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%.
Authors:M. Sanchez, S. Landsberger, and J. Braisted
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 (T1/2 = 12.8 h) reaction and then evaluate 40K using the usual activity equation A = lN. 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.
Authors:S. Landsberger, D. J. O'Kelly, J. Braisted, and S. Panno
Halides, particularly Br- and Cl-, have been used as indicators of potential sources of Na+ and Cl- in surface water and groundwater with limited success. Contamination of groundwater and surface water by Na+ and Cl- is a common occurrence in growing urban areas and adversely affects municipal and private water supplies in Illinois and
other states, as well as vegetation in environmentally sensitive areas. Neutron activation analysis (NAA) can be effectively
used to determine these halogens, but often the elevated concentrations of sodium and chlorine in water samples can give rise
to very high detection limits for bromine and iodine due to elevated backgrounds from the activation process. We present a
detailed analytical scheme to determine Cl, Br and I in aqueous samples with widely varying Na and Cl concentrations using
epithermal NAA in conjunction with Compton suppression.
Authors:S. Landsberger, A. Massicotte, J. Braisted, and S. Gong
Arctic pollution is a problem of great concern, because its characteristics (transportation, assimilation into the environment,
etc.) are complex and not fully understood. Detection of elemental constituents has been undertaken through the use of neutron
activation analysis and Compton suppression (to lower the detection limits for radionuclides characteristic of mainly single
gamma-ray emission) to discover possible pollutant sources. The goal of this project was to perform a feasibility study to
determine the suitability of neutron activation analysis (NAA) to evaluate cadmium concentrations on air filters collected
in the Arctic.
Authors:Z. Lamari, S. Landsberger, J. Braisted, H. Neggache, and R. Larbi
Neutron activation analysis (INAA) has been applied to multielemental determination of eleven medicinal plants used to cure
the urinary tract diseases observed in Algeria. These plants include Androgena Citratus, Ceratonia Siliquata, Punica Granatum, Glyryrrhiza Glabra, Lausaunia Alba, Fragaria Vesca, Arbutus Unedol,
Hordeum Vulgaris, Papieteria Officinalis, Zea Mays L, and Davallia Seae. Concentrations of twenty elements Ba, Br, Ca, Cl, Co, Cu, Cr, Fe, I, Mn, Na, Mg, Rb, Sb, Se, Sc, Sr, Ti, V, and Zn have
been determined by short, and long irradiation times with a thermal and epithermal flux of 1.4·1012 n·cm−2·s−1 and 1.4·1011 n·cm−2·s−1, respectively. These analyses were performed in conjunction with Compton suppression. In almost herbs studied the Co, Cr,
Cu, Rb, Sb, Sc, Se and V are found to be present at trace levels, Br, Mn, and Zn at the minor level, and Ca, Cl, Fe, Mg and
Na are generally at the major level. The accuracy of the measurements has been evaluated by analyzing NIST-botanical references
Authors:M. Freitas, A. Pacheco, M. Bacchi, I. Dionísio, S. Landsberger, J. Braisted, and E. Fernandes
In 2003–2004, several food items were purchased from large commercial outlets in Coimbra, Portugal. Such items included meats
(chicken, pork, beef), eggs, rice, beans and vegetables (tomato, carrot, potato, cabbage, broccoli, lettuce). Elemental analysis
was carried out through INAA at the Technological and Nuclear Institute (ITN, Portugal), the Nuclear Energy Centre for Agriculture
(CENA, Brazil), and the Nuclear Engineering Teaching Lab of the University of Texas at Austin (NETL, USA). At the latter two,
INAA was also associated to Compton suppression. It can be concluded that by applying Compton suppression (1) the detection
limits for arsenic, copper and potassium improved; (2) the counting-statistics error for molybdenum diminished; and (3) the
long-lived zinc had its 1115-keV photopeak better defined. In general, the improvement sought by introducing Compton suppression
in foodstuff analysis was not significant. Lettuce, cabbage and chicken (liver, stomach, heart) are the richest diets in terms
of human nutrients.
Authors:S. Landsberger, A. Plionis, S. Biegalski, K. Foltz-Biegalski, E. Schneider, D. O’Kelly, J. Braisted, S. O’Kelly, and L. Welch
Over the last three years we have developed a very robust nuclear and radiochemistry program at The University of Texas at
Austin. The cornerstone of support was the DOE Radiochemistry Educational Award Program (REAP) that was awarded from 2002–2005.
A second award for the period of 2005–2008 was just received. This award has enabled us to support many educational activities
from vanguard classroom instruction, to laboratory enhancements, to research activities at the graduate and undergraduate
levels. Both traditional radiochemistry and advanced topics in nuclear instrumentation have been supported. Various DOE university
programs, national lab funding and IAEA fellowship grants, have allowed the Nuclear and Radiation Engineering Program at the
University of Texas to be at the forefront of nuclear and radiochemistry educational and research activities and help secure
the next generation of needed expertise.