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Cellular growth and survival are mediated by beta 1 integrins in normal human breast epithelium but not in breast carcinoma
We previously established a rapid three-dimensional assay for discrimination of normal and malignant human breast epithelial cells using a laminin-rich reconstituted basement membrane. In this assay, normal epithelial cells differentiate into well-organized acinar structures whereas tumor cells fail to recapitulate this process and produce large, disordered colonies. The data suggest that breast acinar morphogenesis and differentiation is regulated by cell-extracellular matrix (ECM) interactions and that these interactions are altered in malignancy. Here, we investigated the role of ECM receptors (integrins) in these processes and report on the expression and function of potential laminin receptors in normal and tumorigenic breast epithelial cells. Immmunocytochemical analysis showed that normal and carcinoma cells in a three-dimensional substratum express profiles of integrins similar to normal and malignant breast tissues in situ. Normal cells express {alpha}1, {alpha}2, {alpha}3, {alpha}6, {beta}1 and {beta}4 integrin subunits, whereas breast carcinoma cells show variable losses, disordered expression, or down regulation of these subunits. Function-blocking experiments using inhibitory antiintegrin subunit antibodies showed a >5-fold inhibition of the formation of acinar structures by normal cells in the presence of either anti-{beta}1 or anti-{alpha}3 antibodies, whereas anti-{alpha}2 or -{alpha}6 had little or no effect. In experiments where collagen type I gels were used instead of basement membrane, acinar morphogenesis was blocked by anti-{beta}1 and -{alpha}2 antibodies but not by anti-{alpha}3. These data suggest a specificity of integrin utilization dependent on the ECM ligands encountered by the cell. The interruption of normal acinar morphogenesis by anti-integrin antibodies was associated with an inhibition of cell growth and induction of apoptosis. Function-blocking antibodies had no inhibitory effect on the rate of tumor cell growth, survival or capacity to form colonies. Thus under our culture conditions breast acinar formation is at least a two-step process involving {beta}1-integrin-dependent cellular growth followed by polarization of the cells into organized ...
Fast Poisson, Fast Helmholtz and fast linear elastostatic solvers on rectangular parallelepipeds
FFT-based fast Poisson and fast Helmholtz solvers on rectangular parallelepipeds for periodic boundary conditions in one-, two and three space dimensions can also be used to solve Dirichlet and Neumann boundary value problems. For non-zero boundary conditions, this is the special, grid-aligned case of jump corrections used in the Explicit Jump Immersed Interface method. Fast elastostatic solvers for periodic boundary conditions in two and three dimensions can also be based on the FFT. From the periodic solvers we derive fast solvers for the new 'normal' boundary conditions and essential boundary conditions on rectangular parallelepipeds. The periodic case allows a simple proof of existence and uniqueness of the solutions to the discretization of normal boundary conditions. Numerical examples demonstrate the efficiency of the fast elastostatic solvers for non-periodic boundary conditions. More importantly, the fast solvers on rectangular parallelepipeds can be used together with the Immersed Interface Method to solve problems on non-rectangular domains with general boundary conditions. Details of this are reported in the preprint The Explicit Jump Immersed Interface Method for 2D Linear Elastostatics by the author.
In this paper the effect of changing from the traditional NTP coolant, hydrogen, to several alternative coolants were studied. Hydrogen is generally chosen as an NTP coolant, since its use maximizes the specific impulse for a given operating temperature. However, there are situations in which it may not be available or optimal. The alternative coolants which were considered are ammonia, methane, and carbon dioxide. A particle bed reactor (PBR) generating 200 MW and cooled by hydrogen was used as the baseline against which all the comparisons were made. Both 19 and 37 element cores were considered. The larger number of elements was found to be necessary in the case of carbon dioxide. The coolant reactivity worth was found to be directly proportional to the hydrogen coolant content. It was found that due to differences in the thermophysical proportions of the coolant that it would not be possible to use one reactor for all the coolants. The reactor would have to be constructed specifically for a coolant type.
Two distinct phases of apoptosis in mammary gland involution: proteinase-independent and -dependent pathways
Postlactational involution of the mammary gland is characterized by two distinct physiological events: apoptosis of the secretory, epithelial cells undergoing programmed cell death, and proteolytic degradation of the mammary gland basement membrane. We examined the spatial and temporal patterns of apoptotic cells in relation to those of proteinases during involution of the BALB/c mouse mammary gland. Apoptosis was almost absent during lactation but became evident at day 2 of involution, when {beta}-casein gene expression was still high. Apoptotic cells were then seen at least up to day 8 of involution, when {beta}-casein gene expression was being extinguished. Expression of sulfated glycoprotein-2 (SGP-2), interleukin-1{beta} converting enzyme (ICE) and tissue inhibitor of metalloproteinases-1 was upregulated at day 2, when apoptotic cells were seen initially. Expression of the matrix metalloproteinases gelatinase A and stromelysin-1 and the serine proteinase urokinase-type plasminogen activator, which was low during lactation, was strongly upregulated in parallel starting at day 4 after weaning, coinciding with start of the collapse of the lobulo-alveolar structures and the intensive tissue remodeling in involution. The major sites of mRNA synthesis for these proteinases were fibroblast-like cells in the periductal stroma and stromal cells surrounding the collapsed alveoli, suggesting that the degradative phase of involution is due to a specialized mesenchymal-epithelial interaction. To elucidate the functional role of these proteinases during involution, at the onset of weaning we treated mice systemically with the glucocorticoid hydrocortisone, which is known to inhibit mammary gland involution. Although the initial wave of apoptotic cells appeared in the lumina of the gland, the dramatic regression and tissue remodeling usually evident by day 5 was substantially inhibited by systemic treatment with hydrocortisone. mRNA and protein for gelatinase A, stromelysin-1 and uPA were weakly induced, if at all, in hydrocortisonetreated mice. Furthermore, mRNA for membrane-type matrix metalloproteinase decreased after hydrocortisone treatment ...
Alpha1 and Alpha2 Integrins Mediate Invasive Activity of Mouse Mammary Carcinoma Cells through Regulation of Stromelysin-1 Expression
Tumor cell invasion relies on cell migration and extracellular matrix proteolysis. We investigated the contribution of different integrins to the invasive activity of mouse mammary carcinoma cells. Antibodies against integrin subunits {alpha}6 and {beta}1, but not against {alpha}1 and {alpha}2, inhibited cell locomotion on a reconstituted basement membrane in two-dimensional cell migration assays, whereas antibodies against {beta}1, but not against a6 or {alpha}2, interfered with cell adhesion to basement membrane constituents. Blocking antibodies against {alpha}1 integrins impaired only cell adhesion to type IV collagen. Antibodies against {alpha}1, {alpha}2, {alpha}6, and {beta}1, but not {alpha}5, integrin subunits reduced invasion of a reconstituted basement membrane. Integrins {alpha}1 and {alpha}2, which contributed only marginally to motility and adhesion, regulated proteinase production. Antibodies against {alpha}1 and {alpha}2, but not {alpha}6 and {beta}1, integrin subunits inhibited both transcription and protein expression of the matrix metalloproteinase stromelysin-1. Inhibition of tumor cell invasion by antibodies against {alpha}1 and {alpha}2 was reversed by addition of recombinant stromelysin-1. In contrast, stromelysin-1 could not rescue invasion inhibited by anti-{alpha}6 antibodies. Our data indicate that {alpha}1 and {alpha}2 integrins confer invasive behavior by regulating stromelysin-1 expression, whereas {alpha}6 integrins regulate cell motility. These results provide new insights into the specific functions of integrins during tumor cell invasion.
A Novel Function for the nm23-Hl Gene: Overexpression in Human Breast Carcinoma Cells Leads to the Formation of Basement Membrane and Growth Arrest
We have developed a culture system using reconstituted basement membrane components in which normal human mammary epithelial cells exhibit several aspects of the development and differentiation process, including formation of acinar-like structures, production and basal deposition of basement membrane components, and production and apical secretion of sialomucins. Cell lines and cultures from human breast carcinomas failed to recapitulate this process. The data indicate the importance of cellular interactions with the basement membrane in the regulation of normal breast differentiation and, potentially, its loss in neoplasia. Our purpose was to use this assay to investigate the role of the putative metastasis suppressor gene nm23-H1 in mammary development and differentiation. The metastatic human breast carcinoma cell line MDA-MB-435, clones transfected with a control pCMVBamneo vector, and clones transfected with pCMVBamneo vector containing nm23-H1 complementary DNA (the latter of which exhibited a substantial reduction in spontaneous metastatic potential in vivo) were cultured within a reconstituted basement membrane. Clones were examined for formation of acinus-like spheres, deposition of basement membrane components, production of sialomucin, polarization, and growth arrest. In contrast to the parental cell line and control transfectants, MDA-MB-435 breast carcinoma cells overexpressing Nm23-H1 protein regained several aspects of the normal phenotype within reconstituted basement membrane. Nm23-H1 protein-positive cells formed organized acinus-like spheres, deposited the basement membrane components type IV collagen and, to some extent, laminin to the outside of the spheres, expressed sialomucin, and growth arrested. Growth arrest of Nm23-H1 protein-positive cells was preceded by and correlated with formation of a basement membrane, suggesting a causal relationship. The data indicate a previously unidentified cause-and-effect relationship between nm23-H1 gene expression and morphological-biosynthetic-growth aspects of breast differentiation in this model system. While the basement membrane microenvironment is capable of directing the differentiation of normal human breast cells, neoplastic transformation abrogates this relationship, suggesting that intrinsic ...
Human Mammary Luminal Epithelial Cells Contain Progenitors to Myoepithelial Cells
The origin of the epithelial and myoepithelial cells in the human breast has not been delineated. In this study we have addressed whether luminal epithelial cells and myoepithelial cells are vertically connected, i.e., whether one is the precursor for the other. We used a primary culture assay allowing preservation of basic phenotypic traits of luminal epithelial and myoepithelial cells in culture. The two cell types were then separated immunomagnetically using antibodies directed against lineage-specific cell surface antigens into at best 100% purity. The cellular identity was ascertained by cytochemistry, immunoblotting, and 2-D gel electrophoresis. Luminal epithelial cells were identified by strong expression of cytokeratins 18 and 19 while myoepithelial cells were recognized by expression of vimentin and {alpha}-smooth muscle actin. We used a previously devised culture medium (CDM4) that allows vigorous expansion of proliferative myoepithelial cells and also devised a medium (CDM6) that allowed sufficient expansion of differentiated luminal epithelial cells based on addition of hepatocyte growth factor/scatter factor. The two different culture media supported each lineage for at least five passages without signs of interconversion. We used parallel cultures where we switched culture media, thus testing the ability of each lineage to convert to the other. Whereas the myoepithelial lineage showed no signs of interconversion, a subset of luminal epithelial cells, gradually, but distinctly, converted to myoepithelial cells. We propose that in the mature human breast, it is the luminal epithelial cell compartment that gives rise to myoepithelial cells rather than the other way around.
Expression of Autoactivated Stromelysin-1 in Mammary Glands of Transgenic Mice Leads to a Reactive Stroma During Early Development
Extracellular matrix and extracellular matrix-degrading matrix metalloproteinases play a key role in interactions between the epithelium and the mesenchyme during mammary gland development and disease. In patients with breast cancer, the mammary mesenchyme undergoes a stromal reaction, the etiology of which is unknown. We previously showed that targeting of an autoactivating mutant of the matrix metalloproteinase stromelysin-1 to mammary epithelia of transgenic mice resulted in reduced mammary function during pregnancy and development of preneoplastic and neoplastic lesions. Here we examine the cascade of alterations before breast tumor formation in the mammary gland stroma once the expression of the stromelysin-1 transgene commences. Beginning in postpubertal virgin animals, low levels of transgene expression in mammary epithelia led to increased expression of endogenous stromelysin-1 in stromal fibroblasts and up-regulation of other matrix metalloproteinases, without basement membrane disruption. These changes were accompanied by the progressive development of a compensatory reactive stroma, characterized by increased collagen content and vascularization in glands from virgin mice. This remodeling of the gland affected epithelial-mesenchymal communication as indicated by inappropriate expression of tenascin-C starting by day 6 of pregnancy. This, together with increased transgene expression, led to basement membrane disruption starting by day 15 of pregnancy. We propose that the highly reactive stroma provides a prelude to breast epithelial tumors observed in these animals. Epithelial development depends on an exquisite series of inductive and instructive interactions between the differentiating epithelium and the mesenchymal (stromal) compartment. The epithelium, which consists of luminal and myoepithelial cells, is separated from the stroma by a basement membrane (BM), which plays a central role in mammary gland homeostasis and gene expression. In vivo, stromal cells produce fibronectin, collagens, proteoglycans, and some components of the BM, as well as a number of proteinases that can effectively degrade BM constituents. Stromal and epithelial cells of the ...
Mammary gland tumor formation in transgenic mice overexpressing stromelysin-1
An intact basement membrane (BM) is essential for the proper function, differentiation and morphology of many epithelial cells. The disruption or loss of this BM occurs during normal development as well as in the disease state. To examine the importance of BM during mammary gland development in vivo, we generated transgenic mice that inappropriately express autoactivating isoforms of the matrix metalloproteinase stromelysin-1. The mammary glands from these mice are both functionally and morphologically altered throughout development. We have now documented a dramatic incidence of breast tumors in several independent lines of these mice. These data suggest that overexpression of stromelysin-1 and disruption of the BM may be a key step in the multi-step process of breast cancer.
Self-Dual Supergravity from N = 2 Strings
A new heterotic N = 2 string with manifest target space supersymmetry is constructed by combining a conventional N = 2 string in the right-moving sector and a Green-Schwarz-Berkovits type string in the left-moving sector. The corresponding sigma model is then obtained by turning on background fields for the massless excitations. We compute the beta functions and we partially check the OPE's of the superconformal algebra perturbatively in {alpha}{prime}, all in superspace. The resulting field equations describe N = 1 self-dual supergravity.
D to A Line Tuning
Although in the past the D to A line was well tuned, through the course of years of operations it has not kept up with changes in the Debuncher and Accumulator. The beam is now steered well off center in SEM's 806 and 807, and is possibly scraping in TQ5. In addition, there is some evidence that the beta functions are not matched, causing emmitance blowup of the beam. As the cycle time of the main ring has decreased these limitations have become a significant limitation to the stacking rate.
An Updated AP2 Beamline TURTLE Model
This note describes a TURTLE model of the AP2 beamline. This model was created by D. Johnson and improved by J. Hangst. The authors of this note have made additional improvements which reflect recent element and magnet setting changes. The magnet characteristics measurements and survey data compiled to update the model will be presented. A printout of the actual TURTLE deck may be found in appendix A.
A Silicon Track Trigger for the D0 Experiment in Run II
No abstract prepared.
Reactor Refueling - Interim Decay Storage (FFTF)
The IDS facility is located between the CLEM rails and within the FFTF containment building. It is located in a rectangular steel-lined concrete cell which lies entirely below the 550 ft floor level with the top flush with the 550 ft floor level. The BLTC rails within containment traverse the IDS cover (H-4-38001). The facility consists of a rotatable storage basket submerged in liquid sodium which is contained in a stainless steel tank. The storage positions within the basket are arranged so that it is not physically possible to achieve a critical array. The primary vessel is enclosed in a secondary guard tank of such size and arrangement that, should a leak develop in the primary tank, the sodium level would not fall below the top of the fueled section of the stored core components or test assemblies. The atmosphere outside the primary vessel, but within the concrete cell, is nitrogen which also serves as a heat transfer medium to control the cell temperature. To provide space for the storage of test assemblies such as the OTA and CLIRA, 10 storage tubes (each approximately 43-1/4 ft long) are included near the center of the basket. This arrangement requires that the center of the primary vessel be quite deep. In this region, the primary vessel extends downward to elevation 501 ft 6 inches while the guard tank reaches 500 ft 4 inches. The floor of the cell is at 499 ft a inches which is 51 ft below the operating room floor. Storage positions are provided for 112 core components in the upper section of the storage basket. These positions are arranged in four circles, all of which are concentric with the test element array and the storage basket. The primary vessel and the guard tank are shaped to provide the ...
FY99 Status Report on the HSV
'The HSV in storage in MTF has been monitored during FY99, and its overpressure has been sampled and analyzed. The HSV''s internal pressure continues to rise slowly, and the overpressure still analyzes as 100 percent 3He. The titanium tritide sample that was to be monitored annually and which had developed a leak last year has been repaired and isotherms measured. Unfortunately the sample was showing significant unexpected 3He release, so the isotherm data is corrupted by unknown levels of 3He. This release has disqualified this sample for future use, as it is now seriously divergent from the HSV material. A different sample must be selected for subsequent studies.The unexpected 3He releases of the Ti-3 sample and the possible release in other Ti samples have raised a serious issue. It should be determined why this release is occurring, so that an unexpected release of 3He during HSV unloading can be assessed as unlikely.'
Hanford Immobilized Low-Activity Waste Product Acceptance Test Plan
'The Hanford Site has been used to produce nuclear materials for the U.S. Department of Energy (DOE) and its predecessors. A large inventory of radioactive and mixed waste, largely generated during Pu production, exists in 177 underground single- and double-shell tanks. These wastes are to be retrieved and separated into low-activity waste (LAW) and high-level waste (HLW) fractions. The DOE is proceeding with an approach to privatize the treatment and immobilization of Handord''s LAW and HLW.'
Lifting Beam Design/Analysis for the Data Acquisition and Control System Trailer
This supporting document details calculations completed to properly design an adjustable lifting beam. The main use of the lifting beam is to hoist the Data Acquisition and Controls Systems (DACS) trailer over a steam line. All design work was completed using the American Institute of Steel Construction, Manual of Steel Construction (AISC, 1989) and Hanford Hoisting and Rigging Manual (WHC, 1992).
Mechanical properties of thermally aged cast stainless steels from shippingport reactor components.
Thermal embrittlement of static-cast CF-8 stainless steel components from the decommissioned Shippingport reactor has been characterized. Cast stainless steel materials were obtained from four cold-leg check valves, three hot-leg main shutoff valves, and two pump volutes. The actual time-at-temperature for the materials was {approx}13 y at {approx}281 C (538 F) for the hot-leg components and {approx}264 C (507 F) for the cold-leg components. Baseline mechanical properties for as-cast material were determined from tests on either recovery-annealed material, i.e., annealed for 1 h at 550 C and then water quenched, or material from the cooler region of the component. The Shippingport materials show modest decreases in fracture toughness and Charpy-impact properties and a small increase in tensile strength because of relatively low service temperatures and ferrite content of the steel. The procedure and correlations developed at Argonne National Laboratory for estimating mechanical properties of cast stainless steels predict accurate or slightly lower values for Charpy-impact energy, tensile flow stress, fracture toughness J-R curve, and JIC of the materials. The kinetics of thermal embrittlement and degree of embrittlement at saturation, i.e., the minimum impact energy achieved after long-term aging, were established from materials that were aged further in the laboratory. The results were consistent with the estimates. The correlations successfully predicted the mechanical properties of the Ringhals 2 reactor hot- and crossover-leg elbows (CF-8M steel) after service of {approx}15 y and the KRB reactor pump cover plate (CF-8) after {approx}8 y of service.
Effects of thermal aging on fracture toughness and charpy-impact strength of stainless steel pipe welds.
The degradation of fracture toughness, tensile, and Charpy-impact properties of Type 308 stainless steel (SS) pipe welds due to thermal aging has been characterized at room temperature and 290 C. Thermal aging of SS welds results in moderate decreases in Charpy-impact strength and fracture toughness. For the various welds in this study, upper-shelf energy decreased by 50-80 J/cm{sup 2}. The decrease in fracture toughness J-R curve or JIC is relatively small. Thermal aging had little or no effect on the tensile strength of the welds. Fracture properties of SS welds are controlled by the distribution and morphology of second-phase particles. Failure occurs by the formation and growth of microvoids near hard inclusions; such processes are relatively insensitive to thermal aging. The ferrite phase has little or no effect on the fracture properties of the welds. Differences in fracture resistance of the welds arise from differences in the density and size of inclusions. Mechanical-property data from the present study are consistent with results from other investigations. The existing data have been used to establish minimum expected fracture properties for SS welds.
Estimation of fracture toughness of cast stainless steels during thermal aging in LWR systems - Revison 1.
This report presents a revision of the procedure and correlations presented earlier in NUREG/CR-4513, ANL-90/42 (June 1991) for predicting the change in mechanical properties of cast stainless steel components due to thermal aging during service in light water reactors at 280-330 C (535-625 F). The correlations presented in this report are based on an expanded data base and have been optimized with mechanical-property data on cast stainless steels aged up to {approx}58,000 h at 290-350 C (554-633 F). The correlations for estimating the change in tensile stress, including the Ramberg/Osgood parameters for strain hardening, are also described. The fracture toughness J-R curve, tensile stress, and Charpy-impact energy of aged cast stainless steels are estimated from known material information. Mechanical properties of a specific cast stainless steel are estimated from the extent and kinetics of thermal embrittlement. Embrittlement of cast stainless steels is characterized in terms of room-temperature Charpy-impact energy. The extent or degree of thermal embrittlement at 'saturation,' i.e., the minimum impact energy that can be achieved for a material after long-term aging, is determined from the chemical composition of the steel. Charpy-impact energy as a function of time and temperature of reactor service is estimated from the kinetics of thermal embrittlement, which are also determined from the chemical composition. The initial impact energy of the unaged steel is required for these estimations. Initial tensile flow stress is needed for estimating the flow stress of the aged material. The fracture toughness J-R curve for the material is then obtained by correlating room-temperature Charpy-impact energy with fracture toughness parameters. The values of JIC are determined from the estimated J-R curve and flow stress. A common 'predicted lower-bound' J-R curve for cast stainless steels of unknown chemical composition is also defined for a given grade of steel, range of ferrite content, and ...
Review of environmental effects on fatigue crack growth of austenitic stainless steels.
Fatigue and environmentally assisted cracking of piping, pressure vessel cladding, and core components in light water reactors are potential concerns to the nuclear industry and regulatory agencies. The degradation processes include intergranular stress corrosion cracking of austenitic stainless steel (SS) piping in boiling water reactors (BWRs), and propagation of fatigue or stress corrosion cracks (which initiate in sensitized SS cladding) into low-alloy ferritic steels in BWR pressure vessels. Crack growth data for wrought and cast austenitic SSs in simulated BWR water, developed at Argonne National Laboratory under US Nuclear Regulatory Commission sponsorship over the past 10 years, have been compiled into a data base along with similar data obtained from the open literature. The data were analyzed to develop corrosion-fatigue curves for austenitic SSs in aqueous environments corresponding to normal BWR water chemistries, for BWRs that add hydrogen to the feedwater, and for pressurized water reactor primary-system-coolant chemistry. The corrosion-fatigue data and curves in water were compared with the air line in Section XI of the ASME Code.
Tensile-property characterization of thermally aged cast stainless steels.
The effect of thermal aging on tensile properties of cast stainless steels during service in light water reactors has been evaluated. Tensile data for several experimental and commercial heats of cast stainless steels are presented. Thermal aging increases the tensile strength of these steels. The high-C Mo-bearing CF-8M steels are more susceptible to thermal aging than the Mo-free CF-3 or CF-8 steels. A procedure and correlations are presented for predicting the change in tensile flow and yield stresses and engineering stress-vs.-strain curve of cast stainless steel as a function of time and temperature of service. The tensile properties of aged cast stainless steel are estimated from known material information, i.e., chemical composition and the initial tensile strength of the steel. The correlations described in this report may be used for assessing thermal embrittlement of cast stainless steel components.
A 10 um Resolution Secondary Emission Monitor for Fermilab's Targeting Station
Improvement in focusing the proton beam onto the antiproton production target necessitates the development of a higher resolution beam profile monitor. Two designs for the construction of a multiwire profile mointor grid are presented. The first is a conventional strung and tensioned Ti wire design. The second is a photo etched Ti grid of wires bonded to a ceramic substrate. Both have a central wire spacing of 125 {mu}m. The completed beam profile monitors are designed to operate in a 120 GeV beam pulse of 5 x 10{sup 12} protons with a 1.5{mu}s duration and will be installed in late 1993.
The Design and Performance of a High Sensitivity Loss Monitor System for Use in the Fermilab Antiproton Rings
As part of a general laboratory cleanup of hazardous materials from the accelerator enclosures they have replaced the liquid scintillator based paint can type beam loss monitors with improved loss monitors based on plastic scintillator. This paper describes the design of these counters and their performance in the PBAR source.
Design of 2-4 GHz Equalizers for the Antiproton Accumulator Stacktail System
The antiproton source at Fermilab requires storage of antiprotons during the production of antiprotons. A fundamental part of the storage process involves stochastic cooling, which requires that the frequency spectrum from the pickups has notches at the revolution frequency and harmonics of the revolution frequency of the antiprotons in the storage ring. A system has been developed for broadband notches but suffers from dispersion. The dispersion inhibits the cooling process and therefore an equalizer is required. The process for designing the equalizers is described and results shown.
The Hybrid Emulsion Detector for MINOS R&D Proposal
The MINOS (Main Injector Neutrino Oscillation Search) experiment is designed to search for neutrino oscillations with a sensitivity significantly greater than has been achieved to date. The phenomenon of neutrino oscillations, whose existence has not been proven convincingly so far, allows neutrinos of one "flavor" (type) to slowly transform themselves into another flavor, and then back again to the original flavor, as they propagate through space or matter. The MINOS experiment is optimized to explore the region of neutrino oscillation "parameter space" suggested by previous investigations of atmospheric neutrinos: the Kamiokande, IMB, Super-Kamiokande and Soudan 2 experiments. The study of oscillations in this region with a neutrino beam from the Main Injector requires measurements of the beam after a very long flight path. This in turn requires an intense neutrino beam and a massive detector in order to have an adequate event rate at a great distance from the source. We propose to enhance significantly the physics capabilities of the MINOS experiment by the addition of a Hybrid Emulsion Detector at Soudan, capable of unambigous identification of the neutrino flavor. Recent developments in emulsion experiments make such a detector possible, although significant technological challenges must be overcome. We propose to initiate an R&D effort to identify major potential problems and to develop practical solutions to them. This proposal is meant to be a summary of the work we feel is needed before a credible conceptual design report can be produced. It summarizes both the tasks that need to be done and new incremental resources that are required to perform them. It is our expectation that various individual institutions (those currently in MINOS and others anticipating joining) will submit separate individual funding requests, to funding agencies in both US and abroad, to provide most of the resources listed in Chapter 5. ...
Four-Plate Pick-Up Capacitance and Sensitivity Calculations
The goal of calculations presented in this note is to find and maximize the sensitivity of a quadrupole pick-up currently being designed. The calculations are made using the CERN package Poisson. The range of electrode widths under consideration is:.006m < w < .03. Studies indicate that sensitivity is maximized in this range by the smallest width plate if the electronics contributes negligible capacitance. The plate size for which the sensitivity is optimized increases with increasing electronics capacitance. As well, 6cm and 8cm outer shells of both circular and square geometry are considered. An 8cm square quadrupole pickup yields the higher sensitivity.
Identification of New Operating Tunes for the Accumulator
Our current operating tunes for the accumulator, 6.606 and 8.610, are so close together that it is almost impossible to eliminate coupling completely even at the core orbit, and all the other orbits are nearly 100% coupled. Not only does this make diagnostic information difficult to interpret, but it also reduces the transverse acceptance of the accumulator. I propose that we attempt to find another operating point farther away from the coupling resonance. The attached plots show most of the operating range with a horizontal tune between 6.4 and 6.9, and a vertical tune from 8.4 to 8.9. Please note that the T128 program sometimes forgets to draw some resonance lines on the plot, so if a possible operating point is found it is necessary to plot it with several different scales to make sure that all the resonance lines are visible. The top plot shows our current operating point. The second plot shows a series of gaps near the tune 6.560 and 8.430. The third and fourth plots show a blowup of one of the identified gaps with resonances to 15th and 18th order displayed. The rest of the plots are included for completeness. The operating point shown in the third plot gives about 60 times more separation from the coupling resonance than we now have. I think it would be worthwhile to spend a few shifts to identify the proper bus currents for this operating point. We should then try to stack at this point to see if there is any advantage to running without coupling.
Analyzing Power $A_n$ in High P-Transverse Squared Proton-Proton Elestic Scattering
This is a proposal to measure the Analyzing Power $A_n$ in Proton-Proton Elestic Scattering at High P-Transverse Squared of 1 to 12 (GeV/c)<sup>2</sup> using a 120 GeV unpolarized extracted proton beam from Fermilab's Main Injector starting in 2001.
Calibration of Accumulator and Debuncher Scrapers
During the past week a careful calibration of the accumulator and debuncher scrapers was made. The procedure was to measure the actual scraper movement relative to some fixed external reference point with a caliper while observing the readback of the associated ACNET device on a VAX console. The results of this calibration are summarized.
Guidelines for the Calculation of the Accumulator Magnet Bus Ramps for Fermilab Experiment E835
This report lists the steps that are required to calculate deceleration ramps for all relevant Accumulator devices. The ramps used for the 1996-97 fixed target run (experiment E835) are saved in files associated with ACNET console application PA1627 (PAUX RAMP DEVELOP). These ramps cannot be re-used because the Accumulator {gamma}{sub t} upgrade has significantly changed the lattice since the last time the ramps were used. Consequently, new deceleration ramps must be calculated and commissioned before the next fixed target run. The deceleration ramp for a particular device is a table that gives the sequence of set values sent to the device as the ramp is executed. The 1997 ramps consist of ramp tables for 100 devices. Appendix 1 gives a list of the devices ramped. Most of these devices will still require ramps for the next fixed target run. Future decelerations will also require ramps for the quadrupole magnet shunts that were installed as part of the {gamma}{sub t} upgrade. Additionally, ramps must be constructed for the two skew-sextupole magnets that will be installed during the summer of 1999.
Fermilab Test Beam Proposal for Diamond Tracking Detectors
No abstract prepared.
Effect of Melting on Target Performance
The brightness of the antiproton source increases as the proton beam spot size on the target is reduced. The RMS beam spot size may be reduced to below {sigma}{sub b} = 0.1 mm, before competing sources of emittance limit the achievable yield. At the same time, the density of energy deposition increases rapidly as the radius is reduced. Thus operation of the target at the highest yields subjects the target to very high peak energy deposition E{sub m}. Fits to the Monte-Carlo calculations of target yield and energy deposition from Ref. 1 are plotted in Figure 1. Experience has shown little or no sign of damage in copper targets up to about 500 J/g. If, as the energy density is increased, rupture of the copper target due to overpressure or shock-induced tensile stress does not occur, the ultimate brightness of the target will be limited by melting of the target material and consequent density depletion. This outcome was anticipated early in development of the antiproton source [Ref. 2]. The current memo addresses the melting problem with the goal of predicting the practical limitations of the target as the proton intensity is increased to 5 x 10{sup 12} protons per pulse. The predictions are made in a way that can be experimentally tested. They may also help determine the utility of a beam sweeping system.
Debuncher Cooling Limitations to Stacking
During the January studies period we performed studies to determine the effect that debuncher cooling has on the stacking rate. Two different sets of measurements were made separated by about a week. Most measurements reported here are in PBAR log 16, page 243-247. These measurements were made by changing the accelerator timeline to give about 6 seconds between 29's, and then gating the cooling systems to simulate reduced cycle times. For the measurement of the momentum cooling effectiveness the gating switches could not be made to work, so the timeline was changed for each measurement. The cooling power of all three systems was about 800 watts for the tests reported here. We now regularly run at 1200 watts per system.
Debuncher Microwave Absorber Tests of January 1992
This paper describes the tests performed on the microwave absorbers placed in the Debuncher to replace the existing microwave cutoffs. The purpose of the microwave cutoffs is to reduce the transmission of microwave energy through the beam pipe. The old microwave cutoffs consisted of a stainless steel beam pipe of approximately 2.8 inches inside diameter into which a glass tube with an inside diameter of 1.835 inches was placed. The glass tube was coated with a thin coat of microwave absorbing material on its outside. Three of these cutoffs were installed in the Debuncher at locations D6Q5, D1Q7, and D4Q10 (see Figure 1). However, the glass tube was removed from the cutoff at D4Q10 leaving only the metal beam pipe. Please note that there was not an old style microwave cutoff installed at location D2Q09. It was felt that the glass tube cutoff was an aperture restriction in the Debuncher with its small (1.8 inch) inside diameter. It was decided that new cutoffs would be needed that would increase the aperture. The new microwave absorbers consist of a four inch stainless steel beam pipe into which eleven dielectric cores are inserted separated by aluminum spacers. The spacing allows adjustment of the frequency response of the absorber assembly. The inside diameter is 3 inches thus providing an increase of 1.2 inches over the old cutoffs. The new absorbers will be installed at four locations as shown in Figure 1.
Debuncher Momentum Aperture Measurements
During the November 1990 through January 1991 {bar p} studies period, the momentum aperture of the beam in the debuncher ring was measured. The momentum aperture ({Delta}p/p) was found to be 4.7%. The momentum spread was also measured with beam bunch rotation off. A nearly constant particle population density was observed for particles with {Delta}p/p of less than 4.3%, indicating virtually unobstructed orbits in this region. The population of particles with momenta outside this aperture was found to decrease rapidly. An absolute or 'cut-off' momentum aperture of {Delta}p/p = 5.50% was measured.
Deceleration Orbit Improvements
During the accelerator studies period of 12/90-1/91 much study time was dedicated to improving the E760 deceleration ramps. 4 general goals were in mind: (1) Reduce the relative orbit deviations from the nominal reference orbit as much as possible. This reduces the potential error in the orbit length calculation - which is the primary source of error in the beam energy calculation. (2) Maximize the transverse apertures. This minimizes beam loss during deceleration and during accidental beam blow-ups. (3) Measure and correct lattice parameters. Knowledge of {gamma}{sub T}, {eta}, Q{sub h}, Q{sub v}, and the dispersion in the straight sections allows for a more accurate energy calculation and reliable SYNCH calculations. (4) Minimize the coupling. This allows one to discern between horizontal and vertical tunes.
BPM System Improvements
During the accelerator studies period of 12/90 through 1/91 the Accumulator BPM system was investigated in some detail in an effort to improve its reliability and accuracy in making closed orbit measurements. The motivation for this is to try and improve the beam energy resolution for E760. The relativistic {beta} of the {bar p} is given by {beta} = f{sub R}L/c where f{sub R} is the revolution frequency, L is the orbit length ({approx} 474050mm), and c is the speed of light. Hence, the error in {beta} is given by d{beta}/{beta} = df{sub R}/f{sub R} + dL/L. Since df{sub R}/f{sub R} is {approx} 2 x 10{sup -7}, the main contribution to the error comes from dL. During the E760 run of 5/90 to 9/90 dL was estimated to be {approx} 1mm. It is thought that this can be reduced to {approx} .25mm with proper use of the present BPM system. L is given by L = L{sub 0} + {delta}L where L{sub 0} is the accurately known orbit length of a reference orbit (extracted from an energy scan of the J/{Psi} or {Psi}{prime}), and {delta}L is the difference orbit between the current orbit and the reference orbit. SL is calculated in the 1st approximation by {delta}L = {Sigma}{sub i}C{sub i}{Sigma}{sub j}{Delta}BPM{sub ij} where {Delta}BPM{sub ij} is the horizontal difference orbit at the ith BPM in the jth sector and C{sub i} are constants depending upon the location of the BPM pickup and the strength of the quadrupoles. Table I lists the constants C{sub i}, and Fig. 1 shows a typical difference orbit, {Delta}BPM{sub ij}. These studies were all done with 'reverse protons' and concentrated on closed orbit measurements with the Accumulator horizontal BPMs. The low frequency (H=2) mode of the BPM system is used in all cases, therefore it is ...
Beam Test of High-Performance Hadron Calorimeter for Future Linear Colliders
No abstract prepared.
Antiproton Extraction in the Fermilab Antiproton Accumulator
The RF and other manipulations required to extract antiprotons from the Accumulator core for Collider operation are described. ESME simulations of the motion in longitudinal phase space are shown. Measurements of the emittances of the extracted antiprotons are presented. The effect of the unstacking process on the core longitudinal and transverse emittances is examined and recent performance is also presented.
AP0 Target Vault Shielding Study
Efforts are currently underway to redesign the neutron covers to meet radiation-safety guidelines, with the goal of reducing the radiation level over the vault by at least a factor of 100. This note describes the results of measurements of radiation attenuation by sample shields. The purpose of the shielding study is to provide data for the redesign of the neutron covers. The radiation escaping from the neutron covers appears to be predominantly gammas. In addition, there is a small, more penetrating component, which may consist of energetic (&gt;200 MeV) neutrons leaking past the neutron covers. Reduction of the measured radiation by more than an order of magnitude is easily achieved by placing a 6-inch steel plate over the existing neutron covers. However, the desired reduction by two orders of magnitude requires further attenuation of the more penetrating component. The conclusion of the study is that 48 inches of concrete should adequately attenuate the radiation.
On the Geometry of the Quantum Poincare Group
We review the construction of the multiparametric inhomogeneousorthogonal quantum group ISO{sub q,r}(N) as a projection from SO{sub q,r}(N+2), and recall the conjugation that for N=4 leads to the quantum Poincare group. We study the properties of the universal enveloping algebra U{sub q,r}(iso(N)), and give an R-matrix formlation. A quantum Lie algebra and a bicovariant differential calculus on twisted ISO(N) are found.
String Field Equations from Generalized Sigma Model
We propose a new approach for deriving the string field equations from a general sigma model on the world-sheet. This approach leads to an equation which combines some of the attractive features of both the renormalization group method and the covariant beta function treatment of the massless excitations. It has the advantage of being covariant under a very general set of both local and non-local transformations in the field space. We apply it to the tachyon, massless and first massive level, and show that the resulting field equations reproduce the correct spectrum of a left-right symmetric closed bosonic string.
Site Power
No abstract prepared.
A Review of the 1991 E760 Run
The 1991 E760 run was highly successful. This note is an attempt to record some important information regarding Accumulator operation during the run, so that it will be easily accessible for the next E760 run. The topics are not in any particularly relevant order, but are taken mostly from a seminar given by M. Church on 2/13/92. Much ramp data resides in the 'E760 Ramps Notebook' and much other data resides in E760 logbooks V, VI, VII, and VIII. Table 1 summarizes the data collected during the run. Fig. 1 shows the luminosity collected week by week and the average stacking rate per stack. Fig. 2 shows the luminosity integrated through the run. A total of 31 pb{sup -1} was collected. Fig 3. shows a typical deceleration (above transition) with a typical efficiency of 95%. Early in the run the efficiency was very close to 100%. I suspect there was an aperture restriction - possibly a momentum aperture limitation as we wandered too close to the edge of the momentum aperture. The deceleration efficiency really should be 100%. Fig. 4 shows a typical data-taking cycle. The break point 2/3rds through the data-taking is a deceleration to the {eta}{sub c}. Fig. 4a and 4b show horizontal and vertical aperture as a function of momentum for the 1990 ramps and 1991 ramps as measured in Jan. 1991. During the run, the actual apertures were known to be smaller. The problem of radiation during stacking was solved during this run by the addition of more shielding. Fig. 4c shows the final layout of shielding blocks. A 40 mA stack gave about 3 mrads of radiation in the Pb-G as measured by standard chipmunks. The total amount of radiation received during the run was about 100 rads - bringing the total to about 200 ...
Observation of the Coalescing of Beam Into an Asymmetric RF Bucket by Stochastic Cooling
Antiprotons in the debuncher ring at Fermilab have been observed to be bunched outside of the 'barrier bucket' when cooled to small {Delta}p/p with the stochastic cooling. This bunching occurs in the same location as a very small stable bucket in the RF wave form. The stochastic cooling appears to be causing beam that is originally uniformly distributed to be captured by this stable bucket.
Performance of the Upgraded Stacktail Momentum Cooling System in the Fermilab Antiproton Source
Major changes in the Stacktail Momentum Stochastic Cooling system have resulted in an improved stacking rate as well as the capability to stack larger quantities of antiprotons. Both these effects result in higher initial and integrated luminosity for colliding beam physics. An overview of the changes and actual system performance is presented.
Power Handling Upgrade of Debuncher Stochastic Cooling Kicker Tanks
The Debuncher Stochastic Cooling Power Upgrade tripled the number of TWTs from 16 to 48. The power desired for each TWT is about 120 W. The debuncher stochastic cooling system contains 6 kicker tanks (4 short tanks, 2 long tanks) with a total number of 64 microwave feedthroughs. Thus, the power per feedthrough increased from 30W to 90 W as a result of the upgrade. The kicker array inside the vacuum tank is connected to the microwave feedthrough on the vacuum flange by means of a rigid 0.25-inch diameter coaxial cable which is 12-inch long. With 90 W flowing through the coax, the amount of power dissipated is 2.5 W. A lab test on a single debuncher kicker tank showed that this power dissipation caused the temperature of the coaxial cable to rise to greater than 175 C. At this point the Teflon dielectric of the coax and the solder joints in the coax might seriously degrade. As a temporary stop-gap solution, transistor heat sinks were placed around the outside of the coaxial cable. (The amount of heat sinks need for all the cables was 3400.) The primary function of the transistor heat sinks around the coaxial cable was to remove thermal energy generated in the coax by radiation. Lab tests showed that the with the heat sinks in place, the temperature of the coax was brought below 110 C. However, with the tanks installed, the maximum total amount of power that could be applied to the tanks and keep the ion pumps safely below their trip level (The trip level on the ion pumps is about 1 x 10{sup -6} Torr. We kept the ion pumps at about 3 x 10{sup -7} Torr.) was about 2250 W or 35 W per feedthrough. The ion pumps with the highest pressure ...
Summary of Recent Target Studies
This report describes recent measurements that have been performed with the new target stack (Fig. 1). Highlights of these measurements are: (1) Pbar yields of nickel and powdered rhenium are comparable to that of copper. (2) Enhancement of pbar yield at the interface between copper and aluminum disks in the target stack has been observed. This effect occurs only when the lens is focused near the upstream edge of the target. (3) The target density depletion study in powdered rhenium showed an apparent yield reduction on the time scale of a single proton pulse, accompanied by release of airborne radioactive material.
Measurement of Escaping Ions in the Fermilab Antiproton Accumulator
Positively charged ions trapped in the negatively charged beam of the Fermilab antiproton accumulator pose a limit to beam stability and density. To better understand the dynamics and the consequences of the beam-ion interaction, they have built and installed a low energy ion detector and energy analyzer in the Fermilab accumulator. This analyzer is capable of energy analysis of the escaping ions using a probe with energy retarding grids and may also be scanned in the pitch angle of the escaping ions. Measurements have been made in both longitudinal and transverse planes under a variety of machine operating conditions. The experimental measurement results are presented together with attempts to model the ion dynamics and explain observations.