Search Results

You are looking at 31 - 40 of 65 items for

  • Author or Editor: S. Landsberger x
  • All content x
Clear All Modify Search

Abstract  

We have developed a PC based program for neutron activation data analysis using the FORTRAN and C languages. The routines are based on creating files associated with conventional ORTEC hardware and output software. The main features of the program include radionuclide identification, and the use of semi-automatic integration or the peak fitting SAMPO routine. Other developments are hard and soft copy records for detailed sample identification and particular irradiation, decay and counting procedures. Flux variations, high deadtime corrections, counting geometries, spectral and nuclear interferences, as well as uranium fission interferences are also automatically accounted for. The data output includes concentration values in %, ppm, g or ppb units with associated errors, while detection limits for each individual sample are indicated. Further data output can easily be generated which can be imported to most spreadsheet programs for various statistical uses. A future implementation to the program will include batch-file processing and automated self-absorption calculations for geological samples.

Restricted access

Abstract  

We have developed a highly automated program for the analysis of data from neutron activation analysis (NAA). Spectral analysis is done using almost any common MCA employing regions of interest or peak-fitting routine of the user's choice. A wide variety of data entry possibilities is available, from fully manual data entry to an automatic mode where the user enters all necessary data in a tabular format and the computer calculated the results. The resulting data can be automatically imported into a LOTUS 1-2-3 compatible spreadsheet for statistical analysis. All of the features of previous versions of NADA have been retained. These include a variety of methods for dead-time correction, correction of spectral and nuclear interferences, and a complete, concise hard-copy output. Future improvements include a routine which will automatically select regions-of-interest for spectra in ORTEC Maestro, thus reducing the processing time needed.

Restricted access

Abstract  

Open front hoods are routinely used to mitigate a worker’s inhalation hazard. However, it has been shown that these hoods leak contaminates, especially when a worker is performing work in the hood. Quantitative measurement performed in the past does not reflect actually working conditions, but instead tends to conservatively bias the measurement by placing the sampler inside the hood or forcing the air-stream out of the hood toward the sampler. In order to accurately measure the amount of material routinely leaking from an open front hood, an air sampler was positioned in front of the hood opening and samples were taken while a routine sample digestion process was done. The digestion process involved the heating of a surrogate mixture to dryness. Samples were taken with and without a worker present during the digestion process. The samples were then analyzed at the University of Texas using neutron activation analysis. The detection level using this method was low enough to measure the amount of aerosol escaping the hood. Based on these measurements, the capture efficiency of open front hoods for PuO2 is 84%.

Restricted access

Summary  

Potassium is an extremely important major element to the human body. Potassium is made up of three isotopes with abundances of 39K at 93.1%, 40K at 0.0118% and 41K at 6.88%. It is also very well known that 40K with its 1.3 . 109 years half-life is a major naturally occurring isotope in the body and food. The usual way to determine total 40K is to measure the single 1460.8 keV photon from beta-decay. However, this procedure requires a significant amount of sample and typical counting periods of at least a day in well-shielded germanium counting system. Another approach is to determine total potassium via neutron activation analysis using the well known 41K(n,g)42K (T 1/2 = 12.8 h) reaction and then evaluate 40K using the usual activity equation A = l N. In our laboratory we have effectively used epithermal neutron activation analysis and Compton suppression to determine potassium in air filters and other geological material. Upwards to 10-15 samples can be analyzed in one day using only gram quantities of material. In such way one can increase the output of determining 40K by at least one order of magnitude. Results of a detailed investigation optimization of the methodology, quality control and detection limits will be presented for reference material and various food samples.

Restricted access

Summary  

In this paper, a description is made of the survey that was undertaken, for the first time, about the situation of radiochemistry activities in the Region of Latin America, comprising twenty countries from South America, Central America and the Caribbean. It became clear from this study that very strong differences exist between the countries and that most of the nuclear facilities in operation, such as nuclear reactors, hot cells, radiochemical laboratories and cyclotrons are concentrated in seven countries, accompanied by research and educational activities. A detailed study of the situation and trends in the Latin American countries is presented, as regards teaching and other activities related to Radiochemistry, as well as a series of suggestions for preservation of knowledge in the field.

Restricted access

Summary  

{\rtf1\ansi\ansicpg1250\deff0\deflang1038\deflangfe1038\deftab708{\fonttbl{\f0\froman\fprq2\fcharset238{\*\fname Times New Roman;}Times New Roman CE;}} \viewkind4\uc1\pard\f0\fs24 We have developed a method for analyzing neutron activated sample data by using Microsoft Excel as the analysis engine. A simple technique for inputting data is based on report files generated by Canberra’s Genie-2000 spectroscopy system but could be easily modified to support other vendors having report formats with consistent text placement. A batch program handles operating an automatic sample changer, acquiring the data, and analyzing the spectrum to create a report of the peak locations and net area. The entire report is then transferred to within an Excel spreadsheet as the source data for neutron activation analysis. Unique Excel templates have been designed, for example, to accommodate short-lived and long-lived isotopes. This process provides us with a largely integrated solution to NAA while providing the results in an industry standard spreadsheet format. This software is ideally suited for teaching and training purposes. \par }

Restricted access

Abstract  

Phosphates, naturally containing trace amounts of uranium, were examined using direct γ-ray spectrometry. Both normal and Compton-suppressed counting modes were utilized. The 1001 keV photo peak of the second daughter of 238U was chosen because of its isolation from other, potentially interfering peaks. The findings suggest that with the aid of Compton suppression, it is possible to quantify low uranium levels in phosphates using samples sizes of order 10 grams within an accuracy of 5%. The uranium content was determined in several sample types and was found to range from 60±4 to 70±8 μg/g, depending on the sample composition. This investigation also considered the effects of sample size, counting time, and counting technique as sources of precision maximization. This work has shown that only a small amount of phosphate is needed to determine the constituent concentration, instead of the standard several hundred grams of material.

Restricted access

Abstract  

Thermal and epithermal neutron activation analysis techniques were used to analyze 27 Teflon air filters which were exposed to ambient air in Lisbon, Portugal, in February 2007. Tin was detected which is strongly suggestive of an anthropogenic source. Arsenic, antimony and copper were shown to be highly correlated, which is also suggestive of anthropogenic pollution. Trace element analysis of short- and medium-lived isotopes was performed yielding concentration information of various elements. Analytical sensitivities were enhanced using a Compton suppression system. Enrichment factor analysis shows that arsenic, tin, zinc, copper and antimony are at elevated concentrations in the Lisbon atmosphere.

Restricted access

Abstract  

Fifty air filters with fine and coarse fractions were prepared from NIST 2710 contaminated soil. Eighteen pairs were made and sent to laboratories of the Coordinated Research Program (CRP) on Applied Research on Air Pollution Using Nuclear-Related Analytical Techniques for elemental determination. The results of this intercomparison are discussed in this paper.

Restricted access

Abstract  

We have used Compton suppression gamma ray counting to effectively measure 137Cs in undisturbed environmental samples weighing only one hundred grams of material. Our results have shown that Compton suppression is ideal in determining low levels (1–3 Bq/kg) of 137Cs in soil samples, while the Compton advantage is negligible for higher concentrations. Quality assurance and quality control experiments show that for samples weighing 100–200 grams, gamma-ray attenuation is significant (up to 10% difference) when analyzing different soil compositions.

Restricted access