Automation of analysis of airborne radionuclides observed in Canadian CTBT radiological monitoring networks using LINSSI

Linux System for Spectral Information (LINSSI¹) is a SQL database and established under Linux. Currently it is compatible with HPGe gammaspectra analysis software UniSampo, Shaman and Aatami. Based on this database and software, an automated analysis pipeline has been setup for Canadian CTBT radiological monitoring networks. This paper has investigated the performance of this pipeline in its capabilities and reliabilities of rapid small peak search, nuclide identification, and radionuclide activity concentration evaluation. Up to now, more than 80 thousand daily monitoring gamma-spectra have been automatically received and processed, the results have been stored in database. The pipeline nuclide detection limits is satisfied for environmental radiation monitoring and nuclear emergency preparedness.     

Performance of UniSampo-Shaman with gamma-ray spectra containing known traces of fission products

A set of 100 gamma-ray spectra with known traces of anthropogenic nuclides was utilized in the First System-Wide Performance Test (SPT1) of the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) in June 2005. The spectrum set was very realistic, since it is based on real measured spectra. Yet, the correct spectrum contents are known, when anthropogenic peaks with known areas have been synthesized into the spectra. This paper investigates the key performance indicators for the UniSampo-Shaman software package when applied to these spectra, concentrating on results from automated pipeline analysis. In summary, the UniSampo-Shaman performance is very satisfactory and fully in line with previous evaluations.     

Further development of a cosmic veto gamma-spectrometer

The Comprehensive Nuclear-Test-Ban Treaty (CTBT) is supported by a network of certified laboratories that perform high-resolution gamma-spectrometry on global air filter samples for the identification of 85 radionuclides. At the UK CTBT Radionuclide Laboratory (GBL15), a novel cosmic veto gamma-spectrometer has been developed to improve the sensitivity of measurements for treaty compliance. The system consists of plastic scintillation plates operated in time-stamp mode to detect coincident cosmic-ray interactions within an HPGe gamma-spectrometer. This provides a mean background reduction of 75.2 % with MDA improvements of 45.6 %. The CTBT requirement for a ¹⁴⁰Ba MDA is achievable after 1.5 days counting compared to 5–7 days using conventional systems. The system does not require dedicated coincidence electronics, and remains easily configurable with dual acquisition of unsuppressed and suppressed spectra. Performance has been significantly improved by complete processing of the cosmic-ray spectrum (0–25 MeV) combined with the Canberra Lynx? multi-channel analyser. The improved sensitivity has been demonstrated for a CTBT air filter sample collected after the Fukushima incident.     

Particulate matter, iron, and zinc in the atmosphere of a large Brazilian town

A Radionuclide Aerosol Sampler/Analyzer (RASA Mark 4) has been developed at PNNL for use in verifying the Comprehensive Nuclear Test Ban Treaty (CTBT). The RASA Mark 4 collects about 20,000 m³ of air per day on a 0.25 m² filter. This filter is automatically decayed for 24 hours, then advanced to a germanium detector for a 24 hour count. This system has been operated in Richland, WA for a limited period of time in a predeployment testing phase. The germanium-detector gamma-ray spectra have been analyzed by automatic spectral analysis codes to determine Minimum Detectable Concentrations (MDC) for a number of isotopes of interest. These MDC's have been compared to other atmospheric measurements in the field and in the laboratory.     

Recovery of plutonium from aqueous waste solutions using porous zirconia spherical particles

Based on the Linssi database and UniSampo/Shaman software, an automated analysis platform has been setup for the analysis of large amounts of gamma-spectra from the primary coolant monitoring systems of a CANDU reactor. Thus, a database inventory of gaseous and volatile fission products in the primary coolant of a CANDU reactor has been established. This database is comprised of 15,000 spectra of radioisotope analysis records. Records from the database inventory were retrieved by a specifically designed data-mining module and subjected to further analysis. Results from the analysis were subsequently used to identify the reactor coolant half-life of ¹³⁵Xe and ¹³³Xe, as well as the correlations of ¹³⁵Xe and ⁸⁸Kr activities.     

{\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 Automated analysis of off-line measured gamma-spectra using \scaps UniSampo\scaps0 gamma-ray spectrum analysis software including criterias for alarming systems \par }

Summary {\rtf1\ansi\ansicpg1250\deff0\deflang1038\deflangfe1038\deftab708{\fonttbl{\f0\froman\fprq2\fcharset238{\*\fname Times New Roman;}Times New Roman CE;}} \viewkind4\uc1\pard\lang2057\f0\fs24 In many laboratories the number of measured routine gamma-spectra can be significant and the labour work to review all the data is time consuming and expensive task. In many cases the routine sample does not normally contain radiation above a detectable level, and still the review of the spectra has to be performed. By introducing simple rules for emerging conditions, the review work can be significantly reduced. In one case the need to review the environmental measurement spectra was reduced to less than 1% compared to the original need, which in turn made the review personnel available for more useful functions. Using the \scaps UniSampo\scaps0 analysis system, the analysis results of spectra that are causing alarming conditions can be transmitted via e-mail to any address. Some systems are even equipped with the capability to forward these results to hand-portable telephones or pagers. This is a very practical solution for automated environmental monitoring, when the sample spectra are collected automatically and transmitted to central computer for further analysis. The paper describes how to set up an automatic analysis system, rules for the emerging conditions, technical solutions for an automated alarming system and a generic hypothesis test for the alarming system developed for \scaps UniSampo\scaps0 analysis software. \par }     

Background Reduction in IR Spectroscopy Using a Highly Scattering Filter

Abstract

There are many methods for measuring FT-IR spectra, for example, transmission, diffuse reflection, attenuated total reflection and so on. It is said that the transmission method is the most reliable method for qualitative and quantitative analysis of FT-IR spectra. The spectra of highly scattering samples such as coals or amorphous silicon powders measured by the transmission method, however, have large backgrounds with small relevant absorption peaks. Therefore, we investigated measuring methods for reducing the background itself. As a result, using a highly scattering 1R filter, we could clearly distinguish absorption peaks of amorphous silicon powders that were not found in IR spectrum measured by the normal transmission method. Our highly scattering filter is composed of fine Csl powders(<125?10 ^?6m) and fine KBr powders(<125?10^?6m).     

QA/QC Procedures,Validation Method,Traceability and Intercomparisons

Summary This work provides a systematic experimental approach to the demonstration of viability of instrumental neutron activation analysis (INAA) in chemical metrology. The practical approach was derived from a complete survey of uncertainty components that affect the INAA measurement process. These uncertainty components were classified by their magnitude and origin and subsequently minimized by appropriate steps in the INAA process. The process was tested with the INAA determination of Cr in SRM 1152A stainless steel; the Cr value is certified at 17.76&percnt; with an estimated uncertainty of 0.04&percnt; (0.23&percnt; relative). The INAA results from this procedure are in agreement with these specifications. Similar procedures have been applied to INAA multi-element determinations in a high temperature alloy. Agreement with available consensus values was demonstrated in the alloy. The guidelines on the determination of uncertainty were fully met, providing through INAA a valuable independent non-destructive tool in chemical measurements of metrological value such as required in the CCQM key comparisons.     

Compton suppressed gamma-spectrometry for Comprehensive Nuclear-Test-Ban Treaty samples

The Comprehensive Nuclear-Test-Ban Treaty (CTBT) is supported by a network of certified laboratories that perform high-resolution gamma-spectrometry on global air filter samples for the identification of 85 radionuclides. At the UK CTBT Radionuclide Laboratory (GBL15), the use of advanced Compton suppressed systems has been investigated to reduce the Compton continuum and improve detection sensitivity. Samples collected from the Philippines and during the Fukushima incident have been measured, demonstrating Compton continuum reductions of 28–59 % with suppression factors of 0.1–147.0. Detection sensitivity has been improved with typically 40 % lower MDAs, including ¹⁴⁰Ba to meet CTBT requirements. True coincidence summing effects have been considered, including the application to remove interferences by the elimination of gamma-rays in cascade. This has been demonstrated for the removal of ¹³⁴Cs allowing improved ¹³¹I measurement.     

Gamma ray spectrum smoothing by one-pass method

One-pass method with a piecewise cubic polynomial was used as a smoothing technique in gamma ray spectrum analysis. By this method, smoothed results of spectrum region is represented to several divided intervals each of which are fitted with a cubic polynomial calculated by least square technique, respectively. From the smoothing procedure of simulated photoelectric peaks and actual gamma ray spectra, following results were obtained. Photoelectric peaks which had more than 10 channels of FWHM (full width at half maximum) were fitted correctly and low count spectra of about 100 counts per channel could also be fitted smoothly. These smooth results can not easily be obtained by Savitzky's convolution technique. In conclusion, this one-pass method was found to be effective for gamma ray spectra, especially for photoelectric peaks of large FWHM and Compton region.     

Experience of the Finnish National Data Centre in radionuclide analysis for the Comprehensive Nuclear-Test-Ban Treaty

The Comprehensive Nuclear-Test-Ban Treaty (CTBT) is setting very specific requirements to processing of gamma-ray spectra. All the data collected in 80 radionuclide particulate stations are transmitted to the International Data Centre (IDC), where they are analyzed. National Data Centres (NDC) are the users of IDC services. The NDC's are responsible of giving technical information to National Authorities, who have thepolitical responsibility of the compliance to the treaty. The IDC analysis is not directly informing if a nuclear test has been conducted; it is just categorizing the spectra to help the NDC's to make their decision. An NDC must have a high confidence on the correctness of the radionuclide analyses the IDC, and the NDC itself, are performing. Special attention must be paid to Event Screening, where the NDC, among other things, needs a historical record of the measured data to be able to ignore the occasionally occurring fission products, for example. The amount of data produced is too large for an NDC to process interactively. Therefore, batch-processing capabilities are required from the NDC. The Finnish NDC is involved in evaluating of the IDC processing and software and it is also proposing a radionuclide processing solution for other NDC's, as well.     

Analysis of gamma-ray spectra from an aircraft-mounted array of high-resolution sensors

Gamma-ray spectra have been collected using the Environmental Radionuclide Sensor System.². Twenty aircraft-mounted, high-purity germanium sensors are utilized to collect high-resolution environmental spectra. Since time-over-target is limited for aerial surveys, one must often attempt to glean the maximum quantity of information from low-count spectra. The spectral data are collected in a time-stamped-list-mode, which time tags every gamma-ray. This allows a gamma-ray spectrum to be built without dilution for only the time-over-target. The analysis package utilizes photopeaks from natural background isotopes to autocalibrate and gain shift the individual spectra into a composite spectrum. The analysis software utilizes several unique techniques to robustly analyze low-count spectra. It carefully determines the spectral baseline, finds all the peaks which differ from the baseline by more than 4-standard deviations, uses a binary-search technique to fit Gaussian peaks, and utilizes a large library to identify peaks (including minor and escape peaks). Although in an aerial survey, the source geometry is often unknown or difficult to model, the software attempts to assign consistent source strengths to radionuclides. *** DIRECT SUPPORT *** A00E1009 00008     

Beryllium-7 activity at Comprehensive Nuclear-Test-Ban Treaty stations hosted by the United Kingdom

The Comprehensive Nuclear-Test-Ban Treaty (CTBT) is supported by a global network of monitoring stations that perform high-resolution gamma-spectrometry on air filter samples for the identification of radionuclides indicative of nuclear weapons tests and reactor incidents. These daily measurements have created an invaluable resource for understanding variations in natural background radioactivity, including the contribution of ⁷Be. Statistical analysis has been performed on ⁷Be data collected by CTBT stations hosted by the United Kingdom including at British Indian Ocean Territory (RN66), St Helena (RN67) and Tristan da Cunha (RN68) during 2005–2013. The results have been found to follow a lognormal distribution which implies that the ⁷Be activity is the multiplicative product of many small independent factors, such as meteorology, elevation, local station conditions, sample acquisition and analysis. This has the potential to identify discrepant measurements not attributable to the intrinsic variability of the distribution and indicative of station malfunction. Variations in ⁷Be activity have been considered on monthly, weekly and daily timescales and characterised using the geometric mean in accordance with the properties of the lognormal probability density function. Seasonal variations have been identified, with summer maxima and winter minima that are attributable to changes in mixing within the stratosphere and troposphere. Such fluctuations have been examined using the Fast Fourier Transform which may indicate variations associated with the 27 day solar cycle.     

Field testing of collection and measurement of radioxenon for the Comprehensive Test Ban Treaty

Pacific Northwest National Laboratory, with guidance and support from the U.S. Department of Energy's NN-20 Comprehensive Test Ban Treaty (CTBT) Research and Development program, has developed and demonstrated a fully automatic sampler-analyzer (ARSA) for the collection and quantitative measurement of the four xenon radionuclides,^131mXe (11.9 d),^133mXe (2.19 d),¹³³Xe (5.24 d), and¹³⁵Xe (9.10 h), in the atmosphere. These radionuclides are important signatures in monitoring for compliance to a CTBT, and may have applications in stack monitoring and other areas where xenon radionuclides are present. The activity ratios between certain of these radionuclides permit discrimination between radioxenon originating from nuclear detonations and that from nuclear reactor operations, nuclear fuel reprocessing, or from medical isotope production and usage. With the ARSA system, xenon is continuously and automatically separated from the atmosphere at flow rates of about 100 lpm by sorption-bed techniques. Samples collected in 8 hours are automatically analyzed by electron-photon coincidence spectrometry to provide detection sensitivities as low as 100 μBq/m³ of air. This sensitivity is about 10-fold better than achieved with reported laboratory-based procedures¹ for the short time collection intervals of interest. Gamma-ray energy spectra and gas analysis data are automatically collected.     

Evaluation of gamma-spectrometry equipment for on-site inspection

Journal of Radioanalytical and Nuclear Chemistry - An On-site Inspection (OSI) is an important component of the verification regime of the Comprehensive Nuclear-Test-Ban Treaty&nbsp;(CTBT),...     

Effect of Fe dopant on the physico-chemical and catalytic properties of vanadyl pyrophosphate catalysts

Summary 1&percnt; of Fe-doped and undoped vanadyl pyrophosphate catalysts were prepared via dihydrate method. The catalysts have been characterised by XRD, ICP, BET and SEM. The undoped catalyst was found to be more active and selective (77.6&percnt; selectivity at about 60 &percnt; conversion at 703 K).     

Kalman filter quantitative resolution of shifted ESCA spectra after optimal alignment by simulated annealing

Summary The quantitative separation of overlapped responses accomplished by the Kalman filter algorithm is deteriorated by the errors in the model due to shifts of the component peaks. This is particularly true for spectral resolution in Electron Spectroscopy for Chemical Analysis (ESCA). A computational approach for the quantitative resolution of overlapping ESCA spectra when there is loss of collinearity between the pure component peaks and the mixture peak, has been developed. The procedure makes itera tive use of the Kalman filter for resolving the mixture spectrum with the component spectra aligned according to some values of the position parameters, and of the simulated annealing algorithm to find the optimal alignment. The performance of simulated annealing in pursuing this task, has been compared with those of simplex and steepest descent, by analyzing a set of overlapped synthetic spectra and some ESCA spectra of powder mixtures of lead compounds.     

Radiochemistry at the University of Missouri-Columbia: A joint venture with chemistry,nuclear engineering,molecular biology,biochemistry, and the Missouri University Research Reactor (MURR)

Summary The United States, the Department of Energy (DOE) and its National Laboratories, including the Pacific Northwest National Laboratory (PNNL), are facing a serious attrition of nuclear scientists and engineers and their capabilities through the effects of aging staff. Within the DOE laboratories, 75&percnt; of nuclear personnel will be eligible to retire by 2010. It is expected that there will be a significant loss of senior nuclear science and technology staff at PNNL within five years. PNNL&apos;s nuclear legacy is firmly rooted in the DOE Hanford site, the World War II Manhattan Project, and subsequent programs. Historically, PNNL was a laboratory where 70&percnt; of its activities were nuclear/radiological, and now just under 50&percnt; of its current business science and technology are nuclear and radiologically oriented. Programs in the areas of nuclear legacies, global security, nonproliferation, homeland security and national defense, radiobiology and nuclear energy still involve more than 1,000 of the 3,800 current laboratory staff, and these include more than 420 staff who are certified as nuclear/radiological scientists and engineers. This paper presents the current challenges faced by PNNL that require an emerging strategy to solve the nuclear staffing issues through the maintenance and replenishment of the human nuclear capital needed to support PNNL nuclear science and technology programs.