On beyond uranium : journey to the end of the periodic table PDF
Preview On beyond uranium : journey to the end of the periodic table
On Beyond Uranium Science Spectra Book Series Series Editor: Vivian Moses, King’s College, London, UK Volume 1 The Key to the Future by John Cater Volume 2 On Beyond Uranium Journey to the end of the Periodic Table by Sigurd Hofmann This book is part of a series. The publisher will accept continuation orders which may be cancelled at any time and which provide for automatic billing and shipping of each title in the series upon publication. Please write for details. On Beyond Uranium Journey to the end of the Periodic Table Sigurd Hofmann London and New York First published 2002 by Taylor & Francis 11 New Fetter lane, London EC4P 4EE Simultaneously published in the USA and Canada by Taylow & Francis Inc, 29 West 35th Street, New York, NY 10001 Taylor & Francis is an imprint of the Taylor & Francis Group This edition published in the Taylor & Francis e-Library, 2003. © 2002 Taylor & Francis All rights reserved. No part of this book may be reprinted or reproduced or utilised in any form or by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying and recording, or in any information storage or retrieval system, without permission in writing from the publishers. Every effort has been made to ensure that the advice and information in this book is true and accurate at the time of going to press. However, neither the publisher nor the authors can accept any legal responsibility or liability for any errors or omissions that may be made. In the case of drug administation, any medical procedure or the use of technical equipment mentioned within this book, you are strongly advised to consult the manufacturer’s guidelines. Every attempt has been made to obtain permission to reproduce copyright material. If any proper acknowledgement has not been made, we would invite copyright holders to inform us of this oversight. British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library Library of Congress Cataloging in Publication Data A catalog record for this book has been requested ISBN 0-203-30098-X Master e-book ISBN ISBN 0-203-34540-1 (Adobe eReader Format) ISBN 0-415-28495-3 (hbk) ISBN 0-415-28496-1 (pbk) Contents Page Preface vii Acknowledgements viii Chapter 1 The landscape 1 Chapter 2 Elements created in stars 21 Chapter 3 Synthetic elements 27 Chapter 4 Elements made with light ion beams from ‘small’ cyclotrons 37 Chapter 5 Hot fusion and controversial discoveries: elements 102 to 106 43 Chapter 6 Cold fusion and ‘big’ cyclotrons 49 Chapter 7 The dream: uranium beams 65 Chapter 8 Models, cross-section and fusion 79 Chapter 9 New techniques – kinematic separators and position-sensitive detectors 89 Chapter 10 New elements and other stories: from bohrium to meitnerium 119 Chapter 11 The year 1988: a new beginning 151 Chapter 12 Three more elements: 110, 111 and 112 163 Chapter 13 Names mean more than numbers 175 Chapter 14 Attack on the domain of superheavies: elements 114, 116 and 118 183 Chapter 15 Epilogue 207 Bibliography 209 Name index 211 Subject index 213 Element index 216 Preface The nineteenth-century chemists did a marvellous job. From no more than a primitive understanding of chemistry and the nature of the elements in 1800, ten decades later chemical science knew of the probable existence of 92 ele- ments, from hydrogen the lightest to uranium the heaviest (although a few were so rare that they had not yet actually been identified). For nigh on 40 years we thought we knew what the Earth and everything on it and in it was made of. Then things started to change. Towards the end of the 1930s chemists and physicists began tentatively to discover elements beyond uranium, the ‘transuranics’. After World War II, with its startling developments in atomic physics leading both to atomic bombs and nuclear power stations, the pace began to quicken. When I started to study physics at the University of Darm- stadt in 1963, there were 103 elements known; now there are 116 and the number is still rising, albeit slowly. Looking for new elements is one of the strangest treasure hunts ever. You don’t find them in the rocks or in the sea or even in the stars. Most probably they really are not found in Nature at all except, perhaps, in a most transitory sense – here one moment, gone the next. In the sense that they do ‘exist’, they are to be found only in very carefully and precisely designed experiments in powerful nuclear tools of various sorts. Everything has to be set up all ready to detect them the instant they are formed because, for some of them, their survival time is to be measured in fractions of a second. Looking for new superheavy elements is what I spend my time doing – and I cannot imagine a more exciting branch of science. It is every bit as enthralling as it once was to explore an unknown continent but without mos- quitoes and hard camp beds. This book is about the search for elements never before known to humankind. The story takes a bit of telling; some of the concepts will be unfamiliar and the terminology new for you. But stick with it through the more difficult parts; it is worth staying the course until the end to find out why I remain so enthusiastic! Acknowledgements Extracts on pages 28, 31, 32, 33, 34, 39, 40, 41, 42 are taken from Seaborg, G.T. and Loveland, W.D. (1990) The elements beyond uranium. John Wiley and Sons, Inc., New York. This material is used by permission ofJohn Wiley and Sons, Inc. 1 The landscape Our world of elements is a landscape of minute particles, of protons and neutrons, of electrons and their counterpart, neutrinos. From that set of four sub-atomic particles a whole world is made, a world of planets and moun- tains, of rivers, lakes, shores and oceans, of flowers and trees and animals – and also of ourselves, we the thinking people. How is this possible – four tiny pieces and such a variety of con- sequences? Because the particles carry three secrets: the forces acting between them (which determine how the particles attract and repel each other, how they combine, and how they separate), the radiation which can be emitted from them when they move (this is the way we get the light from our sun), and the huge numbers of bricks available and how tiny each one is. Nowadays, many people have some understanding of chemistry and know about the existence of atoms and protons, and neutrons and electrons, although neutrinos remain something for specialists. Chemistry grew from alchemy; the alchemists, who, you will remember, were forever looking for the philosopher’s stone which would turn base metals into gold, with which their rulers never seemed to become sated. One of those alchemists, Johann Friedrich Böttger of Dresden, found porcelain instead of gold and was kept a prisoner in his laboratory so as not to betray the secret. All that looking at natural substances and experimenting with the ways in which they interacted with one another did, in the course of time, throw up a vast amount of empirical information which eventually demanded explanation. So chemistry became a modern experimental science, unlike the attempt at magic which had been the basis of the alchemy which had gone before. At about the same time, in the seventeenth century, the quality of astronomy reached a high standard. Sir Isaac Newton identified the universal law of gravitational force. Light and gases were investigated and answers sought to such apparently simple questions as the nature of air. The nineteenth century was the century of electromagnetic force, the force which acts between the charges of the fundamental particles. Michael Faraday in London coined the term ion for charged particles moving in an
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