Tritium half-life

When the tritium (half-life 12.26 years) decays it is converted to the helium-3 isotope, which, of course, does not form covalent bonds, and so immediately departs, leaving behind the alkynyl cation. When this was done in the presence of benzene, RC CCgHs was isolated. The tritium-decay technique has also been used to generate vinylic and aryl cations. 

Water is a mixture of varying isotopic composition (Franks, 2000). In addition to the two most common isotopes, 160 and there are two stable oxygen isotopes (170, lsO), one stable hydrogen isotope (2H, deuterium), and one radioactive hydrogen isotope (3H, tritium, half-life = 12.6 years). Water also contains low concentrations of hydronium (H30+) and hydroxide ions (OH-) and their isotopic variants. In total, water consists of more than 33 chemical variants of HOH however, these variants occur in relatively minor amounts (Fennema, 1996). Table II gives the natural abundance isotopic composition of the four major water species. 

Fritz, R. and Fritz, J., 1991, Characterizing Shallow Aquifers UsingTritium and 14C Periodic Sampling Based on Tritium Half-Life Applied Geochemistry, Vol. 6, pp. 17-33. 

For an irradiation period Tr much smaller than the tritium half-life of 12.3 years, tTr < 1, and Eq. (8.54) simplifies to... 

Tritium half-life is 12.43 years (decay constant 0.0563 year )-Tritium concentration in natural objects is customary to measure in Tritium Units (TU), which describe the content of atoms per 10 atoms of protium. 1 TU corresponds with 7.088 decays per minute in a kilogram... 

Almost only fairly long-lived radioisotopes, mostly weak )5-emitters, have been used in chemical and biological investigations. Radiocarbon, C(half-life 5568 years, maximum energy 0.155 mev) and radioactive hydrogen, H(tritium) (half-life 12.26 years, maximum energy 0.018 mev) are particularly important. Radioactive phosphorus, P(14.2 days, 1.71 mev), sulphur, S(87.1 days, 0.167 mev) and iodine, H(8.04 days, 0.608 mev(j5) and several p- and y-radiations) have also often been used. 

A D—T fusion reactor is expected to have a tritium inventory of a few kilograms. Tritium is a relatively short-Hved (12.36 year half-life) and benign (beta emitter) radioactive material, and represents a radiological ha2ard many orders of magnitude less than does the fuel inventory in a fission reactor. Clearly, however, fusion reactors must be designed to preclude the accidental release of tritium or any other volatile radioactive material. There is no need to have fissile materials present in a fusion reactor, and relatively simple inspection techniques should suffice to prevent any clandestine breeding of fissile materials, eg, for potential weapons diversion. 

Tritium is radioactive and decays with a half-life of 12.26 yr. 

Decay products of the principal radionuclides used in tracer technology (see Table 1) are not themselves radioactive. Therefore, the primary decomposition events of isotopes in molecules labeled with only one radionuclide / molecule result in unlabeled impurities at a rate proportional to the half-life of the isotope. Eor and H, impurities arising from the decay process are in relatively small amounts. Eor the shorter half-life isotopes the relative amounts of these impurities caused by primary decomposition are larger, but usually not problematic because they are not radioactive and do not interfere with the application of the tracer compounds. Eor multilabeled tritiated compounds the rate of accumulation of labeled impurities owing to tritium decay can be significant. This increases with the number of radioactive atoms per molecule. 

Tritium [15086-10-9] the name given to the hydrogen isotope of mass 3, has symbol or more commonly T. Its isotopic mass is 3.0160497 (1). Moletecular tritium [10028-17-8], is analogous to the other hydrogen isotopes. The tritium nucleus is energetically unstable and decays radioactively by the emission of a low-energy P particle. The half-life is relatively short (- 12 yr), and therefore tritium occurs in nature only in equiUbrium with amounts produced by cosmic rays or man-made nuclear devices. 

The body excretes tritium with a biological half-life of 8—14 d (10.5 d average) (75), which can be reduced significantly with forced fluid intake. For humans, the estimated maximum permissible total body burden is 37 MBq (1 mCi). The median lethal dose (LD q) of tritium assimilated by the body is estimated to be 370 GBq (10 Ci). Higher doses can be tolerated with forced fluid intake to reduce the biological half-life. 

Hydrogen as it occurs in nature is predominantly composed of atoms in which the nucleus is a single proton. In addition, terrestrial hydrogen contains about 0.0156% of deuterium atoms in which the nucleus also contains a neutron, and this is the reason for its variable atomic weight (p. 17). Addition of a second neutron induces instability and tritium is radioactive, emitting low-energy particles with a half-life of 12.33 y. Some characteristic properties of these 3 atoms are given in Table 3.1, and their implications for stable isotope studies, radioactive tracer studies, and nmr spectroscopy are obvious. 

The radioactive isotope tritium, 3H, is produced in nature in much the same way as 1fC. Its half-life is 12.3 years. Estimate the 3H ratio of the tritium of water in the area to the tritium in a bottle of vine claimed to be 25 years old. 

A 100.0-g sample of water containing tritium, H, emits 2.89 X 103 beta particles per second. Tritium has a half-life of 123 years. What percentage of all the hydrogen atoms in the water sample is tritium ... 

Use tite half-life of tritium given in Problem 53 to calculate the activity in curies of 1.00 mL of 3H2 at STP. 

All radioactive decay processes follow first-order kinetics. The half-life of the radioactive isotope tritium (3H, or T) is 12.3 years. How much of a 25.0-mg sample of tritium would remain after 10.9 years ... 

The constant half-life of a nuclide is used to determine the ages of archaeological artifacts. In isotopic dating, we measure the activity of the radioactive isotopes that they contain. Isotopes used for dating objects include uranium-238, potassium-40, and tritium. However, the most important example is radiocarbon dating, which uses the decay of carbon-14, for which the half-life is 5730 a. 

Tritium—The hydrogen isotope with one proton and two neutrons in the nucleus (Symbol 3H). It is radioactive and has a physical half-life of 12.3 years. 

Estimation of total body water (virtual tritium space) in the rat, cat, rabbit, guinea-pig, and man, and of the biological half-life of tritium in man,... 

G. R., Biological half-life of tritium, Health Physics 1963, 9, 911-914. 

Cale, W. G., Jr., Fenyves, E. J., A model to estimate the biological half-life of tritium in man, Proc. Summer Comput. Simul. Conf. 1978, 629-635. 

He is present in natural gases with a concentration of MO-7 of that of 4He and 1(T6 of the helium in the atmosphere. The separation is very expensive. Hence 3He is instead obtained as by-product of tritium production in nuclear reactors. Tritium in fact produces, by beta decay (the half life is 12.26 years), 3He the separation of 3He is obtained through a diffusion process. 

The relatively short half-life of tritium (12.26 years) requires an appropriate modification of the above criteria for tritium studies made at a date later than the date of publication (1973). Also, the criteria are developed for the mid-latitudes in the northern hemisphere and should not be applied elsewhere. 

The short half-life of tritium imposes a time limit on the usefulness of tritium dating. However, because tritium decays to... 

Calculate the disintegration rate of 1 cm3 of tritium at standard temperature and pressure. What will the activity be after 2.5 years The half life of tritium is 12.26 years. Express your answers in curies and becquerels. 

Tritium The radioactive isotope of H, H, which has a half-life of approximately 12.5 y. 

Until 1931 it was assumed that hydrogen consisted of only one isotope. Urey et al. (1932) detected the presence of a second stable isotope, which was called deuterium. (In addition to these two stable isotopes there is a third naturally oc-curing but radioactive isotope, H, tritium, with a half-life of approximately 12.5 years). Rosman and Taylor (1998) gave the following average abundances of the stable hydrogen isotopes ... 

A hydrogen isotope with a nucleus consisting of one proton and two neutrons (the nucleus is referred to as the triton). Tritium, a radioisotope symbolized by iH or T, decays by negative beta emission (0.01860 MeV) with a half-life of 12.32 years. The atomic weight of tritium is 3.01605 amu. It is frequently used in metabolic and kinetic experiments. The following decay data indicate the time followed by the fraction of original amount at the specified time 0, 1.000 1 month, 0.995 2, 0.991 3,... 

It is evident from Table 1 that certain limiting factors exist. For example, experiments with bromine-82 are limited to a duration of about one week because of the short half-life. At the other end of the scale, experiments with stable carbon-13 are limited to dilutions of less than x 500. Even with radioactive isotopes the maximum specific activity available may limit dilution though not to the same extent. Thus, chlorine-36 can stand dilutions up to x 107 but tritium can improve on this to a factor of x 1012. 

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