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Development of a CMOS SOI Pixel Detector

Description: We have developed a monolithic radiation pixel detector using silicon on insulator (SOI) with a commercial 0.15 {micro}m fully-depleted-SOI technology and a Czochralski high resistivity silicon substrate in place of a handle wafer. The SOI TEG (Test Element Group) chips with a size of 2.5 x 2.5 mm{sup 2} consisting of 20 x 20 {micro}m{sup 2} pixels have been designed and manufactured. Performance tests with a laser light illumination and a {beta} ray radioactive source indicate successful operation of the detector. We also briefly discuss the back gate effect as well as the simulation study.
Date: August 19, 2008
Creator: Arai, Y.; Hazumi, M.; Ikegami, Y.; Kohriki, T.; Tajima, O.; Terada, S. et al.
Partner: UNT Libraries Government Documents Department

State-of-the-Art Beta Detection and Dosimetry

Description: The research funded by this NEER grant establishes the framework for a detailed understanding of the challenges in beta dosimetry, especially in the presence of a mixed radiation field. The work also stimulated the thinking of the research group which will lead to new concepts in digital signal processing to allow collection of detection signals and real-time analysis such that simultaneous beta and gamma spectroscopy can take place. The work described herein (with detail in the many publications that came out of this research) was conducted in a manner that provided dissertation and thesis topics for three students, one of whom was completely funded by this grant. The overall benefit of the work came in the form of a dramatic shift in signal processing that is normally conducted in analog pulse shape analysis. Analog signal processing was shown not to be feasible for this type of work; digital signal processing was a must. This, in turn, led the research team to a new understanding of pulse analysis, one in which expands the state-of-the-art in simultaneous beta and gamma spectroscopy with a single detector.
Date: August 15, 2008
Creator: Hamby, David M.
Partner: UNT Libraries Government Documents Department

Calibration of a liquid scintillation counter for alpha, beta and Cerenkov counting

Description: Calibration data are presented for 25 radionuclides that were individually measured in a Packard Tri-Carb 2250CA liquid scintillation (LS) counter by both conventional and Cerenkov detection techniques. The relationships and regression data between the quench indicating parameters and the LS counting efficiencies were determined using microliter amounts of tracer added to low {sup 40}K borosilicate glass vials containing 15 mL of Insta-Gel XF scintillation cocktail. Using {sup 40}K, the detection efficiencies were linear over a three order of magnitude range (10 - 10,000 mBq) in beta activity for both LS and Cerenkov counting. The Cerenkov counting efficiency (CCE) increased linearly (42% per MeV) from 0.30 to 2.0 MeV, whereas the LS efficiency was >90% for betas with energy in excess of 0.30 MeV. The CCE was 20 - 50% less than the LS counting efficiency for beta particles with maximum energies in excess of 1 MeV. Based on replicate background measurements, the lower limit of detection (LLD) for a 1-h count at the 95% confidence level, using water as a solvent, was 0.024 counts sec-{sup -1} and 0.028 counts sec-1 for plastic and glass vials, respectively. The LLD for a 1-h-count ranged from 46 to 56 mBq (2.8 - 3.4 dpm) for both Cerenkov and conventional LS counting. This assumes: (1) a 100% counting efficiency, (2) a 50% yield of the nuclide of interest, (3) a 1-h measurement time using low background plastic vials, and (4) a 0-50 keV region of interest. The LLD is reduced an order of magnitude when the yield recovery exceeds 90% and a lower background region is used (i.e., 100 - 500 keV alpha region of interest). Examples and applications of both Cerenkov and LS counting techniques are given in the text and appendices.
Date: July 1, 1996
Creator: Scarpitta, S.C. & Fisenne, I.M.
Partner: UNT Libraries Government Documents Department

Beta contamination monitor energy response

Description: Beta contamination is monitored at Los Alamos National Laboratory (LANL) with portable handheld probes and their associated counters, smear counters, air-breathing continuous air monitors (CAM), personnel contamination monitors (PCM), and hand and foot monitors (HFM). The response of these monitors was measured using a set of anodized-aluminum beta sources for the five isotopes: Carbon-14, Technetium-99, Cesium-137, Chlorine-36 and Strontium/Yttrium-90. The surface emission rates of the sources are traceable to the National Institute of Standards and Technology (NIST) with a precision of one relative standard deviation equal to 1.7%. All measurements were made in reproducible geometry, mostly using aluminum source holders. All counts, significantly above background, were collected to a precision of 1% or better. The study of the hand-held probes included measurements of six air gaps from 0.76 to 26.2 mm. The energy response of the detectors is well-parameterized as a function of the average beta energy of the isotopes (C14=50 keV, Tc99=85, Cs137=188, C136=246, and Sr/Y90=934). The authors conclude that Chlorine-36 is a suitable beta emitter for routine calibration. They recommend that a pancake Geiger-Mueller (GM) or gas-proportional counter be used for primarily beta contamination surveys with an air gap not to exceed 6 mm. Energy response varies about 30% from Tc99 to Sr/Y90 for the pancake GM detector. Dual alpha/beta probes have poor to negligible efficiency for low-energy betas. The rugged anodized sources represent partially imbedded contamination found in the field and they are provided with precise, NIST-traceable, emission rates for reliable calibration.
Date: December 31, 1998
Creator: Bjork, C.W. & Olsher, R.H.
Partner: UNT Libraries Government Documents Department

Skin dose measurement with MICROSPEC-2{trademark}

Description: For many years, the Eberline HP-260{trademark} beta detectors were used for skin dose measurements at Los Alamos National Laboratory. This detector does not measure the beta spectrum and the skin dose can only be determined if the contaminating radioactive isotope is known. A new product MICROSPEC-2{trademark}, has been developed which consists of a small portable computer with a multichannel analyzer and a beta probe consisting of a phoswich detector. The system measures the beta spectrum and automatically folds in the beta fluence-to-dose conversion function to yield the skin dose.
Date: October 1, 1997
Creator: Hsu, H.H.; Chen, J.; Ing, H.; Clifford, E.T.H. & McLean, T.
Partner: UNT Libraries Government Documents Department

Beta and Gamma Correction Factors for the Eberline R0-20 Ionization Chamber Survey Instrument

Description: This technical document provides details of derived correction factors for the Eberline R0-20 survey meter, which uses an ionization chamber to measure ambient exposure rates. A thin end window allows the instrument to measure exposure rates from non-penetrating radiation (i.e., beta radiation). Correction factors are provided for contact measurements with beta and gamma disk sources, gamma beams and, finally, general area beta fields. Beta correction factors are based on the instrument's response to 204Tl, selected as the most conservative isotope for beta correction factors, as indicated in previous studies of similar instruments using 204Tl, 147Pm, and 90Sr(Y) isotopes (LANL 1982). Gamma correction factors are based on 137Cs, considered the predominant source of gamma radiation on the Hanford Site.
Date: August 10, 2001
Creator: Johnson, Michelle L; Rathbone, Bruce A & Bratvold, Tom
Partner: UNT Libraries Government Documents Department

Radionuclide Sensors for Subsurface Water Monitoring

Description: Contamination of the subsurface by radionuclides is a persistent and vexing problem for the Department of Energy. These radionuclides must be measured in field studies and monitoed in the long term when they cannot be removed. However, no radionuclide sensors existed for groundwater monitoring prior to this team's research under the EMSP program Detection of a and b decays from radionuclides in water is difficult due to their short ranges in condensed media.
Date: June 30, 2006
Creator: DeVol, Timothy
Partner: UNT Libraries Government Documents Department

Development of a high sensitivity monitor for radionuclides characterization. Final report, August 1995--April 1996

Description: This report describes the development of a high sensitivity monitor for radiation, and the feasibility of applying a new radiation imaging concept developed for medical research to soil contamination. The concept utilizes sensors with storage photostimulable phosphor technology as radiation detectors. They are applicable to all types of radiation including tritium.
Date: June 1, 1996
Partner: UNT Libraries Government Documents Department

Results of the radiological survey at the former Associate Aircraft Tool and Manufacturing Company site, Fairfield, Ohio (FOH001)

Description: At the request of the US Department of Energy (DOE), a team from oak Ridge National Laboratory conducted a radiological survey of the former Associate Aircraft Tool and Manufacturing Company facility, Fairfield, Ohio. The survey was performed in July and September 1992. The purpose of the survey was to determine if the facility had become contaminated with residuals containing radioactive materials during the work performed under government contract from February to September, 1956. The survey included gamma scanning over a circumscribed area around and outside of the building, and gamma scanning over most accessible indoor floor surfaces as well as the collection of soil and other samples for radionuclide analyses. Roof trusses were beta-gamma scanned in locations where floor contamination was found. Results of the survey demonstrated radionuclide concentrations in indoor and outdoor samples, and radiation measurements over floor and overhead surfaces, in excess of the DOE Formerly Utilized Sites Remedial Action Program guidelines. Elevated uranium concentrations outdoors were limited to several small, isolated spots. Radiation measurements exceeded guidelines indoors over numerous spots and areas inside the building, mainly in the areas that had been used in the early government work.
Date: March 1, 1993
Creator: Murray, M.E.; Carrier, R.F. & Mathis, R.A.
Partner: UNT Libraries Government Documents Department

Technical Basis Document (TBD) and user guides

Description: A Technical Basis Document (TBD) should provide the background information for establishment of an instrument`s operational requirements. Due to the amount and location of DOE facilities, no one set of requirements is possible. Operational requirements will vary based on the local environments and missions at each facility. Environmental conditions that can affect an instrument`s operations are ambient temperature, humidity, and radio frequency, and to a lesser extent, magnetic fields, and interfering ionizing radiations. Consideration should also be made regarding how an instrument is to be used. If an instrument will be transported around the facility, vibration and shock can cause problems if they are not addressed in the TBD. This document provides guidance for the development of a TBD. This document applies to radiation instruments used for personnel and equipment contamination monitoring, dose rate monitoring, and air monitoring.
Date: September 1998
Creator: Chiaro, P. J., Jr.
Partner: UNT Libraries Government Documents Department

Ultrahigh sensitivity heavy noble gas detectors for long-term monitoring and for monitoring air. Technical status report

Description: The primary objective of this research project is to develop heavy noble gas (krypton, xenon, and radon) detectors for (1) long-term monitoring of transuranic waste, spent fuel, and other uranium and thorium bearing wastes and (2) alpha particle air monitors that discriminate between radon emissions and other alpha emitters. A University of Cincinnati/Argonne National Laboratory (UC/ANL) Team was assembled to complete this detector development project. DOE needs that are addressed by this project include improved long-term monitoring capability and improved air monitoring capability during remedial activities. Successful development and implementation of the proposed detection systems could significantly improve current capabilities with relatively simple and inexpensive equipment.
Date: January 31, 1999
Creator: Valentine, J. D.
Partner: UNT Libraries Government Documents Department

Real-time, automated characterization of surfaces for alpha and beta radiation

Description: A new data collection system, called ABACUS{trademark}, has been developed that automates and expedites the collection, conversion, and reporting of radiological survey data of surfaces. Field testing of the system by Oak Ridge National Laboratory/Environmental Technology Section is currently underway. Preliminary results are presented. The system detects, discriminates, and separately displays the results for alpha and beta contamination scans on floors and walls with a single pass. Fixed-position static counting is also possible for quantitative measuring. The system is currently configured with five 100 cm{sup 2} dual-phosphor plastic scintillation detectors mounted in a lightweight aluminum fixture that holds the detectors in a fixed array. ABACUS{trademark} can be configured with other detectors if desired. Ratemeter/scalars traditionally coupled to individual detectors have been replaced by a single unit that houses the power supply and discriminator circuit boards to support up to five detectors. The system is designed to be used by a single operator. Each detector`s position and data are transmitted once per second and recorded on a nearby laptop computer. The data are converted to appropriate units, color-coded, and mapped to display graphically the findings for each detector in real-time. Reports can be generated immediately following the survey. Survey data can be exported in a variety of formats. Benefits of ABACUS{trademark} are: (1) immediate feedback to decision makers using the observational approach to characterization or remediation, (2) thorough documentation of survey results, (3) increased statistical confidence in scans by recording counts every second, (4) reduced paperwork and elimination of transcription errors, and (5) time and cost savings for collection, conversion, mapping, evaluating, and reporting data over traditional methods.
Date: December 31, 1997
Creator: Egidi, P.V.; Flynn, C.R.; Blair, M.S. & Selfridge, R.J.
Partner: UNT Libraries Government Documents Department

Dose algorithm determination for the Los Alamos National Laboratory personnel dosimetry system

Description: One of the most important aspects of a TLD dosimetry system is the dose algorithm used to convert the signals from the badge reader to an estimate of a worker`s dose. It is now more important then ever to have an accurate algorithm to estimate dose well below regulatory limits. Dosimetry systems for DOE laboratories must meet minimum performance standards based on DOELAP criteria. The purpose of this paper is to describe the development of a dose algorithm for a new TLD dosimeter that has been developed at Los Alamos National Laboratories. It is expected that DOELAP testing will start in 1995. Initial results indicate that the system will be able to exceed the minimum performance criteria by a large margin. The enhanced ability of the dosimeter to determine beta, gamma, and neutron energies makes it very useful in the various radiation fields encountered at the laboratory.
Date: December 31, 1995
Creator: Patterson, J.M.
Partner: UNT Libraries Government Documents Department

Progress report and technology status development of an EG and G Berthold LB-150 alpha/beta particulate monitor for use on the East Tennessee Technology Park Toxic Substances Control Act Incinerator

Description: The purpose of this project was to modify and evaluate a commercially available EG and G Berthold LB-150 alpha-beta radionuclide particulate monitor for the high-temperature and moisture-saturation conditions of the East Tennessee Technology Park (formerly K-25 Site) Toxic Substances Control Act (TSCA) Incinerator stack. The monitor was originally outfitted for operation at gas temperatures of 150 F on the defunct Los Alamos National Laboratory (LANL) controlled air incinerator, and the objective was to widen its operating envelope. A laboratory apparatus was constructed that simulated the effects of water-saturated air at the TSCA Incinerator stack-gas temperatures, 183 F. An instrumented set of heat exchangers was constructed to then condition the gas so that the radionuclide monitor could be operated without condensation. Data were collected under the conditions of the elevated temperatures and humidities and are reported herein, and design considerations of the apparatus are provided. The heat exchangers and humidification equipment performed as designed, the Mylar film held, and the instrument suffered no ill effects. However, for reasons as yet undetermined, the sensitivity of the radionuclide detection diminishes as the gas temperature is elevated, whether the gas is humidified or not. The manufacturer has had no experience with (a) the operation of the monitor under these conditions and (b) any commercial market that might exist for an instrument that operates under these conditions. The monitor was not installed into the radiologically contaminated environment of the TSCA Incinerator stack pending resolution of this technical issue.
Date: June 1, 1998
Creator: Shor, J. T.; Singh, S. P. N. & Gibson, L. V., Jr.
Partner: UNT Libraries Government Documents Department

Surface Contamination Monitor and Survey Information Management System

Description: Shonka Research Associates, Inc.`s (SRA) Surface Contamination Monitor and Survey Information management System (SCM/SIMS) is designed to perform alpha and beta radiation surveys of floors and surfaces and document the measured data. The SRA-SCM/SIMS technology can be applied to routine operational surveys, characterization surveys, and free release and site closure surveys. Any large nuclear site can make use of this technology. This report describes a demonstration of the SRA-SCM/SIMS technology. This demonstration is part of the chicago Pile-5 (CP-5) Large-Scale Demonstration Project (LSDP) sponsored by the US Department of Energy (DOE), Office of Science and Technology (ST), Deactivation and Decommissioning Focus Area (DDFA). The objective of the LSDP is to select and demonstrate potentially beneficial technologies at the Argonne National Laboratory-East`s (ANL) CP-5 Research Reactor Facility. The purpose of the LSDP is to demonstrate that by using innovative and improved deactivation and decommissioning (D and D) technologies from various sources, significant benefits can be achieved when compared to baseline D and D technologies.
Date: February 1, 1998
Partner: UNT Libraries Government Documents Department

Phase 1 Final Report for In-Situ Tritium Beta Detector

Description: The objectives of this three-phase project were to design, develop, and demonstrate a monitoring system capable of detecting and quantifying tritium in situ in ground and surface waters, and in water from effluent lines prior to discharge into public waterways. The tritium detection system design is based on measurement of the low energy beta radiation from the radioactive decay of tritium using a special form of scintillating optical fiber directly in contact with the water to be measured. The system consists of the immersible sensor module containing the optical fiber, and an electronics package, connected by an umbilical cable. The system can be permanently installed for routine water monitoring in wells or process or effluent lines, or can be moved from one location to another for survey use. The electronics will read out tritium activity directly in units of pico Curies per liter, with straightforward calibration. In Phase 1 of the project, we characterized the sensitivity of fluor-doped plastic optical fiber to tritium beta radiation. In addition, we characterized the performance of photomultiplier tubes needed for the system. In parallel with this work, we defined the functional requirements, target specifications, and system configuration for an in situ tritium beta detector that would use the fluor-doped fibers as primary sensors of tritium concentration in water. The major conclusions from the characterization work are: A polystyrene optical fiber with fluor dopant concentration of 2% gave best performance. This fiber had the highest dopant concentration of any fibers tested. Stability may be a problem. The fibers exposed to a 22-day soak in 120 F water experienced a 10x reduction in sensitivity. It is not known whether this was due to the build up of a deposit (a potentially reversible effect) or an irreversible process such as leaching of the scintillating dye.
Date: April 15, 1998
Creator: Berthold, J. W. & Jeffers, L. A.
Partner: UNT Libraries Government Documents Department