrylamide, and an aluminium citrate-polyacrylamide system.
Date: October 17, 1995
Creator: Green, D.W. & Willhite, G.P.
Partner: UNT Libraries Government Documents Department