Radioactive Source

Bottom hole assemblies and certain types of downhole equipment (e.g. logging tools, MWD tools) cost several US 100,000. Some logging tools will have radioactive sources which may need to be recovered or isolated for safety and legal reasons. However, prior to commencing fishing operations, a cost - benefit assessment will have to be made to establish that the time and equipment attributable to the fishing job is justified by the value of the fish or the cost of sidetracking the hole. 

Long Spacer Detector Short Spacer Detector Radioactive Source Bore Hole... 

If an intensifier, such as the 85 mm presented here, is now replacing the screen, a relative gain of the order of x50 is obtained which results in a conversion factor of 1 to 7.5 (1 incident X photon --> 7.5 electrons). This conversion efficiency not only resolves the quantum sink problem but also increases the light level significantly to compensate for the low gamma fluxes obtained from radioactive sources. 

Greater sensitivity is attained if an additional ionization mode is included. This can be in the form of a radioactive source, a heated filament, or a plasma or glow discharge. 

Lead-loaded plastics containing up to 90 wt % lead are used in x-ray protection as aprons and temporary shields in medical and industrial appHcations. Leaded glass is used to attenuate radiation where viewing the ongoing process is requited. Steel-jacketed containers fihed with lead or special lead containers are used to transfer, ship, and store fuel rods, radioactive sources, and nuclear waste. Lead is generahy used where space is limited. 

Background Radiation. If the radiation from a radioactive source is measured, the spectmm also includes contributions from the radiations from the surrounding environment. This includes radiations from the radioactivity in the materials in and around the detector, including the stmcture of the building or nearby earth. There is also cosmic radiation that comes from space and interacts with the earth and atmosphere to produce radiations that may enter the detector, and thus is observed. 

Radiation transmission methods, in which thickness is determined by (measured as) the shadow cast from a radioactive source, are limited to... 

A radioactive source was transferred from one container to another by remote operation in a shielded cell. A radiation detector, interlocked with the cell door, prevented anyone from opening the cell door when radiation could be detected inside it. To make sure the interlock was working, an operator tried to open the cell door, by remote control, during a transfer. He found he could open it. He then found that the closing mechanism would not work. Fortunately he had not opened the door very far. 

Following an incident at one plant, it was found that the plant took this to mean that the authorized person must check the presence of the sources on Mondays to Fridays but not on weekends. However, each working day means each day the radioactive source is working, not each day the authorized person is working ... 

As described in Chapter 1, the three largest radiological accidents of the last twenty years tire tlie explosion at Chernobyl, the partial core meltdown at Three Mile Island Unit 2, tuid the mishandling of a radioactive source in Brazil. The least publicized, but perhaps tlie most appropriate of tliese accidents, witli respect to waste management, was tlie situation in Brazil. 

The price per m of the other noble gases is considerably higher (Ne 70, Kr 350 and Xe 3500, and this tends to restrict their usage to specialist applications only. Radon has been used in the treatment of cancer and as a radioactive source in testing metal castings but, because of its short half-life (3.824 days) it has been superseded by more convenient materials. Such small quantities as are required are obtained as a decay product of Ra (1 g of which yields 0.64 cm in 30 days). 

Two systems are presently used by the MWD service companies concerning the radioactive source installation. One way is to lock the sources in holes in the drill collars. Thus, if the BHA is lost, the sources are left in the formation. 

Figure 4-285. Radioactive sources being installed in the neutron-density sub. (Courtesy Anadrill [113].)...

G. J. Mullaney, Temperature Determination in Flames by X-ray Absorption Using a Radioactive Source, Rev. Sci. Instr., 29, 87 (1958). The x-ray source used was radioactive Fe-55. 

The activity of a certain radioactive source is 5.3 X 103 Bq. Express this activity in curies. 

Determine the number of disintegrations per second for radioactive sources of each of the following activities ... 

A certain Geiger counter is known to respond to only 1 of every 1000 radiation events from a sample. Calculate the activity of each radioactive source in curies, given the following data (a) 591 clicks in 100. s (b) 2.7 X 104 clicks in 1.5 h ... 

The radioactive source need not aiways be introduced into the body. Inoperable brain tumors can be treated with y rays from an extemai source, usuaiiy a sampie of cobait-60. The patient is placed in a position where the y-ray beam passes through the tumor. The patient is moved so that the y rays irradiate the tumor from several angles. In this manner the tumor receives a much higher dose of radiation than the dose received by any surrounding tissues. 

Ernest Rutherford was the first person to observe a binuclear reaction, hi 1919, he exposed a sample of nitrogen to a particles from a naturally radioactive source. He observed the production of protons and deduced from the requirements of charge and mass balance that the other product was oxygen-17 ... 

In Mossbauer emission spectroscopy one prepares the catalyst with the radioactive source element (e.g. Co) and uses a suitable moving single-line absorber of Fe to record the spectra. In this way one can also study Co-containing catalysts, although strictly speaking the information concerns the iron in the catalyst that forms by the Co —> Fe decay process. 

The ionizing electrode method, also called the radioactive or ionizing probe, requires a radioactive source to ionize the gas gap and a high-... 

Radioactive source of alpha particles, embedded in lead to absorb most of the radiation. 

The diagram above shows the results of Rutherford s experiment in which he used a radioactive source to shoot alpha particles at a thin sheet of gold foil. Based on these results, what were Rutherford s conclusions ... 

---