Search Results

You are looking at 1 - 5 of 5 items for

  • Author or Editor: E. Montoya x
  • Refine by Access: All Content x
Clear All Modify Search

Abstract  

A method has been developed for the determination of cadmium in samples of food and biological materials using neutron activation analysis with radiochemical separation. The irradiated sample is digested in presence of cadmium carrier, with a nitric-perchloric mixture, evaporated to dryness, dissolved in 6M HCl and placed onto an ion exchange column loaded with Dowex 1-X8 resin in chloride form and conditioned with HCl 6M. The cadmium is retained in the resin. After a washing procedure with several portions of HCl of decreasing concentration, the cadmium is eluted with an ammonia-ammonium chloride buffer. The activity of 115mIn which is in equilibrium with 115Cd, is measured using a NaI(Tl) well type detector. The method has been evaluated by analyzing certified reference materials with cadmium concentrations covering a range of 0.020 to 200 mg.kg-1. The agreement of the results with the certified values is within 95%, which gives an indication of the sensitivity and accuracy of the proposed method.

Restricted access

Abstract  

The errors occurred when α, the parameter that accounts for the non-ideal behavior of the epithermal flux, are neglected, have been evaluated for the determination of twenty elements in biological materials, using. gold and sodium comparators, and zirconium to measure the thermal to epithermal flux ratio (f). Sodium allows the determination of 15 elements, and up to 18 elements can be determined in positions relatively well thermalized by the simultaneous use of gold and sodium comparators, in all the cases with errors ≦2%, when α is not considered. Results obtained for reference materials are presented.

Restricted access

Abstract  

The chemistry laboratory at the Peruvian Institute of Nuclear Energy (IPEN) has carried out a validation method for the samples of siliceous composition. At least seven variables affecting the robustness of the results were initially identified, which may interact simultaneously or individually. Conventional evaluation hereof would imply a massive number of analyses and a far more effective approach for assessment of the robustness for these effects was found in the Youden-Steiner test, which provides the necessary information by only eight analyses for each sample type. Three reference materials were used for evaluating the effects of variations in sample mass, irradiation duration, standard mass, neutron flux, decay time, counting time and counting distance.

Restricted access

Abstract  

Procedures for the determination of gold and silver in copper concentrates, using k 0 based neutron activation analysis, were developed and tested. The effects of gamma-ray self attenuation, neutron self-shielding and spectral interference were considered; precision, accuracy, and detection limits were studied by repeated analysis of copper concentrate internal reference materials. The analytical results have shown good precision and satisfactory accuracy in concordance with the detection limit and range of concentration.

Restricted access
Journal of Radioanalytical and Nuclear Chemistry
Authors:
L. Tandon
,
E. Hastings
,
J. Banar
,
J. Barnes
,
D. Beddingfield
,
D. Decker
,
J. Dyke
,
D. Farr
,
J. FitzPatrick
,
D. Gallimore
,
S. Garner
,
R. Gritzo
,
T. Hahn
,
G. Havrilla
,
B. Johnson
,
K. Kuhn
,
S. LaMont
,
D. Langner
,
C. Lewis
,
V. Majidi
,
P. Martinez
,
R. McCabe
,
S. Mecklenburg
,
D. Mercer
,
S. Meyers
,
V. Montoya
,
B. Patterson
,
R. Pereyra
,
D. Porterfield
,
J. Poths
,
D. Rademacher
,
C. Ruggiero
,
D. Schwartz
,
M. Scott
,
K. Spencer
,
R. Steiner
,
R. Villarreal
,
H. Volz
,
L. Walker
,
A. Wong
, and
C. Worley

Abstract  

The goal of nuclear forensics is to establish an unambiguous link between illicitly trafficked nuclear material and its origin. The Los Alamos National Laboratory (LANL) Nuclear Materials Signatures Program has implemented a graded “conduct of operations” type analysis flow path approach for determining the key nuclear, chemical, and physical signatures needed to identify the manufacturing process, intended use, and origin of interdicted nuclear material. This analysis flow path includes both destructive and non-destructive characterization techniques and has been exercized against different nuclear materials from LANL’s special nuclear materials archive. Results obtained from the case study will be presented to highlight analytical techniques that offer the critical attribution information.

Restricted access