DOCSLIB.ORG

Einsteinium Declassified

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Einsteinium Declassified in your element Einsteinium declassified Discovered during secret testing by the United States, Joanne Redfern tells us about element 99 and why its namesake cautioned against the very technology that led to its creation. n the first of November 1952, in a top causes einsteinium to glow7. Furthermore, secret test known as Mike, the United because it decays rapidly into berkelium OStates detonated the ‘Sausage’ — the and californium, samples of einsteinium are world’s first hydrogen bomb. The explosion nearly always contaminated. annihilated the entire Pacific island of Einsteinium is mainly used to make Elugelab, but it wasn’t all devastation; at heavier elements, such as mendelevium — the same time it created two new elements first discovered by Ghiorso’s team when that their discoverers would later name bombarding 253Es with alpha particles. In einsteinium and fermium. The explosion was addition, scientists have used its radiation colossal, being more powerful than all of the to study accelerated aging and radiation high explosives used in World Wars I and II damage, and have examined its potential combined1. In an instant, an enormous for medical treatments, although not number of neutrons (around 1024–1025 cm–2, commercially7. Outside of basic research, ref. 2) blasted into the uranium atoms used einsteinium has no practical use. So although in the bomb. Some of these atoms captured its name lends it a familiarity, most of us KEYSTONE-FRANCE / GAMMA-KEYSTONE / GETTY IMAGES / GAMMA-KEYSTONE KEYSTONE-FRANCE 15 neutrons each — resulting in very will never come across even a single atom of heavy uranium isotopes — before rapidly Einstein warns of the dangers of developing the einsteinium in our lifetimes. undergoing seven beta decays. The result was hydrogen bomb (12th February 1950). Einsteinium kicked off a trend for naming a new element with an atomic number of new elements after famous scientists, and 99 and an atomic mass of 253. it is hard to imagine a scientist who would Radioactive debris — including They discovered that bombarding 238U with not appreciate this honour. But for Einstein, element 99 — mushroomed out of the nitrogen ions produced a short-lived isotope this particular element seems like an ironic explosion in a 60-mile-wide cloud. Keen of element 99, and they published their choice; he was a pacifist, vehemently opposed to understand more about the science findings in 1954 with a note to acknowledge to the development of the hydrogen bomb. He of thermonuclear explosions, the US that prior work on the element existed5. A few even recorded a statement for US television Government sent fighter jets flying through months later the Mike test was declassified, show Today with Mrs. Roosevelt (pictured) the cloud to sample the radioactive fall-out allowing Ghiorso to report his team’s earlier in which he warned that the hydrogen bomb by using special filter papers attached to discovery in 19556. He also had the honour of could annihilate life on earth. So how did he their wing tanks2. The detailed analysis choosing the name, einsteinium (Es). feel about a bomb-born element being named fell to Albert Ghiorso and colleagues at Today scientists produce einsteinium by after him? We will never know. He died just the University of California, Berkeley — bombarding plutonium with neutrons in a a few months before Ghiorso announced according to Ghiorso, the results were nuclear reactor, then allowing the resulting einsteinium to the world. ❐ entirely unexpected3. isotopes to undergo beta decay. This is a slow The team detected a unique radiation process. Indeed, it took until 1961 (nine years JOANNE REDFERN is a science and signal that they deduced must have come after its initial discovery) before scientists medical writer based in Cambridge, UK. from the hitherto unknown element 99. They managed to make enough einsteinium to e-mail: [email protected] later detected the same signal (and that of observe its form as a silvery metal4. References element 100) from radioactive coral debris As well as being scarce, einsteinium is 1. Nuclear Weapon Archive (accessed 14 August 2016); gathered from neighbouring islands. The difficult to study because it self-destructs. It http://go.nature.com/2fAKydM miniscule amount of element 99 (fewer than has nearly 20 different isotopes, all of which 2. Hoffman, D. C., Ghiorso, A. & Seaborg, G. T. The Transuranium 4 252 People: The Inside Story Ch. 6 (Imperial College Press, 2000). 200 atoms in total ) made the discovery all the are radioactive. The most stable, Es, has a 3. Ghiorso, A. Einsteinium and Fermium (Chemical and more remarkable. Frustratingly, the team were half-life of about 472 days, but it is difficult to Engineering News, American Chemical Society, 2003); not allowed to say a word as the details of the produce and is only available in tiny amounts. http://go.nature.com/2fdCSdz Mike test remained classified. 253Es is the most common isotope, but it has 4. Emsley, J. Nature’s Building Blocks: An A-Z Guide to the Elements (Oxford Univ. Press, 2011). To get around this, Ghiorso’s team set a half-life of only 20 days. It releases gamma 5. Ghiorso, A., Rossi G. B., Harvey, B. G. & Thompson, S. G. about making element 99 by other means. rays and X-rays when it decays, damaging Phys. Rev. 93, 257 (1954). its crystal lattice and hampering any X-ray 6. Ghiorso, A. et al. Phys. Rev. 99, 1048 (1955). 7. Haire, R. G. in The Chemistry of the Actinide and Transactinide crystallographic analysis. The intense Elements 3rd edn (eds Morss, L. R., Edelstein, N. M. & Fuger, J.) release of energy (1000 W per gram) also 1577–1620 (Springer, 2006). Cm Bk Cf Es Fm Md No Lr Rf Db Sg Bh Hs Mt Ds Rg Cn 113 Fl 115 Lv 1168 NATURE CHEMISTRY | VOL 8 | DECEMBER 2016 | www.nature.com/naturechemistry ©2016 Mac millan Publishers Li mited, part of Spri nger Nature. All ri ghts reserved. .
Load more

Recommended publications
  • Table 2.Iii.1. Fissionable Isotopes1
    FISSIONABLE ISOTOPES Charles P. Blair Last revised: 2012 “While several isotopes are theoretically fissionable, RANNSAD defines fissionable isotopes as either uranium-233 or 235; plutonium 238, 239, 240, 241, or 242, or Americium-241. See, Ackerman, Asal, Bale, Blair and Rethemeyer, Anatomizing Radiological and Nuclear Non-State Adversaries: Identifying the Adversary, p. 99-101, footnote #10, TABLE 2.III.1. FISSIONABLE ISOTOPES1 Isotope Availability Possible Fission Bare Critical Weapon-types mass2 Uranium-233 MEDIUM: DOE reportedly stores Gun-type or implosion-type 15 kg more than one metric ton of U- 233.3 Uranium-235 HIGH: As of 2007, 1700 metric Gun-type or implosion-type 50 kg tons of HEU existed globally, in both civilian and military stocks.4 Plutonium- HIGH: A separated global stock of Implosion 10 kg 238 plutonium, both civilian and military, of over 500 tons.5 Implosion 10 kg Plutonium- Produced in military and civilian 239 reactor fuels. Typically, reactor Plutonium- grade plutonium (RGP) consists Implosion 40 kg 240 of roughly 60 percent plutonium- Plutonium- 239, 25 percent plutonium-240, Implosion 10-13 kg nine percent plutonium-241, five 241 percent plutonium-242 and one Plutonium- percent plutonium-2386 (these Implosion 89 -100 kg 242 percentages are influenced by how long the fuel is irradiated in the reactor).7 1 This table is drawn, in part, from Charles P. Blair, “Jihadists and Nuclear Weapons,” in Gary A. Ackerman and Jeremy Tamsett, ed., Jihadists and Weapons of Mass Destruction: A Growing Threat (New York: Taylor and Francis, 2009), pp. 196-197. See also, David Albright N 2 “Bare critical mass” refers to the absence of an initiator or a reflector.
    [Show full text]
  • NOBELIUM Element Symbol: No Atomic Number: 102
    NOBELIUM Element Symbol: No Atomic Number: 102 An initiative of IYC 2011 brought to you by the RACI KERRY LAMB www.raci.org.au NOBELIUM Element symbol: No Atomic number: 102 The credit for discovering Nobelium was disputed with 3 different research teams claiming the discovery. While the first claim dates back to 1957, it was not until 1992 that the International Union of Pure and Applied Chemistry credited the discovery to a research team from Dubna in Russia for work they did in 1966. The element was named Nobelium in 1957 by the first of its claimed discoverers (the Nobel Institute in Sweden). It was named after Alfred Nobel, a Swedish chemist who invented dynamite, held more than 350 patents and bequeathed his fortune to the establishment of the Nobel Prizes. Nobelium is a synthetic element and does not occur in nature and has no known uses other than in scientific research as only tiny amounts of the element have ever been produced. Nobelium is radioactive and most likely metallic. The appearance and properties of Nobelium are unknown as insufficient amounts of the element have been produced. Nobelium is made by the bombardment of curium (Cm) with carbon nuclei. Its most stable isotope, 259No, has a half-life of 58 minutes and decays to Fermium (255Fm) through alpha decay or to Mendelevium (259Md) through electron capture. Provided by the element sponsor Freehills Patent and Trade Mark Attorneys ARTISTS DESCRIPTION I wanted to depict Alfred Nobel, the namesake of Nobelium, as a resolute young man, wearing the Laurel wreath which is the symbol of victory.
    [Show full text]
  • Copyrighted Material
    ftoc.qrk 5/24/04 1:46 PM Page iii Contents Timeline v de Sitter,Willem 72 Dukas, Helen 74 Introduction 1 E = mc2 76 Eddington, Sir Arthur 79 Absentmindedness 3 Education 82 Anti-Semitism 4 Ehrenfest, Paul 85 Arms Race 8 Einstein, Elsa Löwenthal 88 Atomic Bomb 9 Einstein, Mileva Maric 93 Awards 16 Einstein Field Equations 100 Beauty and Equations 17 Einstein-Podolsky-Rosen Besso, Michele 18 Argument 101 Black Holes 21 Einstein Ring 106 Bohr, Niels Henrik David 25 Einstein Tower 107 Books about Einstein 30 Einsteinium 108 Born, Max 33 Electrodynamics 108 Bose-Einstein Condensate 34 Ether 110 Brain 36 FBI 113 Brownian Motion 39 Freud, Sigmund 116 Career 41 Friedmann, Alexander 117 Causality 44 Germany 119 Childhood 46 God 124 Children 49 Gravitation 126 Clothes 58 Gravitational Waves 128 CommunismCOPYRIGHTED 59 Grossmann, MATERIAL Marcel 129 Correspondence 62 Hair 131 Cosmological Constant 63 Heisenberg, Werner Karl 132 Cosmology 65 Hidden Variables 137 Curie, Marie 68 Hilbert, David 138 Death 70 Hitler, Adolf 141 iii ftoc.qrk 5/24/04 1:46 PM Page iv iv Contents Inventions 142 Poincaré, Henri 220 Israel 144 Popular Works 222 Japan 146 Positivism 223 Jokes about Einstein 148 Princeton 226 Judaism 149 Quantum Mechanics 230 Kaluza-Klein Theory 151 Reference Frames 237 League of Nations 153 Relativity, General Lemaître, Georges 154 Theory of 239 Lenard, Philipp 156 Relativity, Special Lorentz, Hendrik 158 Theory of 247 Mach, Ernst 161 Religion 255 Mathematics 164 Roosevelt, Franklin D. 258 McCarthyism 166 Russell-Einstein Manifesto 260 Michelson-Morley Experiment 167 Schroedinger, Erwin 261 Millikan, Robert 171 Solvay Conferences 265 Miracle Year 174 Space-Time 267 Monroe, Marilyn 179 Spinoza, Baruch (Benedictus) 268 Mysticism 179 Stark, Johannes 270 Myths and Switzerland 272 Misconceptions 181 Thought Experiments 274 Nazism 184 Time Travel 276 Newton, Isaac 188 Twin Paradox 279 Nobel Prize in Physics 190 Uncertainty Principle 280 Olympia Academy 195 Unified Theory 282 Oppenheimer, J.
    [Show full text]
  • Periodic Table 1 Periodic Table
    Periodic table 1 Periodic table This article is about the table used in chemistry. For other uses, see Periodic table (disambiguation). The periodic table is a tabular arrangement of the chemical elements, organized on the basis of their atomic numbers (numbers of protons in the nucleus), electron configurations , and recurring chemical properties. Elements are presented in order of increasing atomic number, which is typically listed with the chemical symbol in each box. The standard form of the table consists of a grid of elements laid out in 18 columns and 7 Standard 18-column form of the periodic table. For the color legend, see section Layout, rows, with a double row of elements under the larger table. below that. The table can also be deconstructed into four rectangular blocks: the s-block to the left, the p-block to the right, the d-block in the middle, and the f-block below that. The rows of the table are called periods; the columns are called groups, with some of these having names such as halogens or noble gases. Since, by definition, a periodic table incorporates recurring trends, any such table can be used to derive relationships between the properties of the elements and predict the properties of new, yet to be discovered or synthesized, elements. As a result, a periodic table—whether in the standard form or some other variant—provides a useful framework for analyzing chemical behavior, and such tables are widely used in chemistry and other sciences. Although precursors exist, Dmitri Mendeleev is generally credited with the publication, in 1869, of the first widely recognized periodic table.
    [Show full text]
  • Genius of the Periodic Table
    GENIUS OF THE PERIODIC TABLE "Isn't it the work of a genius'. " exclaimed Academician V.I. Spitsyn, USSR, a member of the Scientific Advisory Committee when talking to an Agency audience in January. His listeners shared his enthusiasm. Academician Spitsyn was referring to the to the first formulation a hundred years ago by Professor Dmitry I. Mendeleyev of the Periodic Law of Elements. In conditions of enormous difficulty, considering the lack of data on atomic weights of elements, Mendeleyev created in less than two years work at St. Petersburg University, a system of chemical elements that is, in general, still being used. His law became a powerful instrument for further development of chemistry and physics. He was able immediately to correct the atomic weight numbers of some elements, including uranium, whose atomic weight he found to be double that given at the time. Two years later Mendeleyev went so far as to give a detailed description of physical or chemical properties of some elements which were as yet undiscovered. Time gave striking proof of his predictions and his periodic law. Mendeleyev published his conclusions in the first place by sending, early in March 186 9, a leaflet to many Russian and foreign scientists. It gave his system of elements based on their atomic weights and chemical resemblance. On the 18th March that year his paper on the subject was read at the meeting of the Russian Chemical Society, and two months later the Society's Journal published his article entitled "The correlation between properties of elements and their atomic weight".
    [Show full text]
  • First Observation of Atomic Levels for the Element Fermium (Z ˆ 100)
    PHYSICAL REVIEW LETTERS week ending VOLUME 90, NUMBER 16 25 APRIL 2003 First Observation of Atomic Levels for the Element Fermium (Z 100) M. Sewtz, H. Backe, A. Dretzke, G. Kube, W. Lauth, and P. Schwamb Institut fu¨r Kernphysik, Universita¨t Mainz, D-55099 Mainz, Germany K. Eberhardt, C. Gru¨ning, P. Tho¨rle, and N. Trautmann Institut fu¨r Kernchemie, Universita¨t Mainz, D-55099 Mainz, Germany P. Kunz, J. Lassen, and G. Passler Institut fu¨r Physik, Universita¨t Mainz, D-55099 Mainz, Germany C. Z. Dong and S. Fritzsche Fachbereich Physik, Universita¨t Kassel, D-34132 Kassel, Germany R. G. Haire Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6375 (Received 25 October 2002; revised manuscript received 6 March 2003; published 25 April 2003) The atomic level structure of the element fermium was investigated for the first time using a sample of 2:7 1010 atoms of the isotope 255Fm with a half-life of 20.1 h. The atoms were evaporated from a filament and stored in the argon buffer gas of an optical cell. Atomic levels were sought by the method of resonance ionization spectroscopy using an excimer-dye-laser combination. Two atomic levels were found at wave numbers 25 099:8 0:2 and 25 111:8 0:2 cmÿ1. Partial transition rates to the 12 23 e 5f 7s H6 ground state have been determined from their saturation characteristics. Multiconfiguration 12 5 o Dirac-Fock calculations suggest that the leading orders of these levels could be the 5f 7s7p I6 and 12 5 o 5f 7s7p G5 terms.
    [Show full text]
  • Peaceful Berkelium
    in your element Peaceful berkelium The first new element produced after the Second World War has led a rather peaceful life since entering the period table — until it became the target of those producing superheavy elements, as Andreas Trabesinger describes. f nomenclature were transitive, element 97 with the finding that in Bk(iii) compounds would be named after an Irish bishop spin–orbit coupling leads to a mixing of the Iwhose philosophical belief was that first excited state and the ground state. This material things do not exist. But between gives rise to unexpected electronic properties the immaterialist George Berkeley and the not present in analogous lanthanide element berkelium stands, of course, the structures containing terbium. Even more fine Californian city of Berkeley (pictured), recently5, a combined experimental and where the element was first produced in computational study revealed that berkelium December 1949. The city became the eponym can have stabilized +iii and +iV oxidation of element 97 “in a manner similar to that states also under mild aqueous conditions, used in naming its chemical homologue indicating a path to separating it from other terbium […] whose name was derived from lanthanides and actinides. the town of Ytterby, Sweden, where the rare The main use of berkelium, however — earth minerals were first found”1. arguably one that wouldn’t have met with A great honour for the city? The mayor Bishop Berkeley’s approval — remains a of Berkeley at the time reportedly displayed PHOTO STOCK / ALAMY AF ARCHIVE distinctly material one: as the target for “a complete lack of interest when he was the synthesis of other transuranium and called with the glad tidings”2.
    [Show full text]
  • BNL-79513-2007-CP Standard Atomic Weights Tables 2007 Abridged To
    BNL-79513-2007-CP Standard Atomic Weights Tables 2007 Abridged to Four and Five Significant Figures Norman E. Holden Energy Sciences & Technology Department National Nuclear Data Center Brookhaven National Laboratory P.O. Box 5000 Upton, NY 11973-5000 www.bnl.gov Prepared for the 44th IUPAC General Assembly, in Torino, Italy August 2007 Notice: This manuscript has been authored by employees of Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. The publisher by accepting the manuscript for publication acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. This preprint is intended for publication in a journal or proceedings. Since changes may be made before publication, it may not be cited or reproduced without the author’s permission. DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, nor any of their contractors, subcontractors, or their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or any third party’s use or the results of such use of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof or its contractors or subcontractors.
    [Show full text]
  • Remarkable Complexation and Stabilization of Berkelium(IV) by A
    Remarkable complexation and stabilization of berkelium(IV) by a synthetic siderophore: An experimental and theoretical comparison with neighboring trivalent actinide elements Gauthier J-P. Deblonde1, Manuel Sturzbecher-Hoehne1, Peter B. Rupert,2 Dahlia D. An,1 Marie-Claire Illy,1 Corie Y. Ralston,3 Jiri Brabec,4 Wibe A. de Jong*,5 Roland K. Strong*,2 and Rebecca J. Abergel* 1 1 Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA 2 Division of Basic Science, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA 3 Berkeley Center for Structural Biology, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA 4 J. Heyrovsky Institute of Physical Chemistry, 18223 Prague 8, Czech Republic 5 Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA Keywords: Berkelium; Californium; Actinides; Chelation; Separation; Luminescence; Sensitization Page 1 Abstract Despite theoretical assertions of berkelium (Bk) being the only transplutonium element that can exhibit +III and +IV oxidation states in solution, evidence of a stable oxidized Bk chelate has so far been elusive. Using a siderophore derivative, stabilization of the heaviest 4+ ion of the periodic table was achieved under mild aqueous conditions. The resulting Bk(IV) complex exhibits unprecedented sensitized luminescence through ligand-to-metal energy transfer, but also inhibits Bk interactions with the protein siderocalin, a mammalian metal transporter. Formation of this neutral Bk(IV) coordination compound contrasts sharply with the corresponding negatively charged species incorporating neighboring trivalent americium, curium and californium (Cf), which are sequestered by siderocalin, as evidenced by Xray diffraction analysis of the Cf(III)-ligand-protein ternary adduct, the first example and crystallographic characterization of a Cf macromolecular assembly.
    [Show full text]
  • Python Module Index 79
    mendeleev Documentation Release 0.9.0 Lukasz Mentel Sep 04, 2021 CONTENTS 1 Getting started 3 1.1 Overview.................................................3 1.2 Contributing...............................................3 1.3 Citing...................................................3 1.4 Related projects.............................................4 1.5 Funding..................................................4 2 Installation 5 3 Tutorials 7 3.1 Quick start................................................7 3.2 Bulk data access............................................. 14 3.3 Electronic configuration......................................... 21 3.4 Ions.................................................... 23 3.5 Visualizing custom periodic tables.................................... 25 3.6 Advanced visulization tutorial...................................... 27 3.7 Jupyter notebooks............................................ 30 4 Data 31 4.1 Elements................................................. 31 4.2 Isotopes.................................................. 35 5 Electronegativities 37 5.1 Allen................................................... 37 5.2 Allred and Rochow............................................ 38 5.3 Cottrell and Sutton............................................ 38 5.4 Ghosh................................................... 38 5.5 Gordy................................................... 39 5.6 Li and Xue................................................ 39 5.7 Martynov and Batsanov........................................
    [Show full text]
  • The Elements.Pdf
    A Periodic Table of the Elements at Los Alamos National Laboratory Los Alamos National Laboratory's Chemistry Division Presents Periodic Table of the Elements A Resource for Elementary, Middle School, and High School Students Click an element for more information: Group** Period 1 18 IA VIIIA 1A 8A 1 2 13 14 15 16 17 2 1 H IIA IIIA IVA VA VIAVIIA He 1.008 2A 3A 4A 5A 6A 7A 4.003 3 4 5 6 7 8 9 10 2 Li Be B C N O F Ne 6.941 9.012 10.81 12.01 14.01 16.00 19.00 20.18 11 12 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 3 Na Mg IIIB IVB VB VIB VIIB ------- VIII IB IIB Al Si P S Cl Ar 22.99 24.31 3B 4B 5B 6B 7B ------- 1B 2B 26.98 28.09 30.97 32.07 35.45 39.95 ------- 8 ------- 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 4 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr 39.10 40.08 44.96 47.88 50.94 52.00 54.94 55.85 58.47 58.69 63.55 65.39 69.72 72.59 74.92 78.96 79.90 83.80 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 5 Rb Sr Y Zr NbMo Tc Ru Rh PdAgCd In Sn Sb Te I Xe 85.47 87.62 88.91 91.22 92.91 95.94 (98) 101.1 102.9 106.4 107.9 112.4 114.8 118.7 121.8 127.6 126.9 131.3 55 56 57 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 6 Cs Ba La* Hf Ta W Re Os Ir Pt AuHg Tl Pb Bi Po At Rn 132.9 137.3 138.9 178.5 180.9 183.9 186.2 190.2 190.2 195.1 197.0 200.5 204.4 207.2 209.0 (210) (210) (222) 87 88 89 104 105 106 107 108 109 110 111 112 114 116 118 7 Fr Ra Ac~RfDb Sg Bh Hs Mt --- --- --- --- --- --- (223) (226) (227) (257) (260) (263) (262) (265) (266) () () () () () () http://pearl1.lanl.gov/periodic/ (1 of 3) [5/17/2001 4:06:20 PM] A Periodic Table of the Elements at Los Alamos National Laboratory 58 59 60 61 62 63 64 65 66 67 68 69 70 71 Lanthanide Series* Ce Pr NdPmSm Eu Gd TbDyHo Er TmYbLu 140.1 140.9 144.2 (147) 150.4 152.0 157.3 158.9 162.5 164.9 167.3 168.9 173.0 175.0 90 91 92 93 94 95 96 97 98 99 100 101 102 103 Actinide Series~ Th Pa U Np Pu AmCmBk Cf Es FmMdNo Lr 232.0 (231) (238) (237) (242) (243) (247) (247) (249) (254) (253) (256) (254) (257) ** Groups are noted by 3 notation conventions.
    [Show full text]
  • Ment 98), Einsteinium (Element 99), Fermium (Element 100), Mendelevium (Element Downloaded by Guest on September 26, 2021 472 PHYSICS: G
    VOL. 45, 1959 PHYSICS: G. T. SEABORG 471 of californium isotopes. The horizontal broken line labeled "0.02%" indicates the peak height for a group which would have that intensity relative to the total alpha particles. It is seen that the general background is considerably higher than this value, and, in fact, some of the peaks which are sketched in are hardly justifi- able in view of the scatter of the data. The bottom part of Figure 8 shows the same part of the spectrum taken under much improved conditions, as shown by the line illustrating the peak height of 0.02 per cent. All of the peaks are seen much more clearly and, in addition, one or two have showed up which were completely ob- scured under the other conditions. The principal change in technique which re- sulted in this improvement consisted of lining the interior of the spectrograph with very-low-atomic-number material which has the desirable effect of reducing low- angle scattering of alpha particles. In summary, we may say that during the past few years very important ad- vances in theory, as well as in experimental technique, are beginning to result in a systematic assignment of nuclear spectroscopic states and an interpretation of these states in terms of some detailed knowledge of nuclear structure. In this discussion, attention has been confined to one aspect of a very broad problem, namely, that having to do with spectroscopic states in the heavy-element region deduced from the alpha-decay process. There are many other experimental methods which are brought to bear on this problem, some of which have been touched upon in a peripheral sense in this discussion and others not mentioned at all.
    [Show full text]