Underground measurements

It should also be noted that, at ground level, materials destined for shielding purposes, such as copper and iron, win be exposed to the muon related fast neutron flux and wiU be gaining long-lived nuclides, such as °Co (in copper) and Mn (in iron), by activation. For that 

Whether dealing with low background detectors or normal laboratory systems, the MDA depends upon the continuum level beneath the measured gamma-ray peaks. 

Active background reduction is a means of reducing that continuum. I will discuss two aspects of this reduction in the Compton continuum within the spectrum and reduction of the cosmic ray continuum discussed above. Both involve additional detectors to detect gamma-rays that are either leaving the detector, in the case of Compton suppression, or might be about to enter the detector, in the case of background suppression. 

Compton scattered gamma-rays leaving the detector represent incomplete absorption of a gamma-ray. That means that the detection event will result in a count, not in the full-energy peak, as hoped, but on the Compton continuum. If we can find a way of reducing that, aU peaks standing on it will be measured with a lower uncertainty and a better MDA. 

The fact that a high Z material surrounds the HPGe spectroscopy detector is useful in that it will provide extra shielding for it - both passive and active. An external gamma-ray will have to pass through the guard detector to reach the HPGe. If it interacts with both detectors, the event will be rejected. As a side effect, escape peaks will 

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Khan, A., F. Bandi, C.R. Phillips and P. Duport, Underground Measurements of Aerosol and Radon and Thoron Progeny Activity Distributions, to be published in Proc. 191st American Chemical Society National Meeting, New York, April 13-18 (1986). 

Underground Measurements of Aerosol and Activity Distributions of Radon and Thoron Progeny... 

Progress has been reported in the use of multivariate analysis of infrared spectra of hydrocarbon-contaminated wet soil for real time in situ underground measurements [23]. 

In order to understand the abutment pressure distribution and its effects on the failure of extremely thick coal seam, underground measurements using pressure sensors and multi-position borehole extensometers were performed. The results are shown in Figures 2 and 3. 

The following diagram represents underground volumes of fluid produced. The relationship between the underground volumes (measured in reservoir barrels) and the volumes at surface conditions is discussed in Section 5.2. The relationships were denoted by... 

However the forms of the curves in fig. 5 are not fully symraetrieal. There are several causes for this nonlinear behaviour. For instance even small un-symmetrics in the coil construction or measurement errors caused by small differences in the position of the coil to the underground or the direction of coil movement influence the measured data and results in mistakes. 

The Institute has many-year experience of investigations and developments in the field of NDT. These are, mainly, developments which allowed creation of a series of eddy current flaw detectors for various applications. The Institute has traditionally studied the physico-mechanical properties of materials, their stressed-strained state, fracture mechanics and developed on this basis the procedures and instruments which measure the properties and predict the behaviour of materials. Quite important are also developments of technologies and equipment for control of thickness and adhesion of thin protective coatings on various bases, corrosion control of underground pipelines by indirect method, acoustic emission control of hydrogen and corrosion cracking in structural materials, etc. 

Detecting Leaks Small leaks are difficult to detect. The USEPA and American Petroleum Institute standard for nonlealdng underground tanks is 0.05 gaUh (3.15 cmVmin), above which a tank is considered to be leaking. Leak detection measurements can be influenced by many factors, making it difficult to detect small leaks. 

The basic standard for cathodic protection was laid down for the first time in DIN 30676 to which all the application areas of the different branches of protection can be referred. In this the most important point is the technique for accurately measuring the object/soil potential [58]. The usual off-potential measurement method for underground installations has been slowly implemented and enforced in Europe since the 1960s [59]. 

Electromagnetic (EM) Conductivity Measures the electrical conductivity of materials in microohms over a range of depths determined by the spacing and orientation of the transmitter and receiver coils, and the nature of the earth materials. Delineates areas of soil and groundwater contamination and the depth to bedrock or buried objects. Surveys to depths of SO to 100 ft are possible. Power lines, underground cables, transformers and other electrical sources severely distort the measurements. Low resistivities of surficial materials makes interpretation difficult. The top layers act as a shunt to the introduction of energy info lower layers. Capabilities for defining the variation of resistivity with depth are limited. In cases where the desired result is to map a contaminated plume in a sand layer beneath a surficial clayey soil in an area of cultural interference, or where chemicals have been spilled on the surface, or where clay soils are present it is probably not worth the effort to conduct the survey. 

Safety issues are not covered here. These are dealt with in Systems and Equipment book, and some fundamental issues will be taken up in the second edition of the Fundamentals book. The following aspects should be taken into account in system design fan safety AHU fire protection issues safety measures in mines, tunnels, underground car parks, etc. transportation of chemical and explosives. 

FIGURE 18.22 UST national backlog 1989 through 2006. (Taken from U.S. EPA, Underground Storage Tanks Corrective Action Measures Archives, FY 2006 End-of-Year Activity Report, U.S. EPA, Washington, 2007. Available at http //www.epa.gov/OUST/cat/camarchv.htm.)... 

U.S. EPA, Corrective Action Performance Measures Data, Office of Underground Storage Tanks, United States Environmental Protection Agency, Washington, DC, June 2005. 

Another group of surveys has focused on the direct modeling of some effective transport phenomena which are essential for predicting parameters that have an important role in underground gas sequestration process such as diffusivity and convection. Azin et al., in 2013, have conducted study regarding correct measurement of diffusivity coefficient [114]. 

Higher levels of lead in soil can be measured near roadways. This accumulation came from car exhaust in the past. Once lead falls onto soil, it usually sticks to soil particles. Small amounts of lead may enter rivers, lakes, and streams when soil particles are moved by rainwater. Lead may remain stuck to soil particles in water for many years. Movement of lead from soil particles into underground water or drinking water is unlikely unless the water is acidic or "soft." Movement of lead from soil will also depend on the type of lead salt or compound and on the physical and chemical characteristics of the soil. 

Steinhausler (1987) and Martell (1987) review the dosimetric models and related model studies. Their view is that there are still very large uncertainties in the existing data and in the extrapolation from the exposure and response data for underground miners and experimental animals to the health effects of the radon progeny levels to which the general public is exposed. B.L. Cohen (1987) describes his work to relate radon measurements with lung cancer rates for various geographical areas to test the concept of a dose threshold. 

A radiochemical method for the determination of Rn-220 in fumarolic gas is studied. Both condensed water and non-condensing gas are collected together and Pb-212 is precipitated as PbS. After dissolving the precipitate in conc.HCI, it is mixed with an emulsion scintillator solution for activity measurements. As Pb-214 is simultaneously measured, the observed ratio of Pb-212 /Pb-214 gives Rn-220/Rn-222. This method is superior to the method of directly measuring Rn-220 for the samples in which Rn-220/Rn-222 ratios are less than unity. This method and the previously proposed direct method were applied in the field, and new data obtained. An attempt was also made to understand the formation and transport of radon underground. 

The Rn-222 concentrations in the soil gas, fumarolic gas, atmosphere, and in the underground water have been measured extensively for the studies of seismology, uranium mining, environmental science and geochemistry. It has been known that its concentrations are often very high in fumarolic gases and in the underground water, the reason for which is, however, not clarified yet. 

The aerosol distributions are calculated in terms of a single mode, without attempting to resolve them into a major large mode and a minor very small (unattached) mode. The unattached mode is very much smaller in diameter (of molecular cluster dimensions) than the major mode of the aerosol and in underground mines its peak height is very small. To resolve such a mode would require more than the three diffusion batteries used for the measurements. 

Ninety water sources have been sampled. Deuterium content and global salt content were measured both in the underground sources (springs, drillings, wells) and in the surface sources (running water, precipitation), in order to include all the water types that might interact. 

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