Radium-226, measurement

Krest, J. M., Moore, W. S., and Gardner, L. R. (2000). Marsh nutrient export supplied by groundwater discharge Evidence from radium measurements. Global Biogeochem. Cycles. 14, 167—176. 

Kroll, V. 1954. On the age-determination in deep-sea sediments by radium measurements. Deep-Sea Res. 1(4) 211-215. 

Joly observed elevated "Ra activities in deep-sea sediments that he attributed to water column scavenging and removal processes. This hypothesis was later challenged with the hrst seawater °Th measurements (parent of "Ra), and these new results conhrmed that radium was instead actively migrating across the marine sediment-water interface. This seabed source stimulated much activity to use radium as a tracer for ocean circulation. Unfortunately, the utility of Ra as a deep ocean circulation tracer never came to full fruition as biological cycling has been repeatedly shown to have a strong and unpredictable effect on the vertical distribution of this isotope. 

Around the beginning of this century, cancer and illness was associated with excessive use of X-rays. Watch dial painters got mouth cancer from radium in the paint. It soon was realized that radiation has health effects. The measures of energy deposition concepts introduced... 

Subsequently, a wide array of developments in TIMS methods for uranium-series measurement occurred during the past decade including initiation of methods for measurement of long-lived radium (Volpe et al. 1991 Cohen and O Nions 1991) and protactinium isotopes (Pickett et al. 1994 Bourdon et al. 1999), development of improved sources or ionization methods for TIMS analysis, and introduction of commercially available multi-collector TIMS instruments designed specifically for uranium and thorium isotopic measurement. 

Cochran JK, Masque P (2003) Short-lived U/Th-series radionuclides in the ocean tracers for scavenging rates, export fluxes and particle dynamics. Rev Mineral Geochem 52 461-492 Cohen AS, O Nions RK (1991) Precise determination of femtogram quantities of radium by thermal ionization mass spectrometry. Anal Chem 63 2705-2708 Cohen AS, Belshaw NS, O Nions RK (1992) High precision uranium, thorium, and radium isotope ratio measurements by high dynamic range thermal ionization mass spectrometry. Inti J Mass Spectrom Ion Processes 116 71-81... 

The activity is a measure of the quantity of radioactive material. For these radioactive materials it is customary to describe the activity as the number of disintegrations (transformations) per unit time. The unit of activity is the curie (Ci), which was originally related to the activity of one gram of radium, but is now defined as that quantity of radioactive material in which there are ... 

In U.S. EPA Office of Radiation Program s New House Evaluation Program (NEWHEP), two builders in the Denver area, two in Colorado Springs, and one in Southfield, Michigan, installed various radon-resistant features in houses during construction. A sampling of subsequent measurements of indoor radon, adjacent soil gas radon, and soil radium content is summarized in Table 31.6.36... 

Soil is a mixture of solid materials, air and, usually, water and organic matter. The radium content of soil often reflects that of the rocks from which the solid materials are derived by physical and chemical activity. The observed ranges are from 0 to 20 Bq kg for ultrabasic rocks (dunite) to 1 to 1835 Bq kg for igneous metamorphic rocks (gneiss) (Wollenberg, 1984). While these ranges are broader than those for measured for soils, the mean values for rocks, excluding alkali rocks, is consistent with the means observed for soils. 

Factors influencing the production and migration of radon in soils have been examined, and various sources of geographic data have been discussed. Two significant soil characteristics include air permeability and, less importantly, radium concentration. While there are, at present, few opportunities to compare the larger-scale data with on-site field measurements, those comparisons that have been made for both surface radium concentrations and air permeability of soils show a reasonable correspondence. Further comparisons between the aerial radiometric data and surface measurements are needed. Additional work and experience with SCS information on soils will improve the confidence in the permeability estimates, as will comparisons between the estimated permeabilities and actual air permeability measurements performed in the field. 

The subsoil is the principal source of radon in this house. Both the activity concentration of radium-226 in subsoil and of radon in soil gas are above levels for building ground that might result in significant indoor radon concentrations. The radon decay-product concentration in the dwelling before remedial measures were taken was substantially higher than the reference value of 120 mWL. 

Perkins [18] carried out radium and radiobarium measurements in seawater by sorption and direct multidimensional gamma-ray spectrometry. The procedure described includes the removal of radium and barium from water samples on sorption beds of barium sulfate impregnated alumina (0.5-1 cm thick) and direct counting of these beds on a multidimensional y-ray spectrometer. The radioisotopes can be removed at Unear flow rates of sample of up to 1 m/min. 

Measurements of 226radium are simpler than those for 228radium and are more precise. These measurements are generally made by concentrating the radium from up to a few litres via barium sulfate precipitation followed by thick source a counting or by 222radon extraction following dissolution of barium sulfate [21]. 

Key et al. [27] have described improved methods for the measurement of radon and radium in seawater and marine sediments using manganese dioxide impregnated fibres. The basic method that these workers used was that of Broecker [28]. Seawater samples were taken in 30 litre Niskin bottles. 

Marie (NLP 1903, NLC 1911 ) and Pierre (NLP 1903 ) Curie took up further study of Becquerel s discovery. In their studies, they made use of instrumental apparatus, designed by Pierre Curie and his brother, to measure the uranium emanations based on the fact that these emanations turn air into a conductor of electricity. In 1898, they tested an ore named pitchblende from which the element uranium was extracted and found that the electric current produced by the pitchblende in their measuring instrument was much stronger than that produced by pure uranium. They then undertook the herculean task of isolating demonstrable amounts of two new radioactive elements, polonium and radium, from the pitchblende. In their publications, they first introduced the term radio-activity to describe the phenomenon originally discovered by Becquerel. After P. Curie s early death, M. Curie did recognize that radioactive decay (radioactivity) is an atomic property. Further understanding of radioactivity awaited the contributions of E. Rutherford. 

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