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Cesium 139 half life

Cesium, Radioactive - Other Propertie

  1. utes) accompanied by gamma ray emission whose energy is 0.662 MeV
  2. Cesium-137 is a radioactive element with a half-life of thirty years. Its decay results in the formation of Ba-137 with a very short half-life. Both elements have the same atomic mass but cesium has an atomic number of 55 and barium has an atomic number of 56
  3. Caesium-137 (137 55 Cs), cesium-137 (US), or radiocaesium, is a radioactive isotope of caesium that is formed as one of the more common fission products by the nuclear fission of uranium-235 and other fissionable isotopes in nuclear reactors and nuclear weapons.Trace quantities also originate from natural fission of uranium-238.It is among the most problematic of the short-to-medium-lifetime.
  4. Long-term data show that Tes are significantly shorter than the physical half-life of (137)Cs in the SRS environment but that they can change over time. Therefore, it is desirable have a long period of record for calculating Tes and risky to extrapolate Tes beyond this period unless the processes governing (137)Cs removal are clearly understood

Cesium-137 has a half-life of 30 years. What does this mean? A half-life is the time it takes for a substance to reduce to half its initial size. Being a radioactive substance, Cesium-137 emits beta and gamma rays. Thus, this isotope is confined in a lead container to prevent it from being dispersed to the environment HALF-LIFE PROBLEMS Name Block 1. An isotope of cesium (cesium-137) has a half-life of 30 years. If 1,0 g of cesium-137 disintegrates over a period of 90 years, how many g of cesium-137 would remain? A We) r 2. Actinium-226 has a half-life of 29 hours. If 100 mg of actinium-226 disintegrates over

Half-life of Cs 137 Full Record Related Research Abstract The half life of Cs 137 was found to be 30.4 plus or minus 0.4 years by determining the amount of Ba 137 produced in various times from a known number of Cs 137 atoms. The numbers of barium and cesium atoms were determined from isotopedilution data obtained with a mass spectrometer. Authors particles. As noted above, cesium-137 decays to a short lived decay product, barium-137m. The latter isotope emits gamma radiation of moderate energy, which further decays to a stable form of barium. Cesium-137 is significant because of its prevalence, relatively long half life (30 years), and its potential effects on human health Cesium 137 (radiocesium) has a half-life of 30 years Cesium 137 - Radiocesium Contamination & Food Limit of 600 Bq/kg Cesium-137 is a gamma emitter with a half-life of 30.08 years. Cesium is a soft, gold-colored metal with a melting point of 28.5 °C Caesium 137 is a radioactive element with a relatively long half-life of 30.15 years. This particular isotope of caesium is both a beta and gamma emitter. It is produced in some abundance by fission reactions

Experiment #6: Half-Lif

Half-life: 30.17 years. Mode of decay: Beta and gamma radiation. Chemical properties: Liquid at room temperature, but readily bonds with chlorides to form a powder. What is it used for? Cs-137 is used in small amounts for calibration of radiation-detection equipment, such as Geiger-Mueller counters The beta decay of cesium-137 has a half-life of 30.0 years. How many years must pass to reduce a 25. The beta decay of cesium-137 has a half-life of 30.0 years. How many years must pass to reduce a 25 mg sample of cesium 137 to 8.7 mg. Categories Uncategorized. Leave a Reply Cancel reply An isotope of cesium cesium 137 has a half life of 30. Beta particle and gamma rays. Os 182 has a half life of 21 5 hours. A 2 5 gram sample of an isotope of strontium 90 was formed in a 1960 explosion of an atomic bomb at johnson island in the pacific test site I've read that Cesium 137, the radioactive compound with the longest half-life of all radiation released, has a half life of some 30 years. Meaning that now, some 30 years after the Chernobyl Disaster, it should theoretically be a lot safer, per my limited understanding of the half-life of chemicals. However, all of the articles I read and.

Caesium-137 - Wikipedi

Isotope data for cesium-149 in the Periodic Table

Cesium-137 | Cs | CID 5486527 - structure, chemical names, physical and chemical properties, classification, patents, literature, biological activities, safety/hazards/toxicity information, supplier lists, and more Cesium-137 is a gamma emitter with a half-life of 30.08 years. Cesium is a soft, gold-colored metal with a melting point of 28.5 °C. It has atomic number 55 and a relative atomic mass of 132.9.There are 35 known isotopes of the element cesium: Cesium-114 to Cesium-148 (Seelmann-Eggebert et al. 1981)

An isotope of cesium cesium-137 has a half-life of 30 years If 10 Of cesium-13. Actinium-226 has a half-life of 29 hours. If you begin with 465 mg of this isotope what mass remains after 729. Lf 10 g of cesium-137 What is the half-life of a radioactive isotope ifa 5000g sample decays to Use the following graph to answer Cesium-137 is radioactive and has a half life of 30. years. Calculate the activity of a 5.2 mg sample of ceslum-137. Give your answer in becquerels and in curies. Round your answer to 2 significant digits. 00 1 Ba x la

Cesium-137 has a half-life of 30 years; for example, if 1000 cesium-137 atoms are present, then 500 of these will be transformed into barium-137 over a 30-year period. Of the remaining 500 cesium-137 atoms, 250 will be similarly transformed over the succeeding 30-year period. Barium-137 has a half-life of 2.55 minutes Radioactive Half-life of Barium-137m loosely bound to the resin and can be de-adsorbed with a weakly acidic salt solution containing HCl and NaCl. Small aliquots of the short lived Ba-137m isotope can then be extracted from the resin by this eluting solution. The cesium atoms have a half-life of 3 Caesium is a close chemical analogue of potassium and can replace for it within the structure of clay minerals. The organic fifty percent life of retention in the body varies between types and typically boosts with boosting body mass both within and in between types. The efficient half-life of Cesium-137 in people is roughly 110 days Half life problems block name 1. What forms of radiation are released when cesium cs converts to barium ba. An isotope of cesium cesium 137 has a half life of 30 years if 1 0 of cesium 13. If 1 0 g of cesium 137 disintegrates over a period of 90 years how many g of cesium 137 would remain. The half life of cs 137 is 30 2 years. Actinium 226 has.

Effective half-life of caesium-137 in various

Answer: 3 question An isotope of cesium (cesium-139) has a half-life of 31.5 years. If 1500 g of cesium-139 disintegrates over a period of 189 years, how many grams of cesium-139 would remain? - the answers to estudyassistant.co Correct answer to the question an isotope of cesium (cesium-139) has a half-life of 31.5 years. If 1500 g of cesium-139 disintegrates over a period of 189 years, how many grams of cesium-139 would remain - e-answersolutions.co @article{osti_1117333, title = {Effective Half-Life of Caesium-137 in Various Environmental Media at the Savannah River Site}, author = {Paller, M. H. and Jannik, G. T. and Baker, R. A.}, abstractNote = {During the operational history of the Savannah River Site (SRS), many different radionuclides have been released from site facilities into the SRS environment An isotope of cesium (cesium-137) has a half-life of 30 years. If a 1.0 mg sample of cesium-137 disintegrates over a period of 90 years, how many mg of cesium-137 would remain. Categories Uncategorized. Leave a Reply Cancel reply. Your email address will not be published Cesium-137 is important due to its prevalence, comparatively lengthy half life (30 years), and its potential results on human well being. Cesium-137 emits beta particles because it decays to the barium isotope, Ba-137m (half life = 2.6 minutes)

Find step-by-step Precalculus solutions and your answer to the following textbook question: Use the radioactive decay model. The half-life of cesium-137 is 30 years. Suppose we have a 10-g sample. (a) Find a function $$ m ( t ) = m _ { 0 } 2 ^ { - t / h } $$ that models the mass remaining after t years. (b) Find a function $$ m ( t ) = m _ { 0 } e ^ { - r t } $$ that models the mass remaining. Due to the long half-life of caesium-137 (30 years), the environment of these regions were subjected to contamination, even to this day. A 1972 Brazilian case study on the carcinogenicity of caesium-137 examined the health effects in humans exposed to caesium-137. In 1987, civilians in Goiania, Brazil, were accidentally exposed to caesium-137 Half life of the cesium-137 = = initial mass of isotope N = mass of the parent isotope left after the time, (t) = half life of the isotope = rate constant Now put all the given values in this formula, we get Mass that remains after t years. Therefore, the parent isotope remain after one half life will be, 100 grams. 2) t = 70 years. N = 35.73. Math. Algebra. Algebra questions and answers. Question Cesium-137 has a half-life of about 30 years. Given this half-life, we can represent its decay with the exponential decay function A = Age-0.02314 If we begin with 200 mg of cesium-137, how much Cesium will remain after 50 years? Round to the nearest mg

The isotope cesium-137, which has a half-life of 30 years, is a product of n 03:24. Radioactive cesium 137 was emitted in large amounts in the Chernobyl nuclear 09:02. The half-life of cesium-137 is 30 years. Suppose we have a 100-mg sample. 01:17. Cesium-137, a beta emitter, has a half-life of 30 yr.. Experiment: Measurement of Ba-137 Decay & Half-life OBJECTIVES The isogenerator contains cesium-137, which decays to barium-137. The newly made barium nucleus is initially in a long-lived excited state, which eventually decays by emitting a gamma photon ( γ). A gamma photon is a high energy x-ray photon

Understanding the Half Life of Cesium 137

The cesium-137 nuclide has a half-life of 30 years. After 90 years, about 10 g remains. The original mass of the cesium-137 is closest to A) 80 g B) 60 g C) 100 g D) 90 g E) 70 Cesium (Cs, atomic number 55) is an alkali metal having 40 isotopes, ranging in mass from 112 to 151. Of these, the fission product cesium-137 (half-life 30.17 years) is of greatest concern. Cesium-137 is one of the nuclides most responsible for the radioactivity of used reactor fuel and high-level waste (with the other being strontium-90) Cobalt-60 (60Co) and caesium-137 (137 Cs) are the most widely used sources of gamma radiation. 60 Co produces gamma rays with energies of 1.173 and 1.332 MeV and has a half-life of 5.27 years, whereas 137 Cs produces gamma rays with an energy of 0.662 MeV and has a longer half-life of 30.1 years. For both isotopes, the gamma rays energies are. Caesium-137 (also spelled cesium) is a radioactive isotope which is formed mainly by nuclear fission.It has a half-life of 30.23 years, and decays by pure beta decay to a metastable nuclear isomer of barium-137 (Ba-137m).Barium-137m has a half-life of 2.55 minutes and is responsible for all of the gamma ray emission. The ground state of barium-137 is stable Cesium-137 has a half-life of 30 years. If a 2.0 g sample of cesium-137 decays over 120 years, how much would remain? A)0)25 g B)1)4 g C)0)5 g D)0)125

nstituents in control urines are presented and discussed. The biological half life of 137Cs in children was determined to be 53 ± 12 days by means of urinary assay and whole-body counting of the control group. This half life value and the average urine 137Cs levels at the six institutions were then used to estimate the average 137Cs body burdens at these institutions. Calculated estimates of. Cesium-137 has a half-life of 30.17 years and typically decays via beta emission into a meta-stable nuclear isomer of Barium (Ba-137m), which then decays via a 662 keV gamma emission to a stable isotope of Barium (Ba-137). Starting with a 10 gram sphere of Cesium-137: 1. Calculate the activity of the sphere. 2

  1. The half-life of cesium-137 is 30.2 years. If the initial mass of a sample of cesium-137 is 1.00 g, how much will remain after 30.2 years? Chemistry Nuclear Chemistry Nuclear Half-Life Calculations. 1 Answer Andy Wolff Nov 22, 2016 0.500 grams. Explanation: The half-life is the amount of time it takes for a given sample to lose half of the.
  2. e any of the values in the half-life formula given three of the four values. The calculator can also convert between half-life, mean lifetime, and decay constant given any one of the three values. Learn more about how the half-life formula is used, or explore hundreds of other math, finance, fitness, and health calculators
  3. A cesium-137 teletherapy unit, designed for treatment distances between 10 and 30 cm., was manufactured by Atomic Energy of Canada Limited (AECL) and installed in The University of Texas M. D. Anderson Hospital and Tumor Institute in March 1959.This machine is intended for the treatment of tumors which lie less than 5 cm. below the skin

Half-life of Cs 137 (Journal Article) OSTI

  1. . to the stable Ba-137 element
  2. The cesium-137 nuclide has a half-life of 30 years. After 90 years, about 10 g remains. The original mass of. asked Jun 26, 2017 in Chemistry by Lassione. the cesium-137 is closest to a. 80 g b. 60 g c. 100 g d. 90 g e. 70 g</p> general-chemistry; 0 Answers. 0 votes. answered Jun 26, 2017.
  3. Cesium-137 . An inevitable byproduct of nuclear fission is the production of fission products which are highly radioactive. Cesium-137 and strontium-90 are the most dangerous radioisotopes to the environment in terms of their long-term effects. Their intermediate half-lives of about 30 years suggests that they are not only highly radioactive but that they have a long enough halflife to be.
  4. Common Names: Cesium-137 Chemical Symbol: Cs-137 or 137Cs Atomic Number: 55 Mass Number: 137 (82 neutrons) Chemical Form: Cesium chloride Physical Form: A pellet of cesium ceramic housed in a welded stainless steel capsule Part 2 - Radiation Characteristics Physical half-life: 30.22 years Specific Activity (GBq/g): 3,220 Principle Emission
  5. Solution for The isotope cesium-137 has a half-life of 29.75 years. How long will it take a 100 gram sample of cesium-137 to decay to 75 grams from 100g to 3
  6. ute (192.0 cmp) in the year 2000. In what year will the decay rate be 3.000 cmp? AND ' A 1 kg block of phosphorous-32, which has a half-life of 14.3 days, is stored for 100.1 days. At the end of the period, how much phosphorous-32 remains.
  7. Physical Half Life is the time for a quantity of radioisotope to decay by half (Cs-137 = 30 years) Biological Half Life is the time for 1/2 of the amount of a radionuclide to be expelled from the body (CS-137 = 70 to 100 days) Effective Half Life takes into account both physical & biological half lives. The below table presents some of the.

Cesium is a naturally occurring element found combined with other elements in rocks, soil, and dust in low amounts. Naturally occurring cesium is not radioactive and is referred to as stable cesium.There is only one stable form of cesium naturally present in the environment,133Cs (read as cesium one-thirty-three). Nuclear explosions or the breakdown of uranium in fuel elements can produce two. The half-life of cesium-137 is 30.2 y. How long will it take for a sample of cesium-137 to decay to 1/8 of its original mass The isotope cesium-137, which has a half-life of 30 years, is a product of n 01:34. A radioactive sample contains $1.67 \times 10^{11}$ atoms of $\left._{47}^{1 01:58. The half-life for radioactive decay (a first-order process) of plutonium- Add To Playlist.

Caesium has at least 39 known isotopes, which is more than any other element except francium.The atomic masses of these isotopes range from 112 to 151. Even though this element has a large number of isotopes, it has only one naturally occurring stable isotope, 133 Cs. Most of the other isotopes have half-lives from a few days to fractions of a second. . The radiogenic isotope 137 Cs has been. Facts of Cesium-137. Some of the important facts about this radioactive substance are as follows: It is only one of the three metals that are liquid in room temperature (83 °F). It is a soft, malleable metal with silvery white color. Half-life of Cesium-137 is 30.17 years. Its molecular weight is 136.9071. Its nominal mass is 137 Da, average. modifier Le césium 137 , noté 137 Cs , est l'un des 40 isotopes du césium connus, élément qui a le plus grand nombre d' isotopes après le francium . Son nombre de masse est égal à 137, son noyau atomique ayant 55 protons et 82 neutrons , avec un spin 7/2+ dans son état fondamental , pour une masse atomique de 136,907 089 g/mol . Sa période est de 30,08 ans. Il est caractérisé par. Cesium-137 ( 137 Cs) is a radioisotope that has been used in both interstitial and intracavitary brachytherapy. Although Cs-137 decays via beta - decay, it is the daughter nuclide's subsequent gamma emissions that are responsible for most dose when used as an enclosed source in cancer treatment. Elemental Cesium has a low melting point (28.

131 Cs meets the criteria with the half life considerably shorter than the half lives of 125 I and 103 Pd sources. Thereby, 131 Cs offers higher initial dose rate and delivers total dose in a shorter period of time. Since 131 Cs is a new source therefore no standard has been established at NIST (or at any other competent / regulatory body). It. Cesium 137. Cesium 137 (137 Cs, Cs137) is a radioactive isotope of the alkali metal cesium which is formed primarily as a by-product of nuclear fission. Cesium 137 undergoes beta (β−) decay and has half-life of about 30 years. Cesium 137 produces gamma emission at 662 KeV and 32 KeV. The screen shown below refers to the isotope Cesium 137.

Cesium-137, specifically, is one of the two main medium-lived byproducts of uranium 235 and plutonium-239 fission (along with strontium-90). It can be highly dangerous because it is produced in large quantities, has a half-life of about 30.17 years, and reacts readily with water, making it easy to absorb into soft tissue The half-life of 137 Cs was measured with an ionization chamber by following the decay of 5 sources over a 30 years period between 1983 and 2013. The ratio between the ionization chamber current for the cesium sources and 226 Ra source was used for the half-life calculation

Isotope data for cesium-151 in the Periodic Table

Cesium 137 (radiocesium) has a half-life of 30 year

The half-life of cesium-137 is 30 years. Suppose we have a 100-mg sample. (a) Find the mass that remains after years. (b) How much of the sample remains after 100 year cesium-137 which has a half-life of 30 years. Its decay product, barium-137m (the m means metastable) stabilizes itself by emitting an energetic gamma ray with a half-life of about 2.6 minutes. It is this decay product that makes cesium an external hazard (that is, a hazard without being taken into the body). Cesium-13 Das Hauptproblem bei Cäsium-137, das in Form von Salzen vorliegt, ist seine hohe Wasserlöslichkeit. Die Cäsium-137-Ionen verteilen sich daher gut im Körper und insbesondere im Muskelgewebe. Die biologische Halbwertszeit (Half-Life) beträgt 110 Tage. Das heisst, nach 110 Tagen ist die Hälfte des Cäsiums wieder ausgeschieden Half-Life and Death: Radioactive Drinking Water Scare in Japan Subsides, but Questions Remain. As for isotopes like cesium 137, however, its decay half-life is around 30 years

Radioactivity : Caesium 13

32,000 Bq/l of cesium-137 (half-life of about 30 years), and 31,000 Bq/l Effects of radiation from Fukushima Dai-ichi on the U.S. marine environment Nearly 40% of the radioactivity in the spent fuel for both types of reactors is cesium-137 , and the pools hold about four to five times more cesium-137 than is contained in the reactor cores Cesium-137 is a very common fission product. Nuclear fission is used in nuclear power plants. The heat produced by nuclear fission can be converted into electricity. While this process is going on, cesium-137 is being produced as a by-product. That cesium-137 can be collected and used for a number of applications cesium-137. [ ′sē·zē·əm ‚wən‚thərd·ē′sev·ən] (nuclear physics) An isotope of cesium with atomic mass number of 137; emits negative beta particles and has a half-life of 30 years; offers promise as an encapsulated radiation source for therapeutic and other purposes. Also known as radiocesium 1. Health Phys. 1976 Mar;30(3):315-8. Cesium-137 body burdens and half-life in a group of adult males in Cincinnati, Ohio. Lewis JT, Grossman LW, Kereiakes JG, Saenger EL

Radioactive Fallout (fission explosion) | Physics 139 uso

Cesium-137 decay has a half-life of 30.07 years. Both the electron and gamma emissions are highly ionising radiation. RADIATION TYPE Because of it's Beta decay, Caesium is a strong emitter of gamma radiation. Caesium emits gamma rays and because of its relatively long half-life of 30 years, Cs-137 causes long lasting effect to human body. 1.173 0.415 5 (Ba-137) Max. Beta Range in air 1300 cm or 42.7 ft Max. Beta Range in water 1.5 cm Avg. gamma E = 0.662 MeV Half - life: 30.17 years or 1.1E+04 days Gamma constant: 4.24 mR/hr per 1 mCi at 30 cm Radiological data: Min. Ingestion ALI: 100 µCi equals 5 rem TEDE (Whole Body

Cesium-137 is part of the nuclear waste produced by uranium-235 fission. The half-life of cesium-137 is 30.2 years. How much time is required for the activity of a sample of cesium-137 to fall to 25.1 percent of its original value? . Cesium-137 has an atomic number of 55, so is written as #_55^137Cs#. It is also a #beta#-emitter, which means it undergoes #beta#-decay by a neutron decaying into a proton, releasing an electron.. Protons and neutrons have the same mass, so the mass number doesn't change. The atomic number increases by one, because one more proton is formed

Video: CDC Radiation Emergencies Radioisotope Brief: Cesium-137

1. Cesium-137 is part of the nuclear waste produced by uranium-235 fission. The half-life of cesium-137 is 30.2 years. How much time is required for the activity of a sample of cesium-137 to fall to 7.19 percent of its original value? _____ yrs 2.Gallium-67 is used medically in tumor-seeking agents. The half-life of gallium-67 is 78.2 hours More than twenty years after the Chernobyl accident, attention focuses mainly on one particular radioactive nucleus : caesium-137. Iodine-131, dreadful in the weeks following the disaster, has disappeared because of its 8 days radioactive half-life (or period).On the contrary, because of their periods of thirty years, the effects of cesium-137, and to a lesser degree those of one other. Cesium-137 is useful in medical and industrial radiology because of its long half-life of 30.17 years. However, as a major component of nuclear fallout and a waste product left over from the production of plutonium and other enriched nuclear fuels, it presents an environmental hazard

Since the half-life of 137 Cesium is 30.17 years, part of the radioactivity in the affected regions is still present today, and it is usually still detected in the food chain, although at lower concentration levels The half-life of cesium-137 is 30 years of an initial 100g how much cesium-137 will remain after 300 years. Expert's Answer. Solution.pdf Next Previous. Related Questions. The half-life of cesium-137 is 30 years. Suppose we have a 100-mg sample. (a) Find the mass that remains after years.. The Indian atomic energy establishment has preferred Cesium-137 as an appropriate alternative because its half-life is longer (30 years) than that of Cobalt-60 (5.27 years). Short half-life generally would mean transportation, loading and unloading, and handling the source on multiple occasions, increasing the overall security risks

Cesium 137's half-life -- the time it takes for half of a given amount of material to decay -- is 30 years. In addition to that, cesium-137's total ecological half-life -- the time for half the. The isotope cesium-137, which has a half-life of 30 years, is a product of nuclear power plants. Show that it will take 120 years for this isotope to decay to about one sixteenth its original amount? Students also viewed these Mechanics questions. The radon isotope 22286Rn,. Problem: Cesium-137 undergoes beta decay and has a half-life of 30.0 years. How many beta particles are emitted by a 14,0-g sample of cesium-137 in three minutes?6.1 x 10136.2 x 10228.4 x 10151.3 x 10-88.1 x 1015. Hey there! Radioactive decay follows first-order kinetics. The number of particles that remain after a specified time is given by Caesium-137 Poisoning. Caesium-137 has a half-life of about 30 years. However, as it is highly water soluble, in actual uses cesium-137 ions are easily accumulated in the body, where their biological half-life is 110 days. Chemical Structure. Radiocaesium (caesium-137 or cesium-137) is a byproduct resulted from the nuclear fission of uranium Caesium has at least 39 known isotopes, which is more than any other element except francium.The atomic masses of these isotopes range from 112 to 151. Even though this element has a large number of isotopes, it has only one naturally occurring stable isotope, 133 Cs. Most of the other isotopes have half-lives from a few days to fractions of a second. . The radiogenic isotope 137 Cs has been.

Isotope data for cesium-150 in the Periodic TableIsotope data for praseodymium-132 in the Periodic TableIsotope data for barium-129 in the Periodic Table

Cesium-137 Facts. Some of the important facts about this radioactive substance are as follows: It is only one of the three metals that are liquid at room temperature (83 °F). It is a soft, malleable metal with a silvery-white color. Half-life of Cesium-137 is 30.17 years. Its molecular weight is 136.9071. Its nominal mass is 137 Da, its. An isotope of Cesium -137 has a half-life of 30 years. If 1.0 g of Cesium - 137 disintegrates over. An isotope of Cesium -137 has a half-life of 30 years. If 1.0 g of Cesium - 137 disintegrates over a period of 60 years, how many grams of Cesium- 137 would remain? Categories Chemistry. Leave a Reply Cancel reply Caesium 137 replaces the traditional Cobalt 60 source as the recommended gamma source. Caesium 137 has a half life of 30 years as opposed to the 5 years for Cobalt 60 and is therefore a better long term investment. Delivery will take 4-6 weeks on these sources and a separate delivery charge will be applied. Currently this is £160 for the. cesium 137: [noun] a radioactive isotope of cesium that has the mass number 137 and a half-life of about 12 months and that is a by-product of nuclear fission Iodine-131, with its half-life of a mere eight days, was undetectable after a couple of months, Fisher explained. Cesium, of course, is a different story. The ocean and its denizens continue to bear traces of cesium-137 that date from the atmospheric weapons testing during the Cold War era of the 1960s Isotopes of Cesium (click to see decay chain): 112 Cs 113 Cs 114 Cs 115 Cs 116 Cs 117 Cs 118 Cs 119 Cs 120 Cs 121 Cs 122 Cs 123 Cs 124 Cs 125 Cs 126 Cs 127 Cs 128 Cs 129 Cs 130 Cs 131 Cs 132 Cs 133 Cs 134 Cs 135 Cs 136 Cs 137 Cs 138 Cs 139 Cs 140 Cs 141 Cs 142 Cs 143 Cs 144 Cs 145 Cs 146 Cs 147 Cs 148 Cs 149 Cs 150 Cs 151 C