Spark Source Mass Spectrography Research Articles

Computer program for precise evaluation of photographic plates in spark source mass spectrography

A program has been developed for the computer processing of electrical and photometric information required for the calculation of concentrations in spark source mass spectrography analysis. Based on the Hull semi-empirical relationship, it describes mathematically the calibration curve of each analyzed impurity. Its essential characteristics are: (1) correction for background, (2) correction of line width by a simple procedure, and (3) improvement of the precision of the measurements by simultaneous processing of the data relative to all the available isotopes of a single element. The theoretical aspect and the construction of the program are described. The experimental results given as examples, demonstrate the consistency of the procedure used. A brief comparison is established with other programs already published.

Analysis of Frozen Aqueous Solutions by Spark Source Mass Spectroscopy

Abstract Aqueous solutions can be analyzed directly in a spark source mass spectrograph by sparking to frozen drops of the sample solution. The minimum detection limit obtained from a 10−8 coulomb exposure is about 5 × 10−7 M solution concentration. Analytical precision of 8 to 30% relative is achieved through use of an internal standard added to the sample solution.

Multielement Analysis of Lunar Soil and Rocks

Results for multielement analysis of lunar soil and of seven rocks returned by Apollo 11 are presented. Sixty-six elements were determined with spark source mass spectrography and neutron activation. U. S. Geological Survey standard W-1 was used as a comparative stanadard. Results indicate an apparent uniformity of composition among the samples. Comparison with solar, meteoritic, and terrestrial abundances reveals depletiozt of volatile elements and enrichment of the rare earths titaniunm, zirconium, yttriuntm, and hafnium. Althouglh there is an overall similarity of the lunar material to basaltic achondrites amid basalts, the differences suggest detailed geochemical processes to the history of this material.

Study on Trace Analysis of Iron and Steel by Solid Mass Spectrography(II).On Precision, Relative Sensitivities and Analytical Results by Spark Source Mass Spectrograph

Reproducibility of ion intensities, relative senisitivities of various elements by a spark source mass spectrograph were invesigated, and iron and steel were analyzed. Reproducibilities in repeated measurements with constant source parameters were5-35% in coefficients of variation, and in separate measurements6-70%. It seemed that inhomogeneity of emulsion and samples did not attribute to the fluctuation. Relative sensitivities(platinum was unity)of various elements in low alloy steel, nickel base temperature alloy, copper alloy, aluminum alloy, zinc base die casting alloy and stainless steel were 0.17-24.6. They were not related with sample materials, but with heat of sublimation of each element, however, some problems in reproducibility and measuring condition remain to be resolved. More accurate determination was performed by calibrating with relative sensitivities in analysis of standard samples stainless steel. Commercial pure iron was analyzed, and comparison with results in wet chemical methods was tried. The limit of detection was0.005 Reproducibility of ion intensities, relative senisitivities of various elements by a spark source mass spectrograph were invesigated, and iron and steel were analyzed.Reproducibilities in repeated meas urements with constant source parameters were5-35%in coefficients of variation, and in separate measurements6-70%. It seemed that inhomogeneity of emulsion and samples did not attribute to the fluctuation.Relative sensitivities(platinum was unity)of various elements in low alloy steel, nickel base temperature alloy, copper alloy, aluminum alloy, zinc base die casting alloy and stainless steel were0.17-24.6.They were not related with sample materials, but with heat of sublimation of each element, however, some problems in reproducibility and measuring condition remain to be resolved. More accurate determination was performed by calibrating with relative sensitivities in analysis of standard samples stainless steel. Commercial pure iron was analyzed, and comparison with results in wet chemical methods was tried. The limit of detection was0.005-1ppm.

Routine Analysis of Metals Using a Spark Source Mass Spectrograph with Electrical Detection

An analytical method has been developed using a spark-source mass spectrograph for rapid, routine analysis. Using an electrical detection system and reproducible sample positioning, precisions of ±3% are attained under routine conditions with an accuracy of ±7% for several elements in the NBS 460 series of iron standards. Repetitive analyses of Ag in Cu demonstrate the method can analyze trace elements in metals with accuracies approaching ±2%. Details of the electrode positioning procedure and the analytical accuracy and precision of the technique are presented.

Mass Spectrometric Analysis of Solids

Comparing mass with other chemical analysis or instrumental analysis, it has the characteristics that enables to analyze almost all elements at the same time and very sensitively.Hereunder we describe about the developing history of r.f. spark source mass spectrography of solids which is used usually for analysis of impurities in iron and steel and also describe about ionization method, optical principle of ion focusing system, ion detecting method by photoplate etc.We explain, showing examples, about quantitative method calculating element concentration from exposure ratio of the same intensity measuring density by micro photometer and the qualitative analyzing method of composition element from mass spectrum.

Argon Concentration in Tungsten Films Deposited by dc Sputtering

The relative argon concentrations of dc-sputtered tungsten films were determined as a function of argon pressure, target-to-substrate voltage, substrate bias, and target-to-substrate distance, for both the diode and triode configurations. The results for films sputtered in the diode mode support Winters and Kay’s conclusions that the adsorption mechanism is due to entrapment of energetic neutral argon atoms. This model, however, does not. apply for all the argon content in films sputtered in the triode mode. An additional mechanism resulting in a greater entrapment of argon is proposed, namely, the entrapment of low energy argon ions originating from the supporting glow discharge. Measurements of the argon content of the tungsten films were determined using the rf spark-source mass spectrograph.

Analysis of radioactive metals by spark source mass spectrometry

A spark source mass spectrograph with photographic plate recording has been adapted for the analysis of plutonium and americium metals. Over seventy elements can be determined simultaneously in these metals. A comparison has been made between results obtained by mass spectrography and by conventional methods for impurity elements. The operations involved in handling radioactive materials in the mass spectrograph are also discussed.

An electrical detection system for a spark-source mass spectrograph

An electrical detection system has been developed which can be used with the high-frequency spark-source mass spectrograph. Details of the system are discussed and examples are given illustrating its advantages (rapidity and precision). One distinct advantage of electrical detection is that a constant volume of sample material is used for each impurity determination. The system can also be used to assess sample inhomogeneities.

Trace Analysis of Nonconducting Materials by a Spark Source Mass Spectrographic Auxiliary Electrode Method

Abstract The survey analysis capabilities of spark source mass spectrography have proved to be very important in the determination of very low concentrations of elements in nonconductors and semiconductors. Some of the methods devised for the special handling and sparking of the poor conductors have been reviewed by Guthrie1. In general, attempts to initiate and sustain a radio frequency spark between nonconductor self-electrodes require inconviently high spark voltages and considerable operator time and attention. Moreover, the low ion yields often characteristic of the nonconductor self-electrode spark compel exposure times commonly in excess of one hour for exposure levels requisite for the detection of impurities at 1 part-per-million concentrations.

Effects of Source Parameters on the Ion Intensity in a Triggered DC Spark Source Mass Spectrograph

A study was made of the influences of source parameters on ion intensities of various elements in a triggered DC spark source mass spectrometry, in order to apply the mass spectrometric method to the analysis of iron and steel. The experiment was carried out with a CEC#21-11OB type doublefocusing mass spectrograph equipped with a triggered DC spark source system. The source parameters observed are a sustain voltage(0∼800V), a triggered voltage(0∼3000V), a pulse length(0∼10μsec), a sustain capacitance(0.5∼20μF)and a frequency(10∼3000c/s). A sustain voltage is remarkably effective and ion intensities are abruptly varied in the voltage range between 400 and 600V, especially in an iron matrix sample. Generally, it was found that the amount of M2+ produced with this spark source system is greater than that produced with a R. F. spark source. The behavior of each element can be divided into two general classes: V, Cr, Mo and Nb are belong to one class, and As, Ga and Ag the other, whose characteristics depend on the second ionization potential of each element. Ion intensities are not varied by change of source parameters except a sustain voltage. A frequency is suitable as a variable parameter for regulating ion intensities. At the sustain voltage of 300V, the intensity ratio of M+/M2+ increases considerably in comparison with at that of 600V. Darkening curve gets out of parallel shape under a different source condition. Reproducibilities, on the whole, are 3∼30%for coefficients of variation which agree with those in the R. F. spark source system.

Determination of Argon in Thin Films by rf Spark-Source Mass Spectrography

Determination of Argon in Thin Films by rf Spark-Source Mass Spectrography

Sodium Analysis by Spark Source Mass Spectrography

Sodium Analysis by Spark Source Mass Spectrography

Use of a Spark Source Mass Spectrograph for the General Analysis of Geological Samples

For many years the spark source mass spectrograph has been used to analyze geological samples for trace impurities. The sensitivity variation between elements, a factor of two or three, has limited the use of this instrument in analyzing for major constituents. Experimental results show that these deviations are fairly constant for individual elements in samples of the same general composition. These deviations can be used as empirical correction factors to improve survey-type analyses of geological samples. Measurements of major constituents and trace impurities in several geological materials are reported.

Evaluation of the source of error in spark source mass spectrography

Evaluation of the source of error in spark source mass spectrography

The Spark Source Mass Spectrography Using Graphite Pressed Electrodes of Powdered Sample

The pressed electrode techniques using graphite perwder as a conducting suppdit material have been investigated to obtain favorable source conditions for quantitative analysis of powder samples by spark source mass spectrographic method. 1. Using the pressing tool which we have developed, a rod sufficiently strong to be clamped in the electrode holders could be formed from mixtures of graphite and sample in any ratio, so far as we tested with KCl, CdS, ZnCl2and GaAs. 2. The relative sensitivity, for example, of K to Cl in the graphite-KCl pressed electrodes was found strongly dependent on the spark gap width. However, comparatively reproducible sensitivity(relative standard deviation less than10per cent)could be obtained, provided that the spark gap could be easily kept at about100μ, with rf spark voltage at 40-60 KV, repetition rate at 100-300 per second and the graphite content larger than ca50per cent by weight. 3. A correction method for impurity elements contained in graphite powder used as support material was proposed.

Homogeneity Characterization of NBS Spectrometric Standards IV: Preparation and Microprobe Characterization of W-20% Mo Alloy Fabricated by Powder Metallurgical Methods

AbstractA significant problem of the National Bureau of Standards Standard Reference Materials program is the provision of standards suitable in homogeneity for use with microanalytical techniques such as the spark source mass spectrograph and the electron probe microanalyser. An interim approach to the problem has been the extended homogeneity characterization of selected existing standards. This paper describes the preparation and evaluation of the first NBS standard tested specifically from the beginning for application to electron probe microanalysers. The standard designated SRM 480 is a tungsten-20 weight percent molybdenum alloy prepared by a powder metallurgy process. Based on the results of about 1500 determinations for both tungsten and molybdenum by electron probe microanalysis, the material was found to be of high homogeneity at about the micrometer leve 1 of spatial re so lution. The coefficient of variation for molybdenum was 2.5% and that for tungsten 1.5%. Correction of relative intensity ratios to obtain concentrations is discussed in terms of input parameter uncertainties such as mass absorption coefficients, and electron backscatter factors. The result of studies for atomic number correction and effects on operating voltage on the microprobe absorption correction, will be given. It is concluded that SRM 480 should be a valuable addition to any microprobe laboratory doing quantitative analyses.

Use of an ion beam chopper for improved precision in spark source mass spectrography

Use of an ion beam chopper for improved precision in spark source mass spectrography

Determination of Nitrogen, Oxygen, and Hydrogen by Spark-Source Mass Spectrography

A procedure for the determination of nitrogen, oxygen, and hydrogen by spark-source mass spectrography is described. The reduction of instrument blank levels is an important consideration in this analysis. Factors which influence the blank level include vacuum, choice of sample etch, and baking of the source. A prespark of 100–300 nC is considered an integral part of the procedure, since it apparently removes the last traces of surface impurities. Blanks below 1 at. ppm have been observed. The procedure can also be applied for the determination of carbon.

Impurity analysis of alkali halides by mass spectrography

A technique for the trace impurity analysis of alkali halides has been developed using a radio-frequency spark source mass spectrograph. A large ratio between the singly charged metal ions to halide ions is observed due to their different ionic nature in the solid, the ionization process, or both. Under these conditions alkali and halogen impurities must be treated separately to obtain quantitative analysis.