bluuebunny/crossref_metadata_2025 huggingface dataset:
Light-Ion Irradiation Creep and Hardening of Model Ferritic Alloys
Authors: Henager CH , Simonen EP
Published: December 2008

Light-ion irradiation creep testing was combined with microhardness testing to study changes in creep strength of two model ferritic alloys. Creep enhancement followed by radiation hardening was observed for both alloys. Post-irradiation creep rates and post-irradiation microhardness data confirm that significant radiation hardening occurred due to the 673 K deuteron bombardment of 0.05 displacements per atom (dpa). Measured rapid creep rates were consistent with a climb-glide creep model developed for pure Ni after dislocation bias factors were reduced by a factor of five to account for the body centered cubic (bcc) structure. This was attributed to the relative insensitivity of climb-glide creep to the interstitial bias, and to the fact that the small dislocation loops were unfaulted in the ferritic alloy but were initially faulted loops in the Ni. Electron microscopy revealed that a high density of small dislocation loops were formed during the irradiation. Microhardness testing results were consistent with irradiation hardening due to dislocation loops, as were the creep results.
Effects of Microstructure and Thermal Aging on Neutron Irradiation Embrittlement of 2¼Cr-1Mo Steel for a Nuclear Pressure Vessel
Authors: Suzuki M , Fukaya K , Kodaira T , Oku T
Published: December 2008

Plate, weld, and heat-affected zone (HAZ) materials of 2¼Cr-1Mo steels, designated as ASTM A387 Grade 22 Cl.1, and Cl.2 were irradiated at around 400°C to a fluence of about 2 × 1018 n/cm2 (E > 1 MeV). A387 Grade 22 Cl.2 with bainite has a lower susceptibility to neutron irradiation embrittlement than A387 Grade 22 Cl.1 with ferrite plus bainite. The anomalous ductile to brittle transition behavior of A387 Grade 22 Cl.2 was explained by taking into account the parameter ky, which is a constant in the Cottrell-Petch equation. It is concluded that there does not exist any strong interaction between thermal aging embrittlement and neutron irradiation embrittlement.
Tensile Properties of Several 800 MeV Proton-Irradiated bcc Metals and Alloys
Authors: Brown RD , Wechsler MS , Tschalär C
Published: December 2008

A spallation neutron source for the 600-MeV proton accelerator facility at the Swiss Institute for Nuclear Research (SIN) consists of a vertical cylinder filled with molten Pb-Bi. The proton beam enters the cylinder, passing upward through a window in contact with the Pb-Bi eutectic liquid that must retain reasonable strength and ductility upon irradiation at about 673 K to fluence of about 1 × 1025 protons/m2.

Investigations are underway at the 800-MeV proton accelerator at the Los Alamos Meson Physics Facility (LAMPF) to test the performance of candidate SIN window materials under appropriate conditions of temperature, irradiation, and environment. Based on considerations of chemical compatibility with molten Pb-Bi, as well as interest in identifying fundamental radiation damage mechanisms, Fe, Ta, Fe-2.25Cr-1Mo, and Fe-12Cr-1Mo (HT-9) were chosen as candidate materials.

Sheet tensile samples, 0.5-mm thick, of the four materials were fabricated and heat treated. The samples were sealed inside capsules containing Pb-Bi and were proton-irradiated at LAMPF to two fluences, 4.8 and 54 × 1023 p/m2. The beam current was approximately equal to the 1 mA anticipated for the upgraded SIN accelerator. The power deposited by the proton beam in the capsules was sufficient to maintain sample temperatures of about 673 K. Post-irradiation tensile tests were conducted at room temperature at a strain rate of 9 × 10−4s−1. The yield and ultimate strengths increased upon irradiation in all materials, while the ductility decreased, as indicated by the uniform strain. The pure metals, Ta and Fe, exhibited the greatest radiation hardening and embrittlement. The HT-9 alloy showed the smallest changes in strength and ductility.

The increase in strength following irradiation is discussed in terms of a dispersed-barrier hardening model, for which the barrier sizes and formation cross sections are calculated.
Comparison of Irradiation-Induced Transition Temperature Increases from Notch Ductility and Fracture Toughness Tests
Authors: Hiser AL
Published: December 2008

Reactor pressure vessel (RPV) surveillance capsules contain Charpy-V notch ductility Cv specimens, but many do not contain fracture toughness specimens; accordingly, the radiation-induced shift (increase) in the brittle-to-ductile transition region ΔT is based upon the ΔT determined from Cv tests. Since the American Society of Mechanical Engineers (ASME) KIc and KIR reference fracture toughness curves are shifted by the ΔT from Cv, assurance that this ΔT does not underestimate ΔT associated with the actual irradiated fracture toughness is required to provide confidence that safety margins do not fall below assumed levels.

To assess this behavior, comparisons of ΔTs defined by elastic-plastic fracture toughness and Cv tests have been made using data from RPV base and weld metals in which irradiations were made under test reactor conditions. Using “as-measured” fracture toughness values KJc, average comparisons between ΔT(Cv) and ΔT(KJc) reveal that, on average, ΔT(Cv) tends to underestimate ΔT(KJc) for plates by 22°C and to overestimate ΔT(KJc) for welds by 5°C on average.

When the fracture toughness data are adjusted to account for specimen size using a “βIc correction,” the trends are the same as for KJc, with the underestimate for plates an average of 10°C and the overestimate for welds 11°C on average.

Comparison of ΔTs at various index levels implies that the Cv curve for irradiated material tends to be shallower than that for unirradiated material. However, the shape of the KJc curve for irradiated and unirradiated material is the same, but the Kβc curve for irradiated material is steeper than that for unirradiated material.
Comparison of the Effect of Power and Test Reactor Irradiations on the Fracture Properties of Submerged-Arc Welds
Authors: Lowe AL , Pavinich WA
Published: December 2008

The Babcock & Wilcox (B&W) Owners Group Integrated Reactor Vessel Surveillance Program contained two irradiation phases in addition to the plant specific surveillance programs. One phase provided materials for a short-term (test reactor) study of the effects of neutron irradiation on high-copper low-upper-shelf weld metals as a part of the Heavy Section Steel Technology (HSST) Program. This phase was followed with an irradiation study using the long-term (power reactor) radiation source.

These studies were distinguished from other irradiation studies in that production weld metals were used. The chemical composition of the weld metals were similar except for the copper content which ranged from 0.21 to 0.42%. The specimens used for mechanical properties evaluation consisted of tension, Charpy V-notch, and compact fracture specimens.

The power reactor irradiations were conducted in B&W Owner's Group host reactors. The fluence attained in both the test and power reactors was approximately 7 × 1018 neutrons (n)/cm2. These two neutron sources provide a means for evaluating the influence of neutron environment on material damage.

The Charpy impact toughness is evaluated by the 41 J (30 ft · lb) shift and decrease in upper-shelf energy. The tension data is evaluated using the standard mechanical properties. The fracture toughness data obtained from compact fracture specimens, using J-R elastic-plastic fracture test techniques, was evaluated.

These comparisons indicate that test reactor irradiated yield strength data and fracture toughness data is equivalent to that of a power reactor. A comparison of Charpy properties indicates that the data may be sensitive to parameters other than neutron environments.
Investigation of Neutron Irradiated Reactor Pressure Vessel Steel by Positron Annihilation and Electron Microscopy
Authors: Sastry Viswanathan B , Pachur D , Nandedkar RV
Published: December 2008

Positron lifetime, annihilation line shape, and electron microscopic measurements have been carried out on neutron irradiated pressure vessel steel (HSST Plate 03) meeting ASTM A533-B (Unified Numbering System [UNS] K12539). The positron annihilation parameters for specimens irradiated at 423 K to a dose of 1.5 × 1018 n/cm2 are found to decrease sharply during the post-irradiation annealing interval, 473 to 623 K. This correlates well with the stage seen in the recovery of Vickers hardness. On the basis of known evidence for carbon migration in α-iron and the interpretation of present results, enhancement and recovery of radiation hardening have been qualitatively understood in terms of formation and dissolution of carbon decorated vacancy complexes.
The Effect of Thermal Annealing on the Fracture Properties of a Submerged-Arc Weld Metal
Authors: Pavinich WA , Lowe AL
Published: December 2008

Charpy impact and compact fracture specimens were tested to determine the response of actual reactor vessel weld metals to the in-situ annealing cycle (454°C for 168 h) suggested by the Electric Power Research Institute (EPRI). This annealing cycle was developed to recover fracture properties lost as a result of radiation damage. The Linde 80 submerged-arc weld metals from the Babcock and Wilcox (B&W) Owners Group Integrated Reactor Vessel Material Surveillance Program were irradiated in power reactors. Resultant data are compared with the data from the EPRI sponsored in-situ annealing program. Comparison of the power reactor and test reactor data show similar responses to annealing. One-hundred percent recovery of the upper shelf and transition temperature was achieved after annealing for both reactor types. The EPRI J-R data showed only partial recovery with annealing. However, the B&W submerged-arc weld metals exhibited four responses to annealing: 1) complete recovery, 2) partial recovery, 3) negligible effect of either irradiation or annealing on the J-R fracture toughness, and 4) an increase in J-R fracture toughness to greater than the unirradiated value.

These varied responses indicate that the mechanism(s) of annealing recovery may be more complex than heretofore believed. A qualitative rationale, based on a defect cluster mechanism and a copper precipitation mechanism, is employed to explain the various annealing responses.
A Statistical Analysis of Fracture Toughness of Irradiated Low-Alloy Steel Plate and Welds
Authors: McGowan JJ , Nanstad RK
Published: December 2008

Studies of the effects of neutron irradiation on fracture toughness properties of steels have generally included a minimum number of tests for each material condition. The present study attempts to apply statistical analyses with multiple testing at selected temperatures to assess the accuracy and reliability of the results. Fracture toughness test specimens were irradiated in the Bulk Shielding Reactor at Oak Ridge National Laboratory at 288°C to target neutron fluences of 2 × 1023 n/m2 (>1 MeV). The materials were ASTM A533 Grade B Class 1 plate (HSST Plate 02) and four submerged-arc welds representing current nuclear pressure vessel fabrication practice. Both unirradiated and irradiated specimens were tested by two separate laboratories, and multiple tests were conducted at selected temperatures. Statistical analyses permitted determination of material and test variability and an interlaboratory comparison. Behavior in both the transition and upper-shelf regions was studied.
Fission Fragment Induced Hardening in Uranium Mononitride
Authors: Tamaki M , Matsui H , Kirihara T
Published: December 2008

Fission fragment-induced hardening of uranium mononitride (UN) was examined by the Knoop indentation technique. Measurements were done at a variety of indentation loads (25 to 500 g) and for specimens with various fission doses (2.7 × 1021 to 5.3 to 1024 f/m3). The hardness showed a gradual increase with fission dose until 1023 f/m3. After that, however, for irradiations in JRRs (a lower thermal neutron flux and low irradiation temperature), the hardness attained a maximum at around 5 × 1023 f/m3 followed by a successive decrease. By contrast, in the Japan Material Test Reactor (JMTR), in which the thermal neutron flux and irradiation temperature were 7 × 1017 n/m2s and 400°C, respectively, the hardness increased monotonically up to 5.3 × 1024 f/m3. In the thermal annealing process, on the other hand, the hardness exhibited two recovery steps at 650 and 950°C, to which two types of extended defects caused by fission fragment damage could be attributed. It is concluded here that dislocation loops and vacancy clusters contributed to the fission fragment-induced hardening of UN.
The Assessment of Seal Performance and Lifetime Prediction in a Nuclear Environment
Authors: Burnay SG , Hitchon JW
Published: December 2008

A method of seal lifetime prediction has been developed using time-temperature superposition to detemine the functional relationships between compression set and the accelerating variables, that is, temperature, dose, and dose rate. Using this technique, seal lifetimes under service conditions can be predicted even when the elastomer exhibits dose rate effects or synergism between radiation and temperature.
Irradiation Effects in KAPTON Polyimide Film from 14-MeV Neutrons and Cobalt-60 Gamma Rays
Authors: Abe K , Logan CM , Saneyoshi K , Clinard FW
Published: December 2008

Polyimide films are insulating plastic materials that are useful over a wide temperature range and the most radiation resistant of the polymers. In this paper, mechanical property changes of the polyimide film, KAPTON, caused separately by 14-MeV neutrons and by cobalt-60 gamma rays are examined in detail. Miniature tension specimens of 3-mil-thick film were irradiated at Rotating Target Neutron Source-II and at the Cobalt-60 Pool of Lawrence Livermore National Laboratory at room temperature to a maximum neutron fluence of 1.6 × 1022 n/m2 and a maximum gamma dose of 8.6 × 107 Gy, respectively. Neutron fluences greater than 1 × 1021 n/m2 and gamma dose greater than 2.2 × 107 Gy caused a reduction in total elongation of the film. At our highest tested neutron fluence of 1.6 × 1022 n/m2, the elongation dropped to less than one-fifth and the fracture stress dropped to one-third of the unirradiated value. It was found that 14-MeV neutrons were about eight times more effective than cobalt-60 gamma rays in producing mechanical property changes when compared on the basis of absorbed dose. Color changes induced by irradiation were also examined.
The Low-Temperature Neutron Irradiation Facility at ORNL
Authors: Kerchner HR , Coltman RR , Klabunde CE , Young FW
Published: December 2008

The Low-Temperature Neutron Irradiation Facility (LTNIF) is now operating at Oak Ridge National Laboratory. The facility provides high radiation intensities and special environmental and testing conditions for qualified experiments at no cost to users. A general description and major specifications of the LTNIF are presented along with the results of performance tests. In addition, the hardware and other considerations required to perform experiments in the LTNIF are described.
Comparison of Calculated Integral Values Using Measured and Calculated Neutron Spectra for Fusion Neutronics Analyses
Authors: Sekimoto H
Published: December 2008

The kerma heat production density, tritium production density, and dose in a lithiumfluoride pile with a deuterium-tritium neutron source were calculated with a data processing code, UFO, from the pulse height distribution of a miniature NE213 neutron spectrometer, and compared with the values calculated with a Monte Carlo code, MORSE-CV. Both of the UFO and MORSE-CV values agreed within the statistical error (less than 6%) of the MORSE-CV calculations, except for the outer-most point in the pile. The MORSE-CV values were slightly smaller than the UFO values for almost all cases, and this tendency increased with increasing distance from the neutron source.
Field Measurements for Air Quality in Office Buildings: A Three-Phased Approach to Diagnosing Building Performance Problems
Authors: Sterling EM , McIntyre ED , Collett CW , Meredith J , Sterling TD
Published: December 2008

This paper reports on a phased system of integrated measurements of ventilation and occupant complaints that is relatively inexpensive yet may lead to effective diagnosis of a building's indoor air quality (IAQ) problems.

1. Physical inspection of the building, surroundings, and ventilation system.

2. Use of standardized questionnaire to (1) compare distribution of responses to those obtained from buildings without increased occupant complaints, (2) determine major types of complaints, (3) inspect distribution of complaints by location in building, and (4) check for specific complaints that may indicate special sources of contaminants.

3. Use carbon dioxide (CO2) concentrations as an index of overall ventilation adequacy.

4. Use carbon monoxide (CO) distribution as an index for overall infiltration pattern of combustion byproducts.

5. Measure fresh air supply by location, during variation of mechanical system operation, using tracer gases, smoke pencils, and tests of actual functioning of the mechanical system.

6. Compare design specification of mechanical system with all observations.

Specific measurement techniques are illustrated through a case study.
Trace Gas Calibration Systems Using Permeation Devices
Authors: Mitchell GD
Published: December 2008

Permeation devices are used in a variety of dynamic gas dilution systems to prepare trace or ultra-trace mixtures of gases and vapors, generally for calibration purposes. The sources of errors in the use of a permeation device for calibration are associated with the reproducibility of flow measurements, temperature control, and the stability of the mass transport characteristics of the permeation device. Since the primary component of such a single or multi-stage trace gas calibration system is the permeation device, then it is befitting that a comprehensive study of the stability and transport properties be undertaken. This paper describes trace calibration systems and the factors that influence their operation. Also presented is COGAS, a dynamic dilution system that serves to calibrate both permeation devices and instruments. Such a system improves precision, reduces manpower requirements, and is versatile in its application.
Tunable Diode Laser Absorption Spectrometry for Ultra-Trace Measurement and Calibration of Atmospheric Constituents
Authors: Fried A , Sams R
Published: December 2008

There has been an ongoing quest for development of ever more sensitive and selective detection methods for studying various gas molecules of atmospheric importance. Both laboratory and ambient studies often require instrumentation capable of measuring ultratrace concentrations of such gases at, and below, the parts-per-billion range. Concurrently, accurate calibration standards, particularly those verified by independent techniques, are also required. The sensitive, selective, and versatile technique of infrared tunable diode laser absorption spectrometry is especially well suited for ultra-trace gas measurements and calibration standards verification. This combination, which is not shared by many other measurement techniques, results from the fact that diode laser spectrometers can be operated in an absolute mode as well as a more sensitive relative mode. In this paper, we discuss these capabilities and present specific examples for the measurement and calibration of ultra-trace levels of the important atmospheric gases nitrogen dioxide (NO2) and hydrochloric acid (HCl). In addition, we further discuss the application of tunable diode laser absorption spectrometry in the verification of NO2 permeation standards using the gas-phase titration reaction between nitric oxide (NO) and ozone (O3).
Laboratory and Field Validation of Solid Sorbent Samplers
Authors: Melcher RG
Published: December 2008

Solid sorbents are being used extensively to sample contaminants in air. This technique has proven valuable, not only to the industrial hygienist because the solid sorbent sampling tubes are easy to use and transport, but also to the analytical chemist who finds the analytical procedures straightforward and adaptable to a wide range of compounds. Since the integrity of the sample depends on the nature of the compound and sorbent and on the effects of a number of other parameters, it is important, if not essential, to obtain laboratory validation data before using the technique for obtaining monitoring data. Field spiking and conformation studies are also recommended to determine the effects of the specific plant atmosphere and other sampling variables under actual field conditions. This paper gives guidelines for designing both laboratory and field validation studies.
Detector Tubes
Authors: McKee ES , McConnaughey PW
Published: December 2008

The specificity of various detector tube systems is discussed. Some chemical reactions are given for various types of tubes to illustrate specific and nonspecific tubes. Most detector tube systems are not specific and this is one of the major disadvantages of using detector tubes. The accuracy of detector tubes is also discussed. Two methods of estimating accuracy are illustrated: (1) using MIL-STD 414, which is the method that the National Institute for Occupational Safety and Health (NIOSH) used for certifying detector tubes; and (2) the “DuPont” method, where the bias and precision (mean coefficient of variance) are estimated, and the overall accuracy is obtained from these values. Approximate accuracies of some detector systems are given. Finally, some advantages and disadvantages of detector tubes are listed.
Analysis of Asphalt-Containing Mixtures by Nuclear Magnetic Resonance
Authors: Irwin WP
Published: December 2008

An instrumental method using continuous-wave nuclear magnetic resonance (NMR) has been developed to determine, quickly and accurately, the asphalt content of asphalt-containing mixtures. The resonance signal of the asphalt, which is proportional to the total hydrogen content, through calibration, can be directly related to the asphalt content of asphalt-containing mixtures such as stabilized coating and asphalt-containing products such as saturated felt.

The NMR method has been compared with specific gravity, calcination, and extraction methods. The NMR method has been found to provide the most accurate measurement of stabilizer content and an equivalent measurement of the percent saturation of saturated felt. The typical analysis time is 5 to 15 min.
Measuring Adhesion and Cohesion of Rubberized Asphalts
Authors: Dutt O , Ashton HE , Laaly HO
Published: December 2008

Adhesion and cohesion are important aspects of performance of rubberized asphalts used for roofing and waterproofing. The conventional toughness-tenacity test performed with either the hemispherical or screw-type pull-head gives results that represent a combination of adhesive and cohesive forces. In many cases adhesion is lost, thus affecting peak load values. A new, tapering, grooved head designed to improve the adhesion aspect has been tested with four commercial samples of rubberized asphalt. The results are compared with those for other heads. Most tests were conducted at several speeds of loading to study the effect on toughness and tenacity values. In a second series of tests, the effect of adhesion was eliminated and only cohesion determined. Finally, straight pull-off adhesion tests and ductility tests were conducted on all samples. The results suggest that the present accepted test methods and numerical requirements for the related physical properties in standards for hot-applied rubberized asphalts should be reassessed.
Performance Testing of Fully Adhered, Polymer-Modified, Bituminous Roofing Membranes
Authors: Burnett EFP , Howson C
Published: December 2008

In cold climates, roofing membranes are subjected to at least two forms of critical loading:

1. In a fully adhered system, significant forces and deformations can be induced in the membrane by thermal deformation and movement at the joint in the substrate.

2. In severe climates, ice can form and bond to the top of the membrane. When the ice cracks, significant forces can be induced in the membrane.

The tension test is currently used as the standard test for the strength and elongation properties of most roof membrane materials. For fully adhered systems, such as modified bituminous membranes, the tension test is of only limited use since it does not simulate the actual in-place performance of the membrane or the constituent materials, especially for the load cases noted.

An alternative to the tension test is considered. A joint-bridging test procedure is developed that more closely models the loading to which a fully adhered roof system could be subjected.

The test specimen consists of a section of the roof system or membrane material that is fully adhered to a substrate. The substrate is separated into two sections. Each substrate section is gripped in the test machine jaw and these are separated at a constant rate. The force required to separate the substrate sections and the width of the joint opening between substrate sections are continuously measured.

It is evident that the joint-bridging test provides a better basis for understanding the behavior of fully adhered roof systems than does the tension test. The joint-bridging test simulates a realistic situation and it permits the study of reinforcement considerations.
Cold-Laid, Exposed, Two-Ply Modified Bitumen Roofing Systems
Authors: Schumacher W , Scherp E
Published: December 2008

Cold-applied glue shows convincing results of having long-term qualities for use in modified bitumen roofing systems. The product's most important features include the following advantages:

1. When using cold-applied glue, there is no heating-up time. Work can begin immediately, even under poor weather conditions.

2. Thanks to the strip application, there is a reduction of up to 70% in the amount of bonding material to be transported and used, in comparison with hot bitumen. Instead of 1.5 kg/m2, only 300 to 500 g/m2 is required and the uplift resistance is even higher than that for the 1.5 kg/m2 of hot bitumen.

3. Cold-applied glue eliminates the fire risk during application and, because of the small quantities employed, reduces the amount of combustible material. In the case of an interior fire, it does not form burning droplets.

4. Cold applied glue also bonds securely to cold, damp surfaces.

A self-adhesive, high-performance cap sheet represents a logical and consistent development of the cold-applied roofing system. The authors' company introduced this product onto the market in 1975 after exhaustive development work and tests. These roof sealing sheets are made of modified polymer bitumen with a solvent-free, cold, self-adhesive bonding layer covered with a removable siliconized protective foil. The roof cap sheet is made of bitumen sheeting, modified with styrol-butadiene-styrol (SBS) thermoplastic rubber. This fulfills the requirements of German Standard DIN 52132 for modified polymer bitumen roofing sheets.

Also made of a modified bitumen mass, the adhesive coating is matched to the modified top layer of the roof sealing sheet. It contains adhesive components and is absolutely free of solvents.

At the same time that the self-adhesive sheeting is rolled out, the protective foil is pulled off and the sheeting is pressed down in place. The nongranulated sticky edges at the side of the top of the sheet ensure a perfect seam.

In the case of renovation work or new construction, a roof system can be installed with one or two layers. Over the past ten years, this system of cold glue (roll-form) insulation and a cold self-adhesive cap sheet has continued to demonstrate its economy, secureness, and ease of use in an increasing number of installations in many countries throughout the world.
Low Temperature and Low Pressure Silicon Epitaxy by Plasma-Enhanced CVD
Authors: Reif R
Published: December 2008

This paper reviews the most recent results obtained using a very low pressure, plasma enhanced chemical vapor deposition technique for low temperature (650–800°C) silicon epitaxy. Initial results on autodoping studies and on p-n junctions and MOS transistors fabricated in these films are briefly discussed.
Thin Silicon Epitaxial Films Deposited at Low Temperatures
Authors: Chang H-R , Rosczak JS
Published: December 2008

Specular epitaxial silicon layers have been successfully deposited on 3-inch wafers at 825°C using an atmospheric pressure chemical vapor deposition process. No plasma or high temperature etching is involved in this process. Predeposition cleaning of the substrate surface is the key to achieve epitaxial growth at this low temperature. Quantitative characterization of the low-temperature epitaxy quality has been performed by X-ray diffraction, UV reflectance, Hall mobility measurement, and diode breakdown measurement. All test results demonstrated that an epitaxy comparable to that of high temperature epitaxy has been achieved. This low temperature epitaxy process greatly reduces the out-diffusion and autodoping, thus leading to significant improvement in device dimension control.
Effect of a Shallow Xenon Implantation on a Profile Measured by Spreading Resistance
Authors: Lora-Tamayo E , Du Port de Pontcharra J , Bruel M
Published: December 2008

Shallow xenon ion implantations were performed into silicon wafers previously doped by BF2+ implantation and subsequent annealing. The major extended changes in the spreading resistance profile of the P-type doping, arising from the shallow xenon implantations, are presented here. A possible explanation of this effect on the electrical profile, based on “carrier spilling” described and analyzed by S.M. Hu (5) is presented.
Measurements of Cross-Contamination Levels Produced by Ion Implanters
Authors: Larson LA , Kirby BJ
Published: December 2008

The contamination of implants by other species previously used in the same machine has been shown to be of significant concern for high-dose implants. This paper reports the results of a survey of the contamination levels extant in high-volume production implanters. Two classes of machines are represented. The first includes machines where wafer holders have been dedicated to a particular species. The second is machines where no precautions regarding cross-contamination have been taken. The machines have different production histories, especially for different species, and it is felt that the range of contamination levels reported is typical of what might be seen.
Monte Carlo Simulation of Plasma Etch Emission Endpoint
Authors: Bawolek EJ
Published: December 2008

As dry etch requirements become more severe, the trend is toward greater automation of the etch process. Automated endpoint detection is desireable to prevent excessive substrate damage and to increase etch reproduceability. The challenge in designing an automated endpoint detector is to provide a unit with sufficient intelligence to correctly recognize etch completion despite wafer non-uniformity and wafer to wafer variations. In this paper a simple, easy to implement simulation program based on Monte Carlo techniques is described which can be used to study the effect of wafer thickness and etch rate uniformity on the emission endpoint transition. A version of the program which incorporates loading effects is also demonstrated. The loading effect is shown to increase the abruptness of the endpoint transition. The simulation is compared with actual emission data for nitride and polysilicon etching in a commercial single wafer plasma etcher.
Profile Control of Plasma Etched Polysilicon Using Implant Doping
Authors: Abraham T , Theriault R
Published: December 2008

The effect of implant doping using phosphorus on the edge profiles of plasma-etched polysilicon was investigated. Unique rounded profiles were obtained with as-implanted samples. The profile curvature showed a strong dependence on the fluorine to chlorine ratio in the etch process. There was good correlation between the lateral etch rate variation across the polysilicon thickness and the doping profile. Electrical line width measurements and SEM micrographs indicated line width control of ±0.3 µm. The step coverage of as-deposited PSG was studied and enhanced coverage was observed as the edge profile curvature was increased.
Spreading Resistance Measurements — An Overview
Authors: Ehrstein JR
Published: December 2008

Spreading Resistance is the most versatile electrical technique for characterizing depth profiles in silicon. However, it is being increasingly challenged as an analytical method by shrinking device geometries. Consequently, refinement of such aspects as probe conditioning, sample preparation, and bevel angle measurement is needed, and traditional practice regarding calibration, algorithms, and profile interpretation must be reexamined. Based on examples drawn from the author's work, multilaboratory experiments, and recent literature to illustrate and discuss these topics, this paper attempts to summarize the current status of the measurement and its interpretation showing both strong points and apparent limitations.
Monte Carlo Calculation of Primary Kinematic Knock-on in Sims
Authors: Albers J
Published: December 2008

Secondary Ion Mass Spectrometry (SIMS) occupies a central position in atomic profiling of semiconductor device structures. One of the possibilities for distortion of the profiles is the phenomenon of knock-on where the incident sputtering ion transfers enough kinetic energy to the impurity atoms to push them deeper into the material before they can be sputtered and counted. The effects of sputtering and primary kinematic knock-on are investigated by means of a Monte Carlo code previously used to study ion implantation processes. In particular, the dependence of the primary kinematic knock-on on the mass and energy of the sputtering ion as well as the mass of the impurity atom are presented.
Analysis of Boron Profiles As Determined by Secondary Ion Mass Spectrometry, Spreading Resistance, and Process Modeling
Authors: Banke GW , Varahramyan K , Slusser GJ
Published: December 2008

A controlled experiment was performed for a comparative investigation of dopant profiles by secondary ion mass spectrometry (SIMS), spreading resistance (SR), and process modeling. Boron profiles of varying junction depth were considered. These profiles were generated by boron ion implantation in n-type silicon and by varying the subsequent drive-in times. There has been emphasis on the quantification of the day-to-day repeatability of both SIMS and SR techniques and their comparison to process modeling. SUPREM III process simulator was used to generate the modeling profiles. Statistical regression analysis techniques were utilized to characterize the measured dopant profiles. Although there are distinct differences between the profiles determined by SIMS, SR, and Process Modeling, some consistent relationships, as for junction depth, are shown.
Wafer Fab Automation, an Integral Part of the CAM Environment
Authors: Fiorletta CA , Lennard R , Harper JG
Published: December 2008

A flexible/wafer fab automation system has been developed to perform three basic functions; real time inventory control, material distribution throughout the fab; and automated loading of cassette-to-cassette process machines. This System consists of Automated Guided Vehicles (AGV's) for material transport, intelligent inventory control stations for management of material in queue, and a central computer control for System management and communications to the factory's CAM system.

The wafer fab of the future must have real time control of the manufacturing environment. This includes planning and scheduling of Work In Process, dynamic monitoring of material movement, interactive communications with the process machines and control of the automation system. This interaction permits Just In Time delivery of material to process equipment, and constant monitoring of lots in process. The benefits of an integrated system are lower manufacturing costs, lower inventory levels, shorter cycle time and higher yields.
Computer Integrated Manufacturing: The Realities and Hidden Costs of Automation
Authors: Ligeti MS
Published: December 2008

Automation of semiconductor manufacturing is no longer an option: technological and competitive pressures have made it a necessity. Increasing wafer sizes, the need for reduced particle contamination, increasingly complex process technologies, high capital equipment costs, and continuously declining selling prices are all major challenges for manufacturers. Devices must be produced not only with greater precision and higher quality, but with ongoing unit cost reductions as well. Automation appears to be the top candidate to help meet these challenges.

Automation, however, is not a magic wand. If not approached and managed carefully, it may become a very costly and disruptive exercise, instead of the beneficial one expected.

This paper covers some of the general problems and pitfalls of automation and highlights possible approaches to successful and cost effective solutions. The external and internal factors that determine the level of success also are discussed.

Finally, the recommended approach to automation and the responsibility for implementation will be described.
Uniformity in Compressive Strengths of Cement and Corresponding Concrete
Authors: Al-Badr HA , Kilpadikar AD
Published: December 2008

This article shows how ASTM Method for Evaluation of Cement Strength Uniformity from a Single Source (C 917-82) serves as a valuable tool in ascertaining the uniformity in the quality of cement produced. The results obtained on compressive strength tests of both cement and concrete—the cement being tested at Saudi Kuwaiti Cement Manufacturing Co. (SKC manufacturing quality control laboratory) and the concrete (using SKC cement) at the quality control laboratory of Saudi Arabian Vulcan Limited, a ready mix concrete plant—clearly indicate that there is very good uniformity in quality of cement produced at SKC's factory situated at Khursaniyah (in the Eastern Province of Saudi Arabia) with a capacity of 7000 MT/day of cement clinker due to the level of automation adopted in process control. Thus the article brings out that, in modern cement plants which are usually large in capacity, C917-82 is a suitable yardstick to assess whether the quality control procedures exercised are effective.
Atmospheric Corrosion and Development of a Stainless Steel Alloy Against Marine Environments
Authors: Ito S , Omata H , Murata T , Yabumoto Y
Published: December 2008

In order to investigate atmospheric corrosion of stainless steel, exposure tests were carried out at several locations. By analysis of the test results, it is considered that the distance from the shoreline can be the most significant factor affecting corrosion. Utilizing a developed evaluation method in laboratory and exposure tests, a new alloy of ferritic stainless steel as bright annealed surface was developed, based on the finding that amorphous silicon oxide film is more corrosion resistant against marine atmosphere. The proposed alloy is a type of highly purified 19% chromium ferritic stainless steel covered with a corrosion resistant bright annealed surface film.
Atmospheric Corrosion of Wrought Aluminum Alloys During a Ten-Year Period
Authors: Dean SW , Anthony WH
Published: December 2008

The deterioration in mechanical properties, mass loss, and the appearance of various forms of localized corrosion are documented for the exposure of a representative group of unstressed wrought aluminum alloys at three test sites over a ten-year period. Loss of ductility is the chief form of mechanical property damage observed. Among the forms of localized corrosion observed, intergranular corrosion, which led to partial sheet delamination or exfoliation, is the most damaging to the ductility of materials. Intergranular corrosion without a strong element of orientation in the wrought direction is less damaging, though more damaging than pitting without associated intergranular attack. A study of the effect of a sacrificial cladding layer indicated that loss of ductility can be completely eliminated when 7072 alloy is clad on 3004-H36 and 7178-T6 alloys, and 1230 alloy is clad on 2024-T3 alloy.
Barrier Coatings for the Protection of Steel and Aluminum Alloys in the Marine Atmosphere
Authors: Shaw BA , Aylor DM
Published: December 2008

The marine atmospheric corrosion resistance of a variety of metallic, ceramic, and metallic/ceramic coatings on aluminum and steel alloys is investigated to assess the long term protection capabilities of these barrier coatings. Results of 6 to 42 month exposures indicate that the following coatings provide the best marine atmospheric corrosion protection: thermal sprayed aluminum, zinc, zinc-aluminum pseudo alloy, aluminum oxide (Al2O3), and both zinc-based and aluminum-based metallic/ceramic coatings. The application of a low viscosity sealer to one of the ceramic coatings extends the protective capability of the coating.
A Second Generation Accelerated Atmospheric Corrosion Chamber
Authors: Schubert R
Published: December 2008

Accelerated atmospheric corrosion testing is an integral part of determining a component's resistance to gaseous attack and is needed to enhance resistance to gaseous attack and subsequent degradation. An acrylic box of 28-L volume with no exposed internal metallic components serves as the basic chamber. All gas lines and fittings are inert. Air with less than 5-ppb total pollutant and a dew point of less than −50°C provides the starting point for air doping. Chamber air is exchanged at a rate of once per minute without a turbulent directed airstream. Chamber temperature is controlled at 30°C and relative humidity (RH) is held at 70%. Current studies utilize 10-ppb hydrogen sulfide (H2S), 10-ppb chloride (Cl2) and 200 ppb nitrogen dioxide (NO2). This environment can be expanded, reduced, or substituted to include other gases such as acid vapors, ozone, and hydrogen peroxide. Pollutant gases are added to the moist make up air at the chamber entrance. All gas flows are controlled through electronic flow meters. National Bureau of Standards (NBS) traceable pollutant standards are regularly scheduled to calibrate monitors. Computer data acquisition of system parameters and control of the electronic flow meters provides for recording and adjustment of system parameters. Spatial pollutant uniformity around the chamber is insured by continuous monitoring of film growth on four copper coated, quartz crystal, thin film monitors. Results of initial data on gold and copper surfaces are presented.
The Universal Closed System for Liquids
Authors: Reynolds R
Published: December 2008

Many methods have been developed to control accidental contamination from liquid pesticides. They comprise “dry-break” or dripless connectors, and closed systems. The latter result from progressive legislation in California that restricts the open pouring of liquid pesticides.

The usual method for extracting pesticides from containers employs a removable, reusable probe, which is always contaminated. A new means to avoid contamination, the Universal Closed System, currently in development, uses a built-in disposable probe and valve in each container. The valve is dripless and is always closed unless activated by a unique extractor.

Field testing has shown the system to be safe, reproducible, and easy to use. Anticipated costs are at acceptable levels.
Farm Chemical Handling, Mixing, and Loading: Worker Safety and Environmental Concerns
Authors: Spurrier EC
Published: December 2008

The potential exposure resulting from the handling of farm chemicals, whether they be crop protection chemicals, nutrients, or other products, is of considerable importance to mixers, loaders, and applicators. Therefore there is a need to develop educational programs and mechanisms that can reduce this exposure to farm workers and to the environment. New farm worker protection regulations now being promulgated by the Environmental Protection Agency (EPA) justify new approaches, either in education, training, or development of new devices, or in procedures to minimize exposure to farm workers. Procedures for mitigating potential intrusion of nutrients and other chemicals into our surface and underground water resources must proceed. New ideas for reducing pesticide waste, reducing off-target movement (drift) from field applications, and developing fundamentally new concepts for chemical delivery to the target site are in order. Ideas for future research and development are discussed in this paper.
Nonionic Emulsifier Selection for Liquid Formulations to Obtain Compatibility with Solid Formulations
Authors: Keim WA
Published: December 2008

The major factors in a liquid/solid tank mix are (1) shear (mixing), (2) liquid (oil) formulation, (3) solid formulation, (4) ratio of liquid to solid in the tank-mix, and (5) active ingredient concentration in the carrier. A model that describes the rate of clabber formation is presented. A laboratory shaker test is used to generate test data that relate to field experience. An emulsifier component selection system is presented that involves an emulsifier knowledge base, candidate emulsifier systems, and tank-mix tests.
Methyl Esters of Fatty Acids as Pesticide Formulation and Application Aids
Authors: Hickey FL
Published: December 2008

Methyl esters of fatty acids were evaluated under laboratory conditions as cosolvents with soybean oil in pesticidal concentrates. Concentrates containing methyl esters showed reduced viscosities and pour points, and improved low-temperature solubility of the active ingredients, in comparison with concentrates employing soybean oil alone as the solvent. The relative benefits derived from the methyl ester varied with the structure and composition and with the pesticide being formulated. Emulsification of concentrates with and without methyl ester were compared, and were found to be equivalent. The viscosity and pour point of soybean oil alone were also found to be reduced by addition of methyl esters, suggesting the possibility of modifying these properties in applications such as crop oils and carrier oils. With some methyl esters, pour points of blends with soybean oil were lower than those of either the methyl ester or the soybean oil alone.
Development of SCEPTER® 1.5 ASU Formulation by Evaluation of Liquid Handling Properties
Authors: Keintz RC , Cross B , Kovacs G
Published: December 2008

SCEPTER® (common name: imazaquin) is a soybean selective herbicide which may be applied preplant incorporated, preemergence or postemergence. It is a member of a class of imidazolinone carboxylic acid herbicides discovered at American Cyanamid. SCEPTER is effective in most soybean regions of the United States; thus a robust formulation was required to maintain product homogeneity and integrity for storage in a wide range of climatic conditions.