Tritium, radiation from

In the United States, the average background dose of radiation from natural sources is about 100 mrem/year, but it can be approximately double that amount in some localities. It has been estimated that this background may contribute 4.5 to 45 cancers per million people per year. Minute amounts of radioactivity are found in all drinking waters. Some of this natural radioactivity (tritium) comes from cosmic ray bombardment. 

WILZBACH PROCEDURE. Exposure of organic compounds to tritium gas yields tntiated products of high activity without extensive radiation damage. Concentrations of tritium ranging from 1 to 90 millicuries per gram have been obtained with quite varied compounds. 

D-Glutamic acid was not found in irradiated solutions of free L-glutamic acid, which agrees with the results of Sharpless et al. 83), who found no D-alanine in irradiated L-alanine. However, Evans 14) found that a major loss of L-leucine-4,5-T, methionine-T(G), and phenylalanine-4-T amino acids stored in aqueous solution occurs as a result of racemization. In these cases, it seems likely that the inversion is a result of indirect action brought about by 0-radiation from tritium decay. 

The slope of the linear part gives the concentration-dependent radiation from the bulk of the solution. The radiation from the bulk of the tritium-labelled prothrombin at the experimental concentrations was not significant (for every microgram per milliliter it corresponds approximately to 5.10"4 fig/cm2 or at maximal experimental concentrations the radiation from the bulk above 50 cpm corresponds to about 2.5 X 10-3 ftg/cm2). The total surface counts varied at the same time between 100 cpm (in the absence of Ca++ with EDTA added) and 6,000 cpm (in the presence of lOmAf Ca++). 

Technically, any organic molecule containing a C-H bond can be labeled in one step by this procedure7 which involves exposure of an organic compound to tritium gas. The (8 radiation from the tritium... 

D. The external radiation hazard from exposure to tritium is extremely small, because the beta particles emitted cannot penetrate the dead layer of skin. However tritium is easily internalized through inhalation and absorption through the skin. The low energy beta radiation from the tritium is an internal hazard only (i.e., the isotope must get inside your body to cause damage). 

Renard and Deloche [261] examined the surface diffusion of physi-sorbed tritium on a single crystal Ni lll] surface. The gas was deposited as a patch with the crystal held at 4K and the concentration profile across the surface was determined by collection of the radiation emitted from tritium in a channeltron electron multiplier. For the diffusion experiments, the collector was positioned so as to collect radiation from a point well outside the original patch area and the sample was then heated to temperatures in the range 13—20 K. Desorption was also appreciable from, the physisorbed layer and so they derived the coverage-time relation (at fixed temperature)... 

In some cases the term submersion doses may not be appropriate because what is generally meant with this expression are the doses of direct radiation from a cloud of radioactive substances travelling in the vicinity. Here xenon-133 (important for accidents to reactors or to gaseous waste decay tanks) and tritium ( H, important for fusion machines, for example) are... 

A simple nuclear weapon derives its energy from nuclear fission. A mass of fissionable material is rapidly assembled into a critical mass, in which a chain reaction develops and releases tremendous amounts of energy. This is known as an atomic bomb. Nuclear fusion can be used to make a more powerful weapon. In such a weapon, the X-ray thermal radiation from a nuclear fission explosion is used to heat and compress a small amount of tritium, deuterium, or hthium, causing nuclear fusion, releasing even more energy. Such a weapon is called a hydrogen bomb and can be hundreds of times more powerful than an atomic bomb. 

Locante, J. Tritium in pressurized water reactors. Trans. Am. Nucl. Soc. 14, 161 — 162 (1971) Luykx, F., Fraser, G. Tritium release from nuclear power plants and nuclear reprocessing plants. Radiation Protectiori Dosimetry 16, (1—2), 31-36 (1986)... 

I can be detected alongside or in a similar way A sheet of aluminium foil, less than 0.1 mm thick, suffices to screen off the soft radiation from the radioactive sulphur and carbon, whereas the harder radiation from the radioactive iodine can pass through it. Cellophane screens off the softer radiation from tritium and permits distinction of spots containing and of comparable activity [573]. 

Cationic polymerization of isobutylene induced by radiation from tritium resulted in high-molecular-weight polymer at —78 The process involved diffusion of cations from the gas phase into the liquid phase and the rate of tritium decay was found to be independent of temperature. 

Fig. 138. Taylor s autoradiographic investigations on Vida faba. The semiconservative replication of only one chromosome is depicted. Radioactively labeled strands are red. Blackening of the photographic plate by tritium radiation = red dots (modified from Taylor et al. 1957).

Pulsed plasmas containing hydrogen isotopes can produce bursts of alpha particles and neutrons as a consequence of nuclear reactions. The neutrons are useful for radiation-effects testing and for other materials research. A dense plasma focus filled with deuterium at low pressure has produced 10 neutrons in a single pulse (76) (see Deuterium AND TRITIUM). Intense neutron fluxes also are expected from thermonuclear fusion research devices employing either magnetic or inertial confinement. 

The radioactive isotopes available for use as precursors for radioactive tracer manufacturing include barium [ C]-carbonate [1882-53-7], tritium gas, p2p] phosphoric acid or pP]-phosphoric acid [15364-02-0], p S]-sulfuric acid [13770-01 -9], and sodium [ I]-iodide [24359-64-6]. It is from these chemical forms that the corresponding radioactive tracer chemicals are synthesized. [ C]-Carbon dioxide, [ C]-benzene, and [ C]-methyl iodide require vacuum-line handling in weU-ventilated fume hoods. Tritium gas, pH]-methyl iodide, sodium borotritide, and [ I]-iodine, which are the most difficult forms of these isotopes to contain, must be handled in specialized closed systems. Sodium p S]-sulfate and sodium [ I]-iodide must be handled similarly in closed systems to avoid the Uberation of volatile p S]-sulfur oxides and [ I]-iodine. Adequate shielding must be provided when handling P P]-phosphoric acid to minimize exposure to external radiation. 

Small amounts of tritium were added to the hydrogen growth atmosphere of some crystals. Radiation detectors fabricated from these crystals measure the energy distribution of the electrons created in the tritium decays inside the crystal (Hansen et al., 1982). These studies set a lower limit of the hydrogen concentration at a value between 1014 cm 3 and 1015 cm-3. 

The end window of the tube must be thin enough to permit the weaker radiations to enter the tube (aluminium, 6-8 mg cm-2 mica, 2 mg cm-2) but even so alpha particles and very weak beta emissions are either completely or partially absorbed. The emissions from the biologically important isotopes of tritium and carbon-14 fall into this category and alternative detectors should be used for these isotopes. 

Samples of Sedan ejecta were collected around the crater lip and along several transects of the ejecta field. A 10-inch diameter hole is dug with a conventional posthole auger at each sampling station. Discrete samples are taken at depths of 6 inches, 1 foot and at 1-foot intervals below that to a depth of 5 or 6 feet. The sample is passed through a 2-mm. sieve and collected into 1-quart wide-mouthed Mason jars. Samples are shipped to the Lawrence Radiation Laboratory (Livermore, Calif.), where aliquots are taken from the jars and lyophilized on a large vacuum manifold. Individual glass traps are utilized on the manifold and extracted water from each ejecta sample is collected separately. The extracted water is assayed for tritium with a model 3375 Packard liquid... 

---