T. R. Folsom

Variation of Cesium in the Ocean

Samples of sea water from several oceans and several depths were analyzed for natural cesium by flame photometry with precision of about 3.5 percent. The average of 16 assays of surface water from four oceans was 0.37 microgram per liter, somewhat less than the average previously reported. The average cesium concentration in samples taken between 500 and 1500 meters was about 14 percent higher than the surface average, suggesting that cesium may be transported downward by particulate material. Natural cesiumn is now somewhat easier to study in the ocean than radiocesium from fallout is, and information on one complements the other.

The concentrations of lithium, potassium, rubidium and cesium in some western American rivers and marine sediments

Abstract Lithium, potassium, rubidium and cesium in river water, suspended matter, and bottom sediments have been measured by a flame photometric method in samples from three western American river systems; concentrations in four marine sediments are given for comparison.

Precise Measurements of Cesium in the Ocean by Flame Emission Spectrometry

An automatic flame emission spectrometer has been developed for measuring traces of cesium in sea water samples with precision enough to demonstrate for the first time some significant concentration variations of this element in the ocean. Extremely reproducible comparisons of standard and unknown solutions are effected by a programmed sample changer employing a novel distribution valve. Temperature effects and influences of gas flow and draft fluctuation are suppressed by carrying out repeated comparisons of small portions of the extracted sample concentrate and of the standard, computing a concentration after each comparison and then averaging the results. Following each recording of the peak emission, the emission from a nearby spectral baseline also is automatically recorded by using a simple accessory added to the monochromator. A Plexiglas refractor slab mounted on an axis in front of the exit slit is rotated a few degrees by pulses from a programmer that is under command of a standard desktop calculator. Analyses of test samples containing about 0.3 µg of cesium replicated better than 0.3%. Surface cesium concentrations in the North Pacific were shown to vary less than 0.5%; however, typically deep water contained about 1.4% lower average concentrations than surface water.

Determination of alkali metals in blood from North Pacific albacore

Abstract 1. 1. Concentrations of alkali metals in blood of the North Pacific albacore were found to be, in μg/kg wet weight, 6.28 ± 1.66 for cesium, 2.65 ± 0.27 for sodium, 2.27 ± 0.28 for potassium, 443.2 ± 68.2 for rubidium, and 21.5 ± 0.7 for lithium. 2. 2. In liver the mean concentration for cesium was 26.75 ± 2.35, for sodium, 1.21 ± 0.10, and for potassium, 3.24 ± 0.42. 3. 3. In muscle the mean concentration for cesium was 37.10 ± 0.72, for sodium, 0.47 ± 0.05, and for potassium, 4.12 ±0.19. 4. 4. Total alkali content was found to be almost constant, while the individual alkali metals are shown to vary with respect to each other and with specimen wet weight.

FLAME PHOTOMETER SPECIALIZED FOR CESIUM.

A new photometer system is described that allows very small traces of an element, such as cesium, to be determined quantitatively with greater precision than previously possible with flame-emission spectra. For example, with the new system it is possible to replicate measurements of the cesium in quantities that are normally present in one liter of sea water (about 0.3 μg) with standard error less than two percent. Dilute cesium standard solutions can be compared significantly within a few parts per billion. This, apparently, has not been reported for any previous flame photometer. The system consists of two photomultiplier tubes observing a flame simultaneously, from the same aspect, but each having a different optical filter interposed. Use is made of a beam splitter and two interference filters, one filter passing only a narrow band centered at the 8521.1-Å line of cesium, the other filter passing a nearby band not containing much of this emission but rather passing a sample of the background of the flame that contributes much of the total statistical fluctuation. Signals from these two phototubes are compared by suitable differential circuits, and are continuously recorded. A specialized automatic sample-changing system was developed to provide for precise timing of the burning of the sample and the standard solutions and to carry out aspirator washings immediately following the burning of each sample. Finally, means are provided for continuously monitoring the aspiration rate by recording the brightness of the background (off-peak) signal independently.

Determination of Sodium and Potassium in Blood of Oceanic Fish by Emission Flame Spectrometry Using an Exponential Extrapolation with Multiple Standard Additions

A method is described for using multiple standard additions to determine sodium and potassium in samples of digested but unpurified blood of oceanic tuna fish whose flame emission responses are nonlinear. An exponential curve is fit in a rational manner to signals of the unknown and two or more spiked unknowns. Evidences are given suggesting that higher precision can be obtained in determination of these and similar elements in biological materials in a direct and simple manner.

Internal Energy Standardization of Multichannel Gamma Ray Spectra by Use of the 0.511 MeV Annihilation and 40K Peaks

A computer method is described for making after‐the‐fact adjustments for incorrect zero energy intercept and instrumental gain to experimental gamma ray pulse height spectra from NaI (Tl) scintillation spectrometers. The method makes use of the 0.511 MeV annihilation peak and 1.46 MeV 40K photopeak as internal energy reference standards, both of which peaks are available to NaI (Tl) scintillation detectors. The technique has been tested experimentally and appears to be of practical use for routine energy standardization of long counting time gamma ray spectra between 0.1 and 2.0 MeV.

Scale errors on oceanographic mercurial thermometers

Abstract Errors of more than 0·01°C due to the method used in engraving scales, may be common in oceanographic mercurial thermometers. In this study 8 non-reversing thermometers were used; out of these, the spacing between scribed lines was measured very accurately on 4 thermometers. Two of the thermometers had significant scale errors. New correction curves were made for the thermometers, using the scale measurement information. All the thermometers were then intercalibrated. It would appear that after this treatment any of these thermometers could be used as precision laboratory standards.

Computer Experience with Very Low-Level Gamma Analyses of Oceanographic Specimens

The techniques used to radioassay for fallout nuclides, in particular 137Cs, by gamma ray spectrometry are described. Details are given of the computer analysis of the spectra, of the internal energy standardization by the 0.511 MeV annihilation and 40K photopeaks, and of the use of smoothed background spectra. Agreement is shown between the computer method and a previously-used freehand graphical method.

Suppression of Evaporation Losses during Flame Photometry

When samples are analyzed in a flame photometer in a volatile solution, the effects of evaporation often cannot be neglected. This effect generally becomes more apparent whenever large numbers of samples are aspirated from an automatic sample changer. It has been found at Scripps Institution that evaporation losses can be greatly reduced by using slotted covers over the sample cups. The covers are pierced with slotted openings that admit the aspirator tip during aspiration but restrict the free escape of saturated vapor standing above the sample.