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Indoor Radon and Its Decay Products: Concentrations, Causes, and Control Strategies

Description: This report is an introduction to the behavior of radon 222 and its decay products in indoor air. This includes review of basic characteristics of radon and its decay products and of features of the indoor environment itself, all of which factors affect behavior in indoor air. The experimental and theoretical evidence on behavior of radon and its decay products is examined, providing a basis for understanding the influence of geological, structural, and meteorological factors on indoor concentrations, as well as the effectiveness of control techniques. We go on to examine three important issues concerning indoor radon. We thus include (1) an appraisal of the concentration distribution in homes, (2) an examination of the utility and limitations of popular monitoring techniques and protocols, and (3) an assessment of the key elements of strategies for controlling radon levels in homes.
Date: January 1, 1990
Creator: Nero, A.V.; Gadgil, A.J.; Nazaroff, W.W. & Revzan, K.L.
Partner: UNT Libraries Government Documents Department

TRITIUM AND DECAY HELIUM EFFECTS ON THE FRACTURE TOUGHNESS PROPERTIES OF STAINLESS STEEL WELDMENTS

Description: J-Integral fracture toughness tests were conducted on tritium-exposed-and-aged Types 304L and 21-6-9 stainless steel weldments in order to measure the combined effects of tritium and its decay product, helium-3 on the fracture toughness properties. Initially, weldments have fracture toughness values about three times higher than base-metal values. Delta-ferrite phase in the weld microstructure improved toughness provided no tritium was present in the microstructure. After a tritium-exposure-and-aging treatment that resulted in {approx}1400 atomic parts per million (appm) dissolved tritium, both weldments and base metals had their fracture toughness values reduced to about the same level. The tritium effect was greater in weldments (67 % reduction vs. 37% reduction) largely because the ductile discontinuous delta-ferrite interfaces were embrittled by tritium and decay helium. Fracture toughness values decreased for both base metals and weldments with increasing decay helium content in the range tested (50-200 appm).
Date: August 31, 2007
Creator: Morgan, M; Scott West, S & Michael Tosten, M
Partner: UNT Libraries Government Documents Department

EFFECT OF TRITIUM AND DECAY HELIUM ON WELDMENT FRACTURE TOUGHNESS

Description: The fracture toughness data collected in this study are needed to assess the long-term effects of tritium and its decay product on tritium reservoirs. The results show that tritium and decay helium have negative effects on the fracture toughness properties of stainless steel and its weldments. The data and report from this study has been included in a material property database for use in tritium reservoir modeling efforts like the Technology Investment Program ''Lifecycle Engineering for Tritium Reservoirs''. A number of conclusions can be drawn from the data: (1) For unexposed Type 304L stainless steel, the fracture toughness of weldments was two to three times higher than the base metal toughness. (2) Tritium exposure lowered the fracture toughness properties of both base metals and weldments. This was characterized by lower J{sub Q} values and lower J-da curves. (3) Tritium-exposed-and-aged base metals and weldments had lower fracture toughness values than unexposed ones but still retained good toughness properties.
Date: September 26, 2006
Creator: Morgan, M; Scott West, S & Michael Tosten, M
Partner: UNT Libraries Government Documents Department

3HE RECOVERY FROM A TRITIUM-AGED LANA75 SAMPLE

Description: {sup 3}He recovery is a topic of recent interest. One potential recovery source is from metal hydride materials once used to store tritium, as the decay product, {sup 3}He, is primarily trapped in the metal lattice, usually in bubbles, with such materials. In 2001, a Tritium Exposure Program (TEP) sample known as LANA75-SP1 was retired and the material was removed from the test cell and stored. Subsequently scoping temperature programmed desorption (TPD) experiments were conducted on that material to see what it might take to drive out He and residual H isotopes (the heel). Two experiments consisted of heating the sample in the presence of an excess of tin (the so-called Sn fusion experiment), and one was a simple TPD with no additives. Prior data on the so-called '21-month bed' material in the 1980's had produced {approx}21 cc of gas per gram of a LANA30 material (LaNi4.7Al0.3), with approximately 67% of that being {sup 3}He and the rest being D{sub 2} (Fig.3). However, the material had to be heated in excess of 850 C to obtain that level. Heating to less produced approximately half that amount of gas. The data also showed that {sup 3}He was released at different temperatures than the residual hydrogen isotopes. Unfortunately this implies full {sup 3}He recovery will be a difficult process. Therefore, it seemed advisable to attempt to extract as much information from the 3 scoping experiments from 2001-2 as possible.
Date: December 1, 2010
Creator: Shanahan, K.
Partner: UNT Libraries Government Documents Department

TRITIUM RESERVOIR STRUCTURAL PERFORMANCE PREDICTION

Description: The burst test is used to assess the material performance of tritium reservoirs in the surveillance program in which reservoirs have been in service for extended periods of time. A materials system model and finite element procedure were developed under a Savannah River Site Plant-Directed Research and Development (PDRD) program to predict the structural response under a full range of loading and aged material conditions of the reservoir. The results show that the predicted burst pressure and volume ductility are in good agreement with the actual burst test results for the unexposed units. The material tensile properties used in the calculations were obtained from a curved tensile specimen harvested from a companion reservoir by Electric Discharge Machining (EDM). In the absence of exposed and aged material tensile data, literature data were used for demonstrating the methodology in terms of the helium-3 concentration in the metal and the depth of penetration in the reservoir sidewall. It can be shown that the volume ductility decreases significantly with the presence of tritium and its decay product, helium-3, in the metal, as was observed in the laboratory-controlled burst tests. The model and analytical procedure provides a predictive tool for reservoir structural integrity under aging conditions. It is recommended that benchmark tests and analysis for aged materials be performed. The methodology can be augmented to predict performance for reservoir with flaws.
Date: November 10, 2005
Creator: Lam, P.S. & Morgan, M.J
Partner: UNT Libraries Government Documents Department

A high-power target experiment at the CERN PS

Description: We test a target concept devised for the purpose of producing copious secondary pions and capturing the muon decay products. This experiment is designed to test the target system for a neutrino factory or muon collider and consists of a free flowing mercury stream embedded in a high-field solenoid. Key components are described.
Date: June 1, 2007
Creator: Kirk, H.G.; Park, H.J.; Tsang, T.; /Brookhaven; Fabich, A.; Efthymiopoulos, I. et al.
Partner: UNT Libraries Government Documents Department

Density changes in Ga-stabilized delta-Pu, and what they mean

Description: Ga-stabilized {delta}-Pu undergoes small changes in density with time. These have been associated with four different causes: an initial reversible expansion that saturates after a short time; a continuous change that can be attributed to the in-growth of helium and actinide daughter products from the radioactive decay of plutonium; possible void swelling; and phase instability. We review our present understanding of these processes and evaluate their contributions to density changes. It is shown that the initial transient expansion is intimately connected with the metastability of the {delta}-phase at ambient temperature.
Date: September 8, 2006
Creator: G.Wolfer, W; Kubota, A; S?derlind, P; Landa, A; Oudot, B; Sadigh, B et al.
Partner: UNT Libraries Government Documents Department

MEETING XVI -- BEVATRON RESEARCH CONFERENCE -- BEVATRON OPERATION

Description: The occurrence of a fault April 7 caused a short in the stator winding of one of the main generators. Repairs will require at least one month and the total time the generator will be down can be determined only after a further inspection of the damage. In a week or two, after a thorough inspection of the generator and the ignitron system, Bevatron operation will be continued on one generator. Since the targets of use in a Bevatron experiment will depend greatly on the nature of the experiment and the techniques to be employed the ideas presented here relate primarily to the area of research which involves the detection with counters of heavy mesons emitted in the backward direction in the laboratory system. These mesons and their decay products have low kinetic energy over the entire range of Bevatron energies above threshold for production. For this reason discrimination by means of momentum resolution, collimating slits, ionization density and range will be possible.
Date: April 13, 1954
Creator: Lofgren, E.J.
Partner: UNT Libraries Government Documents Department

Muon collider interaction region design

Description: Design of a muon collider interaction region (IR) presents a number of challenges arising from low {beta}* < 1 cm, correspondingly large beta-function values and beam sizes at IR magnets, as well as the necessity to protect superconducting magnets and collider detectors from muon decay products. As a consequence, the designs of the IR optics, magnets and machine-detector interface are strongly interlaced and iterative. A consistent solution for the 1.5 TeV c.o.m. muon collider IR is presented. It can provide an average luminosity of 10{sup 34} cm{sup -2}s{sup -1} with an adequate protection of magnet and detector components.
Date: May 1, 2010
Creator: Alexahin, Y.I.; Gianfelice-Wendt, E.; Kashikhin, V.V.; Mokhov, N.V.; Zlobin, A.V.; /Fermilab et al.
Partner: UNT Libraries Government Documents Department

The Potential for Dating Groundwater Using Radiogenic Noble Gases

Description: The accumulation in groundwater of products from the radioactive decay of elements naturally found in rocks offers a potential for measuring the time that the groundwater has been contact with the rock. This dating method has an advantage over using decay products from the atmosphere in that the amount of decay products increases with age rather than decreases. However, different decay products accumulate at different rates and, thus, have a different potential usefulness in age determinations. The most useful decay product is helium, produced from uranium and thorium. The use of Ar-40 produced from potassium is limited because Ar-40 is abundant in meteoric water. Neon, xenon and krypton are useful with great difficulty because they are produced in extremely small quantities. In general, the potential for error increases when a long time is required to produce a small quantity of the dating nuclide.
Date: March 23, 2001
Creator: Cornman, W.R.
Partner: UNT Libraries Government Documents Department

The Potential Use of Radioactive Decay Products for Dating Groundwater

Description: The accumulation in groundwater of products from the radioactive decay of elements naturally found in rocks offers a potential for measuring the time that the groundwater has been contact with the rock. This method of dating groundwater has an advantage over using decay products from the atmosphere in that the amount of decay product becomes greater with increasing age rather than less. However, different decay products accumulate at different rates and, thus, have a different potential usefulness in age determinations. The most useful decay product is helium, produced from uranium and thorium. Argon produced from potassium is marginally useful for very old water. Neon, xenon and krypton are probably not useful because they are produced in extremely small quantities. In general, the potential for error increases when a long time to produce a small quantity is required.
Date: March 20, 1980
Creator: Cornman, W.R.
Partner: UNT Libraries Government Documents Department

A dedicated LHC collider Beauty experiment for precision measurements of CP-violation. LHC-B letter of intent

Description: The LHC-B Collaboration proposes to build a forward collider detector dedicated to the study of CP violation and other rare phenomena in the decays of Beauty particles. The forward geometry results in an average 80 GeV momentum of reconstructed B-mesons and, with multiple, efficient and redundant triggers, yields large event samples. B-hadron decay products are efficiently identified by Ring-Imaging Cerenkov Counters, rendering a wide range of multi-particle final states accessible and providing precise measurements of all angles, {alpha}, {beta} and {gamma} of the unitarity triangle. The LHC-B microvertex detector capabilities facilitate multi-vertex event reconstruction and proper-time measurements with an expected few-percent uncertainty, permitting measurements of B{sub s}-mixing well beyond the largest conceivable values of x{sub S}. LHC-B would be fully operational at the startup of LHC and requires only a modest luminosity to reveal its full performance potential.
Date: March 28, 1996
Creator: Crosetto, Dario B.
Partner: UNT Libraries Government Documents Department

Evaluation of selected modern filter media for use in radon/thoron progeny measurements

Description: We tested a number of air sampling filters to determine their suitability for use in radon/thoron progeny measurements. The main test consisted of sampling a radon progeny atmosphere, then measuring the energy spectrum of the alpha particles emerging from the face of the filter. It was found that Millipore AA, long a favorite for this application, is still a good choice. However, this filter is prone to developing electrostatic charge, which can cause the additional collection of {sup 218}Po during filter handling. Metricel DM-800 is also a good choice, and it is less prone to charging. 12 refs., 3 figs., 2 tabs.
Date: April 1, 1996
Creator: Knutson, E.O. & Seo, Kyung-Won
Partner: UNT Libraries Government Documents Department

A conservative evaluation of the transport of TCE from the confined aquifer beneath J-Field, Aberdeen Proving Ground, Maryland, to a hypothetical receptor.

Description: Past disposal operations at the Toxic Burn Pits (TBP) area of J-Field, Aberdeen Proving Ground, Maryland, have resulted in volatile organic compound (VOC) contamination of groundwater. Although the contaminant concentration is highest in the surficial aquifer, VOCs are also present in the confined aquifer, which is approximately 30 m (100 ft) deep at the TBP area. This study focuses on the confined aquifer, a sandy valley-fill Pleistocene unit in a paleochannel cut into Cretaceous sands and clays. This report documents the locations of the region's pumping wells, which are over 6 km (4 mi) away from the TBP. The distances to the pumping wells and the complex stratigraphy limit the likelihood of any contamination reaching a receptor well. Nonetheless, a worst-case scenario was evaluated with a model designed to simulate the transport of trichloroethylene (TCE), the main chemical of concern, from the confined aquifer beneath the TBP along a hypothetical, direct flowpath to a receptor well. The model was designed to be highly conservative (i.e., based on assumptions that promote the transport of contaminants). In addition to the direct flowpath assumption, the model uses the lowest literature value for the biodegradation rate of TCE, a low degree of sorption, a continuous-strength source, and a high flow velocity. Results from this conservative evaluation indicate that the simulated contaminant plume extends into areas offshore from J-Field, but decays before reaching a receptor well. The 5-ppb contour, for example, travels approximately 5 km (3 mi) before stagnating. Recent field analyses have documented that complete biodegradation of TCE to ethene and ethane is occurring directly below the TBP; therefore, the likelihood of TCE or its daughter products reaching a pumping well appears negligible. Thus, the model results may be useful in proposing either a no action or a natural attenuation alternative for the confined ...
Date: January 4, 1999
Creator: Martino, L. E.; Patton, T. L. & Quinn, J. J.
Partner: UNT Libraries Government Documents Department

On the Suitability of Lanthanides as Actinide Analogs

Description: With the current level of actinide materials used in civilian power generation and the need for safe and efficient methods for the chemical separation of these species from their daughter products and for long-term storage requirements, a detailed understanding of actinide chemistry is of great importance. Due to the unique bonding properties of the f-elements, the lanthanides are commonly used as structural and chemical models for the actinides, but differences in the bonding between these 4f and 5f elements has become a question of immediate applicability to separations technology. This brief overview of actinide coordination chemistry in the Raymond group at UC Berkeley/LBNL examines the validity of using lanthanide analogs as structural models for the actinides, with particular attention paid to single crystal X-ray diffraction structures. Although lanthanides are commonly accepted as reasonable analogs for the actinides, these comparisons suggest the careful study of actinide materials independent of their lanthanide analogs to be of utmost importance to present and future efforts in nuclear industries.
Date: April 11, 2008
Creator: Szigethy, Geza & Raymond, Kenneth N.
Partner: UNT Libraries Government Documents Department

Measurement of the top quark mass using the template method in the lepton plus jets channel with in situ W ---> j j calibration at CDF-II

Description: We report an updated measurement of the top quark mass in the lepton plus jets channel of t{bar t} events from p{bar p} collisions at {radical}s = 1.96 TeV. This measurement uses a dataset with integrated luminosity of 680 pb{sup -1}, containing 360 t{bar t} candidates separated into four subsamples. A top quark mass is reconstructed for each event by using energy and momentum constraints on the top quark pair decay products. We also employ the reconstructed mass of hadronic W boson decays W {yields} jj to constrain in situ the largest systematic uncertainty of the top quark mass measurement: the jet energy scale. Monte Carlo templates of the reconstructed top quark and W boson mass are produced as a function of the true top quark mass and the jet energy scale. The distribution of reconstructed top quark and W boson mass in the data are compared to the Monte Carlo templates using a likelihood fit to obtain: M{sub top} = 173.4 {+-} 2.8 GeV/c{sup 2}.
Date: May 1, 2006
Creator: Adelman, Jahred A.; Arguin, J.F.; Bellettini, G.; Brubaker, E.; Budagov, J.; Chlachidze, G. et al.
Partner: UNT Libraries Government Documents Department

Numerical Investigations of the Deposition of Unattached {sup 218}Po and {sup 212}Pb from Natural Convection Enclosure Flow

Description: We report numerical predictions of the deposition to enclosure surfaces of unattached {sup 218}Po and {sup 212}Pb, short-lived decay products of {sup 222}Rn and {sup 220}Rn, respectively. The simulations are conducted for square and rectangular two-dimensional enclosures under laminar natural convection flow with Grashof numbers in the range 7 x 10{sup 7} to 8 x 10{sup 10}. The predictions are based upon a finite-difference natural-convection fluid-mechanics model that has been extended to simulate the behavior of indoor radon decay products. In the absence of airborne particles, the deposition velocity averaged over the enclosure surface was found to be in the range (2-4) x 10{sup -4} m s{sup -1} for {sup 218}Po and (1-3) x 10{sup -4} m s{sup -1} for {sup 212}Pb. In each simulation, the deposition rate varied by more than an order of magnitude around the surface of the enclosure with the largest rates occurring near corners. Attachment of decay products to airborne particles increased the deposition velocity; for example, attachment of {sup 218}Po at a rate of 50 h{sup -1} increased the predicted average deposition velocity by 30-70% over values in the absence of attachment. The simulation results have significance for assessing the health risk associated with indoor exposure to {sup 222}Rn and {sup 220}Rn decay products and for investigating the more general problem of the interaction of air pollutants with indoor surfaces.
Date: February 1, 1992
Creator: Nazaroff, W.W.; Kong, D. & Gadgil, A.J.
Partner: UNT Libraries Government Documents Department

Study of low-mass peripheral states in a small triggered bubble chamber

Description: The authors propose to study {approx} 40,000 events of the type beam particle + proton {yields} M + beam particle where M is a fairly low mass (2-5 GeV) state which is peripherally produced and slow in the lab. The decay products of M would be studied in detail as a function of M at two different beam momenta. The choice of beam particle and the two beam momenta would depend on what was technically most feasible, but at least the beam momenta should be greater than 100 GeV/c. A hydrogen bubble changer, pulsing several times per machine cycle, would be triggered on a fast forward particle near the beam momentum. The invariant mass M would be calculated for each event by momentum analysis of this particle. The experiment requires a beam with a momentum resolution {Delta}p/p of .002 or better and an emittance of .1 mm - mrad.
Date: June 1, 1970
Creator: Chapman, J.; Lys, J.; Ring, H.; Roe, B.; Sinclair, D.; VanderVelde, J. et al.
Partner: UNT Libraries Government Documents Department

A study of Central Exclusive Production

Description: Central exclusive production of a system X in a collision between two hadrons h is defined as hh {yields} h + X + h with no other activity apart from the decay products of X. This thesis presents predictions for the production cross section of a CP violating supersymmetric Higgs boson and the radion of the Randall-Sundrum model. The ExHuME Monte Carlo generator was written to simulate central exclusive processes and is described and explored. A comparison to di-jet observations made by the D0 detector at the Tevatron, Fermilab between January and June 2004 is made and the distributions found support the predictions of ExHuME.
Date: September 1, 2008
Creator: Monk, James & U., /Manchester
Partner: UNT Libraries Government Documents Department

Measurement of the Ratio BR(B+ to X e nu) / BR(B0 to X e nu)

Description: The authors report measurements of the inclusive electron momentum spectra in decays of charged and neutral B mesons, and of the ratio of semileptonic branching fractions {Beta}(B{sup +} {yields} Xe{nu}) and {Beta}(B{sup 0} {yields} Xe{nu}). These were performed on a sample of 231 million B{bar B} events recorded with the BABAR detector at the {Upsilon}(4S) resonance. Events are selected by fully reconstructing a hadronic decay of one B meson and identifying an electron among the decay products of the recoiling {bar B} meson. They obtain {Beta}(B{sup +} {yields} Xe{nu})/{Beta}(B{sup 0} {yields} Xe{nu}) = 1.084 {+-} 0.041{sub (stat)} {+-} 0.025{sub (syst)}.
Date: December 6, 2006
Creator: Aubert, B.; Bona, M.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J. P. et al.
Partner: UNT Libraries Government Documents Department

Measurements of air contaminants during the Cerro Grande fire at Los Alamos National Laboratory

Description: Ambient air sampling for radioactive air contaminants was continued throughout the Cerro Grande fire that burned part of Los Alamos National Laboratory. During the fire, samples were collected more frequently than normal because buildup of smoke particles on the filters was decreasing the air flow. Overall, actual sampling time was 96% of the total possible sampling time for the May 2000 samples. To evaluate potential human exposure to air contaminants, the samples were analyzed as soon as possible and for additional specific radionuclides. Analyses showed that the smoke from the fire included resuspended radon decay products that had been accumulating for many years on the vegetation and the forest floor that burned. Concentrations of plutonium, americium, and depleted uranium were also measurable, but at locations and concentrations comparable to non-fire periods. A continuous particulate matter sampler measured concentrations that exceeded the National Ambient Air Quality Standard for PM-10 (particles less than 10 micrometers in diameter). These high concentrations were caused by smoke from the fire when it was close to the sampler.
Date: August 1, 2010
Creator: Eberhart, Craig
Partner: UNT Libraries Government Documents Department

New Neutron Rich Nuclei Near {sup 208}Pb

Description: The level properties near the stable doubly-magic nuclei formed the experimental grounds for the theoretical description of nuclear structure. However with a departure from the beta-stability line, the classical well-established shell structure might be modified. In particular, it may even vanish for extremely exotic neutron-rich nuclei near the neutron-drip line. Presently, it is impossible to verify such predictions by a direct experimental studies of these exotic objects. However, one may try to observe and understand the evolution of the nuclear structure while departing in the experiment as far as possible from the stable nuclei. An extension of experimental nuclear structure studies towards the nuclei characterized by high neutron excess is crucial for such verifications as well as for the {tau}-process nucleosynthesis scenario. Heavy neutron-rich nuclei, south-east of doubly-magic {sup 208}Pb, were always very difficult to produce and investigate. The nuclei like {sup 218}Po and {sup 214}Pb or {sup 210}Tl marked the border line of known nuclei from the beginning of the radioactivity era for over ninety years. To illustrate the difficulties, one can refer to the experiments employing the on-line mass separator technique. A spallation of heavy targets like {sup 232}Th and {sup 238}U by high-energy protons was proven as a source of heavy neutron-rich nuclei. The isotopes near and beyond doubly-magic {sup 208}Pb were produced too. However, such studies often suffered from an isobaric contamination of much more strongly produced and efficiently released elements like francium or radon and their decay products. A new experimental technique, based on the pulsed release element selective method recently developed at the PS Booster-ISOLDE at CERN [7,8,9] greatly reduces the contamination of these very short-lived {alpha}-emitters (Z {ge} 84) for the isobaric mass chains A=215 to A=218.
Date: November 13, 1998
Creator: Aeystoe, J.; Andreyev, A.; Evensen, A.-H.; Hoff, P.; Huhta, M.; Huyse, M. et al.
Partner: UNT Libraries Government Documents Department