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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

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

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

Beta-cell Assembly for the Quad Gas Sampling Detector

Description: The beta-cells used in the beta-gamma detector have taken time to develop and to standardize the assembly of them. In making the assembly routine it is important to have step by step assembly instructions as well as a list of potential problems and their solutions. This document attempts to accomplish these goals.
Date: May 5, 2008
Creator: Cooper, Matthew W.; Bowyer, Ted W.; McIntyre, Justin I.; Hayes, James C.; Heimbigner, Tom R.; Ripplinger, Michael D. et al.
Partner: UNT Libraries Government Documents Department

Computational Analysis of Coriant and PNNL Radioxenon Data Viewers

Description: The analysis by Coriant of the beta-gamma coincidence data coming from the ARSA systems show a systematic basis towards lower concentrations for all isotopes and a systematic increase in the minimum detectable concentrations. These variations can be directly traced to the method of analysis that is used by the Coriant software compared to the methods that have been developed by the International Noble Gas Experiment collaboration. This report details the differences and suggests solutions where appropriate. The report writers recommend that the algorithm changes be made to the Coriant software to bring up to the international standards.
Date: October 5, 2005
Creator: McIntyre, Justin I. & Carman, April J.
Partner: UNT Libraries Government Documents Department

Nanotechnology-Based Systems for Nuclear Radiation and Chemicl Detection

Description: This main objectives of this effort are the development and prototyping of a small. sensitive, and low-cost multi-channel nanoparticle scintillation microdevice with integrated waveguides for alpha, beta, gamma, and neutron detection. This research effort has integrated experiments and simulation to determine the combination of process-specific materials for the achievement optimum detection conditions.
Date: October 11, 2006
Creator: Varahramyan, Kody; Derosa, Pedro & Wilson, Chester
Partner: UNT Libraries Government Documents Department

SMALL-ORDER SHAPE FACTORS IN In$sup 114$, P$sup 32$, AND Y$sup 9$$sup 0$

Description: The beta spectra of In/sup 114/, P/sup 32/, and Y/sup 90/ were stud ied closely in an intermediate-image beta-ray spectrometer and compared to theoretical predictions in terms of a linear shape factor of the form (1 + aW). The values obtained for a were s for P/sup 32/, and (-0.0047 plus or minus 0.0008)/mc/sup 2/ for Y/sup 90/, all for electron kinetic energies from about 200 kev up to near the maximum beta energies. Tests were made to give indications for spectrometer fidelity. Because of the linearity of the shape-factor plots and the similarity in energy range, the comparative results from In/sup 114/, P/ sup 32/, and Y/sup 90/ are tak en as a definite indication that for at least two of these activities the shape factors have nonzero slopes, irrespective of questions of instrumental fidelity. (auth)
Date: April 1, 1961
Creator: Nichols, R.T.; McAdams, R.E. & Jensen, E.N.
Partner: UNT Libraries Government Documents Department

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. Based on ...
Date: April 15, 1998
Creator: Berthold, J. W. & Jeffers, L. A.
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