Decay Product Of Uranium Research Articles

Uranium decay products found on Mir space blanket mitt

The space blanket mitt which covered the Trek detector on Mir during four years of orbital flight has been measured for gamma radiation with HPGe and multidimensional spectrometers. Difference spectra from very-long-period spectrometer runs on the mitt and on a similar non-deployed mitt from the same manufacturer show that the mitt has acquired small but significant amounts of gamma radioactivity during orbital flight. Twelve gamma-ray peaks have been measured in the difference spectra, including peaks identified as due to 214Bi and 214Pb from the uranium–radium alpha decay series, and others possibly due to the uranium–actinium series. This implies the presence of a sparse population of uranium decay products in lower orbital space which can only have come from nuclear explosions, burned-up satellite nuclear batteries, the solar wind, or supernova fragments in the local interstellar medium.

Using Helium Isotope Composition in Underground Fluid to Estimate the Ratio of Crust/mantle Component of Continental Heat Flow

AbstractThe helium isotope 3He in underground fluid comes from the mantle by degassing process, and 4He is the decay product of uranium and thorium. Because U and Th mainly concentrate in the continental crust, so 4He flux is approximately proportional to the heat flux of crust; but 3He flux is associated with mantle heat flux. So the ratio of crust/mantle component of continental heat flow (qc/qm) is inversely related to the 3He/4He ratio of underground fluid. Based on data sets of 3He/4He ratio and qc/qm in Eurasia and Canadian Shield, we obtain the regression relation between qc/qm and 3He/4He: qc/qm = 0:815 − 0:300 ln(3He/4He), in which the unit of 3He/4He is RA (atmospheric 3He/4He ratio). Furthermore, the crust and mantle heat flow components can be taken from surface heat flow and qc/qm ratio. On the basis of this formula and heat flow data in major sedimentary basins of China, the crustal and mantle heat flow values were estimated; and the thickness of thermal lithosphere and the average crustal heat production rate inferred from these values are consistent with the results by seismology. Helium isotope ratio (3He/4He) is a useful parameter for separating crust and mantle components from continental heat flow.

A large-scale low-background liquid scintillation detector: the counting test facility at Gran Sasso

A 4.8 m 3 unsegmented liquid scintillation detector at the underground Laboratori Nazionali del Gran Sasso has shown the feasibility of multi-ton low-background detectors operating to energies as low as 250 keV. Detector construction and the handling of large volumes of liquid scintillator to minimize the background are described. The scintillator, 1.5 g PPO/L-pseudocumene, is held in a flexible nylon vessel shielded by 1000 t of purified water. The active detector volume is viewed by 100 photomultipliers, which measure time and charge for each event, from which energy, position and pulse shape are deduced. On-line purification of the scintillator by water extraction, vacuum distillation and nitrogen stripping removed radioactive impurities. Upper limits were established of < 10 −7 Bq/kg-scintillator for events with energies 250 keV < E < 800 keV, and < 10 −9 Bq/kg-scintillator due to the decay products of uranium and thorium. The isotopic abundance of 14C 12C in the scintillator was shown to be approximately 10 −18 by extending the energy window of the detector to 25–250 keV. The 14C abundance and uranium and thorium levels in the CTF are compatible with the Borexino Solar Neutrino Experiment.

SIMS Analysis of Lead Isotopes in the Primary Ore Body of the Koongarra Deposit, Australia: Behavior of Lead in the Alteration of Uranium Minerals

ABSTRACTLead, the final decay product of uranium, is found in natural uranium ore deposits. The isotope composition of lead in uranium-bearing minerals reflects their age and the migration behavior of lead. Secondary Ion Mass Spectroscopy (SIMS) can be used to analyze the isotopic composition of minerals. SIMS analysis of lead contained in the Koongarra uranium deposit, Australia, revealed that uraninite and uranyl minerals with different chemical composition in the primary ore region have homogeneous lead isotope, from the highest grade area to a uranyl silicate zone at a distance of 6.1m. Uranyl minerals, which have good crystallinity and retain stoichiometric composition, have “old” lead isotope composition identical to that of uraninite. Uranyl minerals keep exchanging lead with ground water in the primary ore region through metamictization and recrystallization by alpha-decay damage. Sulfide minerals just outside the primary ore body contain only radiogenic lead with an isotopic composition different from that of uranium minerals. Lead that migrated from the primary ore body formed sulfide minerals in a specific geological event. Since then, lead produced from uranium decay has been retained in the primary ore body, in spite of recrystallization of uranyl minerals and exchange and homogenization of lead isotopes. Uranium minerals may retain minor elements despite intense alpha-decay dose.

Dating gold artifacts applications for noble gas analyses of gold

Native gold contains gases that were incorporated when gold crystallized or that were implanted into the crystal lattice as decay products of uranium, thorium, and potassium. These elements are present in gold as trace elements. The quantity of4He produced by U and Th decay depends on the time when gold crystallized and can, thus, be used for detecting mineral fakes and, perhaps, faked ‘objets d’art’. Gold is also present in meteorites. In particular, meteorites, which represent rocks from the martian crust are of interest because magmatic activity and occurrence of liquid water in the past might have resulted in gold enrichment by hydrothermal fluids and water derived sedimentation. It is anticipated that gold deposits will eventually be detected on Mars.

Radiation-Induced Diamond Formation in Uranium-Rich Carbonaceous Materials

Nanometer-sized diamonds were identified by transmission electron microscopy in a uranium-rich, coal-like carbonaceous assemblage of Precambrian age. This observation, together with estimates of formation efficiencies, supports the hypothesis that diamond can form in carbonaceous material irradiated by the radioactive decay products of uranium. The results also suggest that the formation of carbonados cannot be sufficiently explained by a radiation mechanism alone.

Determination of alpha-emitters in Brazilian tobacco

The decay products of uranium and thorium natural series are widely distributed in all the terrestrial crust. Their concentrations are considerable in the phosphates utilized as fertilizer in the Brazilian agriculture. In this work analysis was performed on238U,234U,232Th,238Th,226Ra and210Po in 22 Brazilian tobacco samples. The results showed238U and234U are in isotopic activity equilibrium (0.5±0.2 mBq/g). The equilibrium was not reached in the case of thorium isotopes: the228/232Th ratio was about 6.4. The average values obtained were 34.3 mBq/g for228Th and 5.4 mBq/g for232Th. The226Ra values were higher than its radioactive precursor,238U. This can be explained by the high affinity of radium to tobacco plant and the uranium removal during physical and chemical processes. The high concentration of210Po (20 mBq/g) in tobacco samples may be due to radon daughter products being electrically charged and then attaching themselves to inert dusts, which then become attached to tiny hairs on tobacco leaves. The results of this work are consistent with values presented in specialized literature.

Transfer of 210Po and 210Pb through the lichen-caribou-wolf food chain of northern Canada.

Natural background activity and food chain transfer of the uranium decay products, 210Po and 210Pb, were examined in the lichen-caribou-wolf food chain at two locations in the Northwest Territories of Canada. 210Po and 210Pb activities in lichens differed with species and location. Both 210Po and 210Pb were markedly higher in caribou bone than in wolf bone. 210Po activities in liver, kidney, and muscle were similar in both species. Caribou fetuses had lower activities of 210Po but higher activities of 210Pb than maternal muscle and placenta, suggesting greater placental transport of 210Pb than 210Po. Concentration ratios (CR = Bq kg-1 in consumer/Bq kg-1 in its food source) and ff values (ff in d kg-1 = Bq kg-1 in muscle/Bq d-1 ingested) showed that wolves retain more 210Po and less 210Pb from their diet than do caribou. 210Po CRs averaged 0.38 for caribou/lichens, 0.26 for caribou/rumen contents, and 0.40 for wolves/caribou. 210Pb CRs averaged 0.36 for caribou/lichens, 0.57 for caribou/rumen contents, and 0.13 for wolves/caribou.

NORM Contamination in the Petroleum Industry

Summary Contamination of oil and gas facilities with naturally occurring radioactive materials (NORM) is widespread. Some contamination may be sufficiently severe that maintenance and other personnel may be exposed to hazardous concentrations. Contamination with radium is common in oil-production facilities, whereas contamination with radon and radon decay products is more prevalent in natural-gas production and processing facilities. Although largely unregulated until recently, U.S. states, notably Louisiana and Texas, have or are enacting legislation to control NORM contamination in the petroleum industry. Introduction NORM contamination can be expected at nearly every petroleum facility. Some of it can be sufficiently severe that maintenance and other personnel may be exposed to hazardous concentrations. In addition, the industry must comply with new regulations. Mississippi and Louisiana have enacted legislation to control NORM; Texas will have regulations early in 1993; and other states, as well as Canada, can be expected to have similar regulations shortly. Two general types of common NORM contamination will be controlled by these regulations.Radium contamination of petroleum production facilities - specifically of pipe scale and sludge and scale in surface vessels. In addition, produced water may be radioactive from radium dissolved in underground water.Radon contamination of natural-gas production facilities. This includes contamination with the long-lived decay products of radon. Facilities that remove ethane and propane from natural-gas facilities are especially susceptible to NORM contamination. Naturally occurring radionuclides are widespread in the environment. In many geologic formations, radium, radon, and other radioactive elements are associated with oil and gas. When oil and gas are produced, traces of these radioactive elements also are produced. When the formation water contains traces of radium (radium-226, a decay product of uranium, and radium-228 from thorium), scale in the production pipe can become radioactive, sometimes containing several thousand picocuries of radium per gram of scale. The radioactivity results when radium coprecipitates with barium and strontium sulfates in the scale formation.

Short-Lived Radioactivity and Magma Genesis

Short-lived decay products of uranium and thorium have half-lives and chemistries sensitive to the processes and time scales of magma genesis, including partial melting in the mantle and magmatic differentiation in the crust. Radioactive disequilibrium between (238)U, (230)Th, and (226)Ra is widespread in volcanic rocks. These disequilibria and the isotopic composition of thorium depend especially on the extent and rate of melting as well as the presence and composition of vapor during melting. The duration of mantle melting may be several hundred millennia, whereas ascent times are a few decades to thousands of years. Differentiation of most magmas commonly occurs within a few millennia, but felsic ones can be tens of millennia old upon eruption.

Radon Exposure: A Hazard to Children

BACKGROUND In December 1984, a construction engineer who lived in Boyertown, PA, triggered radiation monitors while entering the Limerick nuclear power plant near Philadelphia. He had not been contaminated by radioactive materials at the plant; therefore, his home in nearby Berks County was tested. The concentration of radon gas there was 2,700 pCi/L of air, a level much higher than had ever been measured in a residence in the United States. In January, the engineer, his wife, and their two small children were advised to leave the home immediately. The family had been exposed to radiation levels more than 50 times the annual occupational limit for uranium miners. Radon levels in an adjacent house were low but were extremely high in other nearby houses. This region of the country, known as the Reading Prong, which encompasses parts of Pennsylvania, New Jersey, and New York, has geologic deposits of low-grade uranium ore. Radon gas, a relatively common natural indoor air pollutant is a radioactive decay product of uranium. Radon and its decay products have been shown to increase the risk of lung cancer in underground miners. More recently, radon has been recognized to be widespread in homes in the United States. An estimated 13,000 lung cancer deaths per year may be attributed to residential exposure to radon gas. In this statement the hazards of exposure to radon and its decay products, known as radon progeny or radon daughters, are reviewed. NATURE AND SOURCES OF RADON Radon is a colorless, odorless, inert radioactive gas.

Environmental Radiation Survey Around a Coal-Fired Power Plant Site

Abstract For siting of a coal-fired power station in the Apulia region, ENEL (Ente Nazionale Energia Elettrica) carried out an environmental impact evaluation. Owing to the natural radioactivity in the coal and in the ash, the local authorities required an investigation of the environmental radioactivity in the area. Measurements on the radiation level, of radioactivity concentrations in soil and of radon concentration in the air were carried out at selected points on the basis of the expected atmospheric diffusion and ash disposal. At some points higher than normal radiation levels and some disequilibrium in the natural uranium decay products were observed due to hydrogeological events in the soils near the coast. A comparison is made of the radiological impact by the power plant operation and the impact due to the natural radiation environment.

Radon levels can be predicted

Scientists doing a yearlong study of radon levels in houses have identified several major factors that affect concentrations and have developed a method for predicting indoor radon levels before a house is built. Douglas Mose and George Mushrush (George Mason University, Fairfax, Va.) studied 1500 homes in northern Virginia and central Maryland near Washington, D.C.Radon is a radioactive decay product of uranium that occurs in many rock types. The gas can accumulate in buildings and pose a serious health hazard. Results from the Washington‐area study show that ∼35% of the houses had average yearly radon concentrations above 4 pico‐Curies per liter (pCi/L), the level at which the Environmental Protection Agency (EPA) suggests that a homeowner should take steps to reduce radon concentrations. At a level of 4–10 pCi/L an estimated 13–120 lung cancer deaths would be expected for every 1000 people exposed. Such a risk is comparable to having 200 chest X rays per year, according to EPA statistics.

How Serious Is the Indoor Radon Health Hazard?

YOU PAYS YOUR money and you takes your choice—or chance, as the case may be. Where radon is involved, it is hard to say just what one ought to do. Some persons apparently are convinced that exposure to this radioactive decay product of uranium is good for what ails them. (See photo.) But substantially more people seem to be concerned that radon is yet another thing to add to the list of modern woes that may do civilization in. While cure seekers apparently skeptical of legitimate medicine pay up to $4 per hour to partake of the putative benefits of radon gas in played-out uranium mines in the west, many Americans on the eastern seaboard and elsewhere, also with good health in mind, spend thousands of dollars to rid their own homes of the very same effusion. No medical authority advocates a retreat to the cave. But modern housing is

Comparison of Sodium Iodide, Cesium Iodide, and Bismuth Germanate Scintillation Detectors for Borehole Gamma-Ray Logging

NaI(Tl), CsI(Na), and Bi4Ge3O12 detectors were installed in borehole probes and used to collect gamma-ray data at the U.S. Department of Energy's calibration facility at Grand Junction, Colorado. Spectral data were collected with all three detectors to determine their ability to assay 40K, 214Bi (a decay product of uranium) and 208Tl (a decay product of thorium). Gross count data were also obtained with small NaI(Tl) and Bi4Ge3O12 detectors. Both CsI(Na) and Bi4Ge3O12M/(bismuth germanate abbreviated BGO) offer enhanced gamma-ray counting efficiency over that provided by NaI(Tl) which is the most common scintillator used in uranium exploration. Tests in calibration boreholes showed that CsI(Na) averaged 45 percent higher spectral counting efficiency than did the same size NaI(Tl) detector. BGO gave an average spectral counting efficiency 310 percent higher than did NaI(Tl). In addition, both BGO and CsI(Na) displayed smaller stripping ratios than did NaI(Tl) due to increased photopeak efficiencies. Consequently CsI(Na) and BGO provided precisions in spectral assays which were better by 20 percent and 55 percent, respectively, than the precisions obtained from NaI(Tl) detectors of the same size with the same counting times. For gross count applications BGO produced a count rate 50 percent greater than did the same size NaI(Tl) detector in an unfiltered gamma-ray probe. When a graded filter was placed around the detectors to reduce the number of low energy gamma rays detected, the count rate obtained from BGO was 90 percent greater than from Nal(Tl).

An Improved Procedure for U235 Isotopic Ratio Analysis in Impure Materials

An improved neutron activation procedure for determining the U/sup 235/ content in impure uranium samples is presented. With 95% confidence, a relative precision of plus or minus l% is obtained at the level of 0.7 wt.% U/sup 235/. An ethyl acetate extraction is used to purify the uranium chemically. Most of the uranium decay products are removed by extraction with 2- thenoyltrifluoroacetone (TTA) in xylene. The purified uranium, which is subsequently activated as U/sub 3/O/sub 8/, has a consistent gamma background level. Utilization of a 1 7/8-in. i.d.. well scintillation crystal has permitted the use of large diameter aluminum planchettes holding 2 gm aliquots of U/sub 3/O/ sub 8/. This system has minimized the problem of varying irradiation geometrics caused by differences in U/sub 3/O/sub 8/ bulk density. Data from a sample recycle program are presented to illustrate the relative precision of plus or minus 1%. Comparisons between neutron activation and mass spectrometric results agree within plus or minus l%. (auth)

Continuous determination of uranium in impure solutions by gamma spectrometry

The non-destructive determination of uranium, by measurement of the 184-KeV gamma ray activity arising from the decay of uranium-235, has been extended to the continuous monitoring of impure plant solutions. Interference in the gamma spectrometric measurement at 184 KeV by the radioactive decay products of uranium is eliminated by means of an error signal. Measurement of the decay product gamma activity at higher energies is used to produce a signal which is injected, suitably proportioned and phased, into the measurement channel. An instrument is described which is suitable for the monitoring of uranium streams containing 5–30 % w/v of natural uranium. Gross changes in the acidity and in the impurity content of the uranium stream have no appreciable effect on the indicated uranium concentration.