Prompt gamma activation analysis (PGAA) and short-lived neutron activation analysis (NAA) applied to the characterization of legacy materials

Abstract

Without quality historical records that provide the compositions of legacy materials, the elemental and/or chemical characterization of such materials requires a manual analytical strategy that may expose the analyst to unknown toxicological hazards. In addition, much of the existing legacy inventory also incorporates radioactivity, and, although radiological composition may be determined by various nuclearanalytical methods, most importantly, gamma spectroscopy, current methods of chemical characterization still require direct sample manipulation, thereby presenting special problems with broad implications for both the analyst and the environment. Alternately, Prompt Gamma Activation Analysis (PGAA) provides a 'single-shot', in-situ, non-destructive method that provides a complete assay of all major entrained elemental constituents. Also, it generally obviates the need for sample handling and, thus, minimizes potential exposure to hazardous materials to both people and the environment. Additionally, neutron activation analysis (NAA) using short-lived activation products compliments PGAA, and is especially applicable when the NAA activation surpasses the PGAA in elemental sensitivity. The Lawrence Berkeley National Laboratory (LBNL) has developed a new miniature deuterium-deuterium (D+D) neutron generator that currently outputs ~ 4x10 9 neutrons/second. It is self-replenishing and low power and maximizes the use of monatomic D + ions that, in turn, maximizes neutron intensity. The LBNL PGAA system also uses a recently updated prompt gamma library database and Hypermet software to convert the raw PGAA spectral data to accurate and precise qualitative and quantitative elemental results. This paper 2 discusses the use of PGAA and short-lived NAA to characterize legacy materials at the Lawrence Berkeley National Laboratory (LBNL). IntroductionMuch of the legacy inventory at LBNL lacks quality historical records that satisfy the pertinent regulatory requirements for full characterization. Most of the inventoried materials also include one or more radioactive constituents, typically actinides, adding another dimension to the overall problem. The radioanalytical problem may generally be addressed by gamma spectroscopy. However, except for the primordial radioactivities with extremely long half-lives like U and Th, the presence of a visible mass of material is not generally attributable to the radioactive constituents but, instead, to the presence of stable carrier chemicals that must likewise be characterized. In the special case of the actinides, one may glean some information about the cationic moiety of the carrier substrate by alpha-induced x-ray fluorescence since most carrier compounds at LBNL have cationic entities of relatively high Z, thereby affording easier detection and evaluation of the fluorescence x-rays. However, for the anionic moiety, the respective Z values are usually much lower (e.g., fluorides, nitrates, oxides) and not generally amenable to fluorescence analysis. Therefore, to characterize stable...

Detection of Silver Jewelry with Orthogonal Double-Pulse LIBS

“…As the quality of our current life has soared, people's need for precious metal jewelry has increased dramatically and it is unquestionable that rapid and precise measurement of ingredients in precious metal jewelry benefits both the manufacturer and the customers. Common methods of metal jewelry measurement such as cupellation and potentiometric titration [1] contain two steps, that is, using chemical reagents to melt the samples and then determining the ingredients of jewelry with Ectrometry (AAS) [2], inductively coupled plasma atomic emission spectrometry (ICP-AES) [3], on activation analysis (NAA) [4] etc. Unfortunately, such techniques have disadvantages like lots of damage and consumption of samples, long analysis time, complicated operation etc.…”