Author: Publisher: ISBN: Category : Languages : en Pages :
Book Description
The Gamma-Ray multi-group analysis code MGA developed at Lawrence Livermore National Laboratory has been widely used in the area of gamma-ray non-destructive plutonium assay. This plutonium isotopic analysis code de-convolutes the complicated, 100-keV x-ray and gamma-ray region to obtain the ratio of Pu isotopes. Calibration of the detector efficiency is not required, but is determined intrinsically from the measured spectra. The code can either analyze low-energy gamma-ray spectrum taken using a high-resolution HPGe detector for energies below 300 keV, or analyze the low-energy spectrum combined with a high-energy spectrum (up to 1 MeV) in the two-detector analysis mode. In the latter case, the use of two detectors has been mandated by the conflicting requirements: excellent resolution at low energies (characteristic of small planar detectors) with good high-energy efficiency (characteristic of coaxial detectors). Usually, a high-energy spectrum taken using a coaxial Ge detector will not provide sufficient energy resolution for 100-keV plutonium isotopic analysis, while the small planar used at low energies has inadequate high-energy efficiency. An optimized-geometry ORTEC HPGe detector has been developed which combines good energy resolution at 100 keV combined with acceptable high-energy ((almost equal to) 1 MeV) efficiency in a single detector. It has been used to gather spectra of both low- and high-energy regions of plutonium spectra simultaneously, for analysis by MGA in the two-detector mode. Five Pu gamma-ray calibration standard sources were used in this study of this special detector.
Author: Publisher: ISBN: Category : Languages : en Pages :
Book Description
The Lawrence Livermore National Laboratory develops sophisticated gamma-ray analysis codes for isotopic determinations of nuclear materials based on the principles of the MultiGroup Analysis (MGA). MGA methodology has been upgraded and expanded and is now comprised of a suite of codes known as MGA++. A graphical user interface has also been developed for viewing the data and the fitting procedure. The code suite provides plutonium and uranium isotopic analysis for data collected with high-purity germanium planar and/or coaxial detector systems. The most recent addition to the MGA++ code suite, MGAHI, analyzes Pu data using higher-energy gamma rays (200 keV and higher) and is particularly useful for Pu samples that are enclosed in thick-walled containers. Additionally, the code suite can perform isotopic analysis of uranium spectra collected with cadmium-zinc-telluride (CZT) detectors. We are currently developing new codes with will integrate into the MGA++ suite. These will include Pu isotopic analysis capabilities for data collected with CZT detectors, and U isotopic analysis with high-purity germanium detectors, which utilizes only higher energy gamma rays. Future development of MGA++ will include a capability for isotopic analyses on mixtures of Pu and U.
Author: Publisher: ISBN: Category : Languages : en Pages : 11
Book Description
We describe the new capability of and.present measurement results from the PC/FRAM plutonium isotopic analysis code. This new code allows data acquisition from a single coaxial germanium detector and analysis over an energy range from 120 keV to above I MeV. For the first time we demonstrate a complete isotopic analysis using only gamma rays greater than 200 keV in energy. This new capability allows the measurement of the plutonium isotopic composition of items inside shielded or heavy-walled containers without having to remove the items from the container. This greatly enhances worker safety by reducing handling and the resultant radiation exposure. Another application allows international inspectors to verify the contents of items inside sealed, long-term storage containers that may not be opened for national security or treaty compliance reasons. We present measurement results for traditional planar germanium detectors as well as coaxial detectors measuring shielded and unshielded samples.
Author: Publisher: ISBN: Category : Languages : en Pages : 21
Book Description
In this module, we will use the Canberra InSpector-2000 Multichannel Analyzer with a high-purity germanium detector (HPGe) and the MGA isotopic anlysis software to assay a variety of plutonium samples. The module provides an understanding of the MGA method, its attributes and limitations. You will assess the system performance by measuring a range of materials similar to those you may assay in your work. During the final verification exercise, the results from MGA will be combined with the 240Pueff results from neutron coincidence or multiplicity counters so that measurements of the plutonium mass can be compared with the operator-declared (certified) values.
Author: Publisher: ISBN: Category : Languages : en Pages :
Book Description
A new method has been developed that achieves plutonium isotopic analysis precisions of better than 2% in counting times of only a few minutes, using only the 59- to 208-keV energy region of a spectrum. This breakthrough was achieved by developing a unique but highly accurate method for delineating the overall ''intrinsic'' efficiency curve, including the plutonium K-shell absorption discontinuity at 121 keV. Consequently, the measured 129- and 148-keV peak intensities can now be used to reliably determine the relative abundances of 239Pu and 241Pu. The intense 94- to 104-keV region is also analyzed, providing accurate data for the other isotopes of interest. 5 refs., 3 figs., 2 tabs.
Author: Publisher: ISBN: Category : Languages : en Pages : 8
Book Description
The IAEA has expressed a need for improved determination of gamma emitting nuclides in environmental samples collected during inspections of nuclear facilities and to use the MGA++ to determine U and Pu concentrations and isotopic compositions when those elements are present in relatively high concentrations. We are addressing the IAEA needs by evaluating the applicability of extended-range germanium detectors (ERG). In this paper we used 1g U isotopic standards and 100ug Pu liquid standards (1) to determine the performance of MGA++ on this special detector and (2) to estimate the amount of U and Pu necessary in the sample for determination of the isotopics via MGA++ within reasonable accuracy for a week of counting time using this ERG detector.
Author: Attila Vértes Publisher: Springer Science & Business Media ISBN: 144190719X Category : Science Languages : en Pages : 3693
Book Description
This revised and extended 6 volume handbook set is the most comprehensive and voluminous reference work of its kind in the field of nuclear chemistry. The Handbook set covers all of the chemical aspects of nuclear science starting from the physical basics and including such diverse areas as the chemistry of transactinides and exotic atoms as well as radioactive waste management and radiopharmaceutical chemistry relevant to nuclear medicine. The nuclear methods of the investigation of chemical structure also receive ample space and attention. The international team of authors consists of scores of world-renowned experts - nuclear chemists, radiopharmaceutical chemists and physicists - from Europe, USA, and Asia. The Handbook set is an invaluable reference for nuclear scientists, biologists, chemists, physicists, physicians practicing nuclear medicine, graduate students and teachers - virtually all who are involved in the chemical and radiopharmaceutical aspects of nuclear science. The Handbook set also provides further reading via the rich selection of references.
Author: J. Kerr Publisher: ISBN: Category : Languages : en Pages : 8
Book Description
The Multi-Group Analysis (MGA) code is widely used to determine nondestructively the relative isotopic abundances of plutonium by gamma-ray spectrometry. MGA users have expressed concern about the lack of flexibility and transparency in the code. Users often have to ask the code developers for modifications to the code to accommodate new measurement situations, such as additional peaks being present in the plutonium spectrum or expected peaks being absent. We are testing several new improvements to a prototype, general gamma-ray isotopic analysis tool with the intent of either revising or replacing the MGA code. These improvements will give the user the ability to modify, add, or delete the gamma- and x-ray energies and branching intensities used by the code in determining a more precise gain and in the determination of the relative detection efficiency. We have also fully integrated the determination of the relative isotopic abundances with the determination of the relative detection efficiency to provide a more accurate determination of the errors in the relative isotopic abundances. We provide details in this paper on these improvements and a comparison of results obtained with current versions of the MGA code.
Author: Publisher: ISBN: Category : Languages : en Pages :
Book Description
A gamma-ray spectrometry system has been developed for the Savannah River Plant that when coupled with calorimetry will allow a complete nondestructive assay of various plutonium product and waste materials contained in sealed cans. The computer-based system employs two germanium detectors to obtain spectral information that is analyzed in a unique fashion to obtain plutonium isotopic ratios.
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Author: Attila Vértes
Author: J. Kerr
Author: H. W. Kraner
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