143,99 €
Mehr erfahren.
- Herausgeber: John Wiley & Sons
- Kategorie: Fachliteratur
- Serie: ISTE Invoiced
- Sprache: Englisch
Researchers and students have not yet had access to a book which would enable them to trace the origins of the concepts that explain the behavior of materials under irradiation. This book fills the gap.
As far back as antiquity, the notions of purity and disorder have been evoked to explain the different properties of materials. It was geologists who developed the subject in the 19th century. Then, with the discovery of X-rays and radioactivity, disorder in materials became the domain of physicists and chemists. The first observations focused on the color changes of ionic crystals, then gradually all the techniques for characterising materials were used. However, questions about the resistance of the components of the first atomic piles to irradiation led to the development of irradiation studies.
This book describes the historical approaches to particle transport and defect creation mechanisms. Several chapters detail the history of irradiation of different types of materials: metals, semiconductors, iono-covalent insulators, polymers and radiolysis of water. The final two chapters deal with irradiation tools and applications.
Sie lesen das E-Book in den Legimi-Apps auf:
Seitenzahl: 495
Veröffentlichungsjahr: 2025
Ähnliche
Table of Contents
Cover
Table of Contents
Title Page
Copyright Page
Preface
1 Preliminary Remarks
1.1. References
2 Prerequisites for the Irradiation of Materials
2.1. Materials and purity, an old story
2.2. Discovering the particles behind irradiation
2.3. First irradiation experiments
2.4. Secondary effects of radiation
2.5. Chapter 2 references
2.6. References
3 Particle Transport
3.1. It all started with collision experiments
3.2. Slowing down in the matter
3.3. Particle stopping power
3.4. Particle range
3.5. Transport simulation
3.6. Channeling effects
3.7. Chapter 3 references
3.8. References
4 First Notions of Defects
4.1. First observations of defects
4.2. Notions of defects
4.3. Chapter 4 references
4.4. References
5 Defect Creation Mechanisms
5.1. Production of defects by irradiation
5.2. Determination of threshold displacement energy
5.3. Numerical simulations
5.4. Irradiation-induced sputtering
5.5. Chapter 5 references
5.6 References
6 Metals Under Irradiation
6.1. Notions shared with other disciplines
6.2. Creation of defects in metals by irradiation
6.3. Displacement threshold
6.4. Description of defects
6.5. Defect annealing
6.6. Chapter 6 references
6.7. References
7 Semiconductors Under Irradiation
7.1. First irradiation of semiconductors
7.2. Defect generation and counting
7.3. Diffusion in semiconductors
7.4. Chapter 7 references
7.5. References
8 Iono-covalent Insulators Under Irradiation
8.1. Iono-covalent materials under irradiation
8.2. Biographies of some of the chapter’s personalities
8.3. References
9 Polymers Under Irradiation
9.1. First irradiations of polymers
9.2. Research into degradation mechanisms
9.3. Radio-oxidation of polymers
9.4. Research and development, an active field
9.5. Chapter 9 references
9.6. References
10 Radiolysis of Liquids
10.1. Upstream of the notion of radiolysis
10.2. Activated water
10.3. Free radicals
10.4. Solvated electrons
10.5. Effects of the spatial structure of energy deposits
10.6. Radiolysis yields
10.7. Chapter 10 references
10.8. References
11 Irradiation Tools
11.1. Accelerators
11.2. Nuclear reactors
11.3. Recent developments
11.4. Chapter 11 references
11.5. References
12 Irradiation Applications
12.1. Medical applications
12.2. Food processing
12.3. Polymer irradiation applications
12.4. Semiconductor doping
12.5. Radiation resistance of electronic components
12.6. Ion track technology
12.7. Cultural and historical heritage materials
12.8. References
Conclusions
C.1. An active community
C.2. Future prospects
C.3. References
Index
End User License Agreement
List of Tables
Chapter 2
Table 2.1. A brief chronology
Chapter 3
Table 3.1. Comparison of air range measurements (Bragg and Kleeman 1905) to th...
Table 3.2. A brief chronology
Chapter 5
Table 5.1. Some experiments to determine threshold displacement energy
Chapter 11
Table 11.1. France’s main research reactors. Dates correspond to their first d...
List of Illustrations
Chapter 1
Figure 1.1. Calendar distribution of publications consulted, highlighting the ...
Figure 1.2. Trends in the geographical origin of publications. The rise of the...
Figure 1.3. Evolution of the average number of authors per publication, calcul...
Chapter 2
Figure 2.1. Statue of Theophrastus (Palermo Botanical Gardens). We owe this At...
Figure 2.2. Albertus Magnus, author of “De mineralibus”, a compilation on mate...
Figure 2.3. Partial reproduction of the table of contents of A.F. Cronstedt’s ...
Figure 2.4. Reproduction of a plate showing the different dodecahedron shapes ...
Figure 2.5. F. Hauksbee’s electric machine. The glass sphere, partially emptie...
Figure 2.6. N. Rouland’s electrostatic machine, an improved version of the one...
Figure 2.7. Otto von Guericke’s air pump. Its principle is similar to that of ...
Figure 2.8. The magnificent vacuum pump used by F. Hauksbee. This pump feature...
Figure 2.9. The mercury pump designed by Hermann Sprengel. As the mercury flow...
Figure 2.10. Diagram of the device used by J.J. Thomson to measure the effect ...
Figure 2.11. Device used by A. Becker to measure the effect of cathode rays on...
Figure 2.12. Rutherford’s experiment to verify the origin of pleochroic halos....
Figure 2.13. Breakdown of radiological accidents by field of radiation use (Né...
Figure 2.14. Abbé René Just Haüy.
Chapter 3
Figure 3.1. Drawing of Sir W. Thomson’s quadrant electrometer (Thompson 1905)...
Figure 3.2. Radioactive decay chain of 226Ra. At the beginning of the 20th cen...
Figure 3.3. Evolution of ionizations in the air of a radium source for differe...
Figure 3.4. Variation in the energy of α of radium C as a function of the rang...
Figure 3.5. Photographic plate showing the trajectories of α in air alone or b...
Figure 3.6. Left: velocity evolution of radium C alphas as a function of their...
Figure 3.7. Richard Whiddington’s device for measuring the energy loss of cath...
Figure 3.8. Diagram of the Geiger and Marsden device for studying α reflected ...
Figure 3.9. First measurement of the evolution of the alphas scattering angle ...
Figure 3.10. Elastic scattering of 210 eV electrons by helium (Mott 1929). Cur...
Figure 3.11. Schematic representation of the different range concepts (Lindhar...
Figure 3.12. Universal differential scattering cross-section for elastic colli...
Figure 3.13. Stopping power of some targets normalized to that of aluminum for...
Figure 3.14. Three volumes in the collection “The Stopping and Ranges of Ions ...
Figure 3.15. Comparison of simulated range distribution (Oen et al. 1963) with...
Figure 3.16. Screenshot of SRIM-2013 software: calculation of 8,500 helium tra...
Figure 3.17. Penetration depth of 50 keV 137Cs in aluminum. The asymmetrical n...
Figure 3.18. Projection on the (001) plane of three 5 keV Cu ion trajectories ...
Figure 3.19. (a) Transmission of 75 keV protons through a gold crystal as a fu...
Figure 3.20. Left: backscattering spectra in random and aligned [111] directio...
Figure 3.21. Ernest Rutherford, Nobel Prize in Chemistry 1908. Photo credit: N...
Figure 3.22. Hans Albrecht Bethe, Nobel Prize in Physics 1967. Photo credit: N...
Chapter 4
Figure 4.1. Two photographs linked to two major discoveries at the end of the ...
Figure 4.2. Schematic representation of the discharge tube used by Goldstein. ...
Figure 4.3. The beginning of Adolf Fick’s article on diffusion9 (Fick 1855)...
Figure 4.4. The different types of diffusion in a polycrystalline material (Me...
Figure 4.5. Samuel Colville Lind. Photo credit: AIP Emilio Segrè Visual Archiv...
Figure 4.6. György von Hevesy, winner of the 1943 Nobel Prize in Chemistry. Ph...
Figure 4.7. Walter Hans Schottky (1886–1976). Photo credit: AIP Emilio Segrè V...
Figure 4.8. Yakov Illich Frenkel (1894–1952) Physico Technical Inst. St Peters...
Chapter 5
Figure 5.1. Possible effects of high-energy radiation (after Burton (1947))
Figure 5.2. Schematic representation of vacancy production on a Taylor–Orowan ...
Figure 5.3. Schematic representation of the Klick model for the creation of F ...
Figure 5.4. Adiabatic potential curves of a Cl2 molecule. Curve C represents t...
Figure 5.5. Comparison of the number of displacements created in iron by a pri...
Figure 5.6. E1 trap production rate in germanium, normalized to 1 MeV as a fun...
Figure 5.7. Threshold energy as a function of primary ejection direction relat...
Figure 5.8. Frenkel pair stability domain in the (100) copper plane. Positions...
Figure 5.9. Distribution of vacancies and interstitials created by a 400 eV pr...
Figure 5.10. Atom trajectories initiated by an atom emitted at 65 eV (O atom) ...
Figure 5.11. Schematic representation of the damage created by a primary knock...
Figure 5.12. Schematic representation of an experiment to measure the velocity...
Figure 5.13. TEM observation of uranium atoms ejected by fission fragments and...
Figure 5.14. Fission traces obtained by post-irradiation of the collector and ...
Figure 5.15. Eugene-Paul Wigner. Photo credit: AIP Emilio Segrè Visual Archive...
Figure 5.16. Frédéric Seitz. Photo credit: AIP Emilio Segrè Visual Archives, P...
Chapter 6
Figure 6.1. Evolution of the annual number of publications with the keywords “...
Figure 6.2. The different types of dislocation according to Voltera, after (Hi...
Figure 6.3. Evolution of the electrical resistivity of three metals irradiated...
Figure 6.4. Resistivity evolution under neutron irradiation at 80°C of initial...
Figure 6.5. Disordered Cu3Au resistance versus time at 200°C and under a fast ...
Figure 6.6. Comparison of experimental and calculated displacement cross-secti...
Figure 6.7. The six possible interstitial configurations in a c.f.c. lattice: ...
Figure 6.8. Field ion microscopy of a platinum tip showing a vacancy in the [0...
Figure 6.9. Isometric drawing of a depleted zone constructed from the detectio...
Figure 6.10. Contact-mode atomic force microscopy of the surface of a graphite...
Figure 6.11. Diffuse scattering intensity measured at 4.5°K for aluminum near ...
Figure 6.12. Comparison of measured and calculated diffuse scattering intensit...
Figure 6.13. Annealing of the irradiation-induced increase in resistivity in c...
Figure 6.14. Target box for low-temperature electron irradiation (liquid nitro...
Figure 6.15. Numerical derivative of the isochronous annealing curve. The vari...
Figure 6.16. Copper face-centered cubic lattice with a body-centered interstit...
Figure 6.17. Isochronous annealing of a copper sample irradiated with 3.25 MeV...
Figure 6.18. Schematic representation of the different reaction pathways of a ...
Figure 6.19. Erwin Wilhelm Müller. Photo credit: Niels Bohr Library & Archives...
Chapter 7
Figure 7.1. Trend in the annual number of publications using the keywords “irr...
Figure 7.2. The semiconductor bombardment device described in the patent by Oh...
Figure 7.3. Evolution of conductance expressed in mho3 as a function of irradi...
Figure 7.4. Influence of helium ion energy on current-voltage characteristics ...
Figure 7.5. Acceptor site creation rate as a function of electron energy. The ...
Figure 7.6. Table taken from Loferski and Rappaport (1959). ELO: energy thresh...
Figure 7.7. Small recrystallized regions observed by transmission electron mic...
Figure 7.8. Representation of the A center. The unpaired electron is at the or...
Figure 7.9. High-resolution electron microscopy image of an oriented germanium...
Figure 7.10. Bright-field electron microscopy showing dislocations created by ...
Figure 7.11. Schematic representation of potential energy for two interstitial...
Figure 7.12. Right to left: Robert Walker, James Corbett and an unidentified p...
Chapter 8
Figure 8.1. Left: tracks due to fission fragments in mica, the two long obliqu...
Figure 8.2. Optical density, normalized by electron path length, compared with...
Chapter 9
Figure 9.1. Cathode ray irradiation device (Becker 1904). E: discharge tube, F...
Figure 9.2. Polymerization of methyl acrylate by irradiation with neutrons and...
Figure 9.3. Number of moles of gas emitted per mole of polyethylene (curve 1),...
Figure 9.4. Percentage of insoluble polythene as a function of irradiation dos...
Chapter 10
Figure 10.1. Device developed by Duane and Scheuer (1913a) for precise measure...
Figure 10.2. Left: device used by Hart and Boag to measure the transient optic...
Figure 10.3. Energy distribution between different ionization configurations: ...
Figure 10.4. Spatial evolution of chemical elements created by a 5 keV electro...
Figure 10.5. Hugo Fricke (1923).
Chapter 11
Figure 11.1. Principle of voltage transformation with potential fields. Figure...
Figure 11.2. Diagram of a cyclotron from Lawrence’s patent on the invention of...
Figure 11.3. Schematic diagram of Cockcroft–Walton and Van de Graff accelerato...
Figure 11.4. The 5.1 MV electrostatic generator in the former airship hangar (...
Figure 11.5. The electrostatic generator in its steel tank (Herb et al. 1935)
Figure 11.6. Copy published in Rose and Wittkower (1970) of the original paten...
Figure 11.7. ZOE atomic pile at the Centre d’Études Nucléaires de Fontenay-aux...
Figure 11.8. Open pool of the 7 MW TRITON reactor at CEA Fontenay-aux-Roses. T...
Figure 11.9. Low-temperature (10K) infrared irradiation and absorption measure...
Figure 11.10. Enrico Fermi and Ernest O. Lawrence (right) in 1930
Chapter 12
Figure 12.1. Lid of a can of Tho-radia powder containing 0.01 μg radium bromid...
Figure 12.2. Painting by Georges Chicotot, 1917, depicting the first trials of...
Figure 12.3. Half-section view of D.A. Gillett’s apparatus for preserving orga...
Figure 12.4. Irradiation system developed at Bell Telephone Laboratories. The ...
Figure 12.5. Schematic representation of a p-n junction in a semiconductor (Sh...
Figure 12.6. Optical devices of the first 150 keV Extrion implanters (after Ro...
Figure 12.7. Leading implanter manufacturers. Arrows marked with an L indicate...
Figure 12.8. Fission fragment tracks in mica (Silk and Barnes 1959)
Figure 12.9. Examples of cosmic ray tracks inside an Apollo space helmet. (A) ...
Figure 12.10. Diagram of a heavy-ion nuclear track filter production line. A w...
Conclusions
Figure C.1. Number of publications with the terms “irradiation AND material AN...
Figure C.2. Number of publications containing the terms “irradiation AND mater...
Guide
Cover Page
Table of Contents
Title Page
Copyright Page
Preface
Begin Reading
Conclusions
Index
WILEY END USER LICENSE AGREEMENT
Pages
iii
iv
xi
xii
xiii
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
195
196
197
198
199
200
201
202
203
204
205
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
299
300
301
302
303
SCIENCES
Materials Science, Field Director – Jean-Pierre Chevalier
Metallurgy, Subject Head – Jean-Pierre Chevalier
A Historical Approach to Materials Under Irradiation
Serge Bouffard
First published 2025 in Great Britain and the United States by ISTE Ltd and John Wiley & Sons, Inc.
Apart from any fair dealing for the purposes of research or private study, or criticism or review, as permitted under the Copyright, Designs and Patents Act 1988, this publication may only be reproduced, stored or transmitted, in any form or by any means, with the prior permission in writing of the publishers, or in the case of reprographic reproduction in accordance with the terms and licenses issued by the CLA. Enquiries concerning reproduction outside these terms should be sent to the publishers at the undermentioned address:
ISTE Ltd27-37 St George’s RoadLondon SW19 4EUUK
www.iste.co.uk
John Wiley & Sons, Inc.111 River StreetHoboken, NJ 07030USA
www.wiley.com
© ISTE Ltd 2025The rights of Serge Bouffard to be identified as the author of this work have been asserted by him in accordance with the Copyright, Designs and Patents Act 1988.
Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s), contributor(s) or editor(s) and do not necessarily reflect the views of ISTE Group.
Library of Congress Control Number: 2024950249
British Library Cataloguing-in-Publication DataA CIP record for this book is available from the British LibraryISBN 978-1-78945-221-1
ERC code:PE4 Physical and Analytical Chemical Sciences PE4_14 Radiation and Nuclear chemistryPE5 Synthetic Chemistry and Materials PE5_1 Structural properties of materials
Preface
The history of science generally focuses on major scientific breakthroughs or personalities who left their mark. When it comes to the history of research on materials under irradiation, there are very few documents providing a historical overview of this research. A few short texts do, however, provide a starting point for developing this history. These include articles by Seitz (1952), Dienes (1953), Billington and Crawford (1961), Seeger (1980), Quéré (1993) and Ewing (1994). Research into materials under irradiation is closely linked to related fields, which have been the subject of numerous reports. These include, on the one hand, the discoveries of X-rays and radioactivity (Pais 1986; Fernandez 2006) and, on the other hand, the development of materials science and solid state physics, with names like F. Seitz, F. Bloch, N.F. Mott, R.E. Peierls and J. Bardeen. These fields are well documented; see, for example, Mott’s (1980) book on the beginnings of solid state physics. In addition, the “irradiation of materials” community has benefited greatly from its proximity to the “dislocation” community (F.R.N. Nabarro, W.G. Burger, F.C. Frank, A.H. Cottrell and J. Friedel). Particle transport in matter, a more specialized field than material damage, has also been the subject of reviews; see, for example, the introduction to the book “The Stopping and Range of Ions in Matter” (Ziegler et al. 1985).
The aim of this book is therefore to provide researchers, engineers and students with a historical approach to materials under irradiation, presenting the appearance and development of the various concepts, and the experiments that led to their emergence. These theories and experiments are presented only in a broad outline, and readers that would like to know all their subtleties will need to study the original texts. It should also be noted that the lack of information on most of the actors involved makes it difficult to flesh out this story.
This book is a project which, from the initial research of articles to the printed book, has taken more than 10 years to complete, albeit on a part-time basis. Having worked on a corpus of some 1,690 articles, it was reasonable to bring it to a close when some aspects were only imperfectly covered. Moreover, I am an experimental physicist, and experiments are certainly presented in greater detail than theoretical approaches. Finally, as Jonah writes in
A Short History of the Radiation Chemistry of Water
:
There will certainly be omissions, misattributions and misunderstandings of the past. This is unavoidable because first, I wasn’t there and second, I have been influenced by my surroundings and the people that I have known (Jonah 1995).
This book would not exist without the people who guided my first steps in research, Gérard Maeder, professor at ENSAM (École Nationale Supérieure des Arts et Métiers), and Libéro Zuppiroli, my thesis supervisor. Nor would it have been possible without the colleagues I enjoyed working with, Florence Rullier-Albenque, and László Forró at SESI1 (Section d’Études des Solides Irradiés, CEA Fontenay-aux-Roses), my colleagues at CIRIL2 (Centre Interdisciplinaire de Recherche avec les Ions Lourds, Caen) and, especially, Emmanuel Balanzat. I would like to thank the CEA and CNRS for their documentation service, which enabled me to find practically all the documents online. Thanks also to Chantal Brassy of CIMAP in Caen, who provided me with many articles.
Serge BouffardDecember 2024
References
Billington, D.S. and Crawford, J.H. (1961).
Radiation Damage in Solids.
Princeton University Press, Princeton, NJ.
Dienes, G.J. (1953). Radiation effects in solids.
Annual Review of Nuclear Science
, 2, 187–220.
Ewing, R.C. (1994). The metamict state: 1993 – The centennial.
Nuclear Instruments & Methods in Physics Research Section B: Beam Interactions with Materials and Atoms
, 91, 22–29.
Fernandez, B. (2006).
De l’atome au noyau : une approche historique de la physique atomique et de la physique nucléaire.
Éditions Ellipses, Paris.
Jonah, C.D. (1995). A short history of the radiation chemistry of water.
Radiation Research
, 144(2), 141–147.
Mott, N.F. (1980). The beginning of solid state physics
. Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences
, 371(1744).
Pais, A. (1986).
Inward Bound: Of Matter and Forces in the Physical World.
Clarendon Press, Oxford.
Quéré, Y. (1993). Radiation effects in solids: A brief history.
Solid State Phenomena
, 30(31), 1–6.
Seeger, A.K. (1980). Some recollections of the radiation damage work of the 1950s.
Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences
, 371, 165–172.
Seitz, F. (1952). Radiation effects in solids.
Physics Today
, 5(6), 6–9.
Ziegler, J.F., Biersack, J.P., Littmark, U. (1985).
The Stopping and Range of Ions in Solids.
Pergamon Press, New York.
Notes
1
Now LSI (Laboratoire des Solides Irradiés).
2
Now known as CIMAP (Centre de recherche sur les Ions, les Matériaux et la Photonique).
1Preliminary Remarks
The essential difference between a physics or chemistry book and a historical study lies in the accuracy and completeness of the sources. Any physics or chemistry article usually begins with a short introduction describing the background to the research, without necessarily going back to the original work. Furthermore, it is questionable whether all the articles cited have actually been read. For example, nearly all theses on material irradiation refer to an article by Kinchin and Pease for the creation of defects, more out of tradition than necessity. On the other hand, a historical approach must necessarily go back to the emergence of the idea, the concept, etc., which poses a number of problems for an amateur historian who, in order to be as close as possible to the truth, comes up against several difficulties. In the 19th century, articles contained few references to previous works and ideas were often germinated collectively, hence their appearance in several laboratories. Also, many early articles were written in the authors’ own languages (in German, or Swedish, for example; fortunately, translation software makes it possible to understand them). Moreover, during the Second World War, a time of intense discoveries in the field of irradiation, advances were only disseminated in confidential internal reports. Added to this was the difficulty of obtaining certain reports, articles and books. Despite all this, writing this book required me to consult some 1,700 documents and translate around a hundred from German, only to cite 620 of them in this book.
The number of articles collected is nevertheless sufficient to extract some information on the evolution of the subject, bearing in mind that this corpus is dependent on the way in which I have traced the history of the concepts. The more difficult it is to find the source, the more articles there will be on the subject. Nevertheless, Figure 1.1 shows two key dates for the irradiation of materials: around 1900, when the discoveries of X-rays and radioactivity opened up the field of irradiation, and around 1940, when the Manhattan Project and the first nuclear reactors created a strong demand for scientific and technological data. The decline in the number of articles from the 1960s onwards does not correspond to a reduction in activity, but to the fact that the main concepts were well known.
Figure 1.1.Calendar distribution of publications consulted, highlighting the two key dates (1900 and 1950) in research on the irradiation of materials.
Figure 1.2.Trends in the geographical origin of publications. The rise of the United States can be seen as early as the 1920s, while the Second World War considerably reduced the importance of Germany, the United Kingdom and France.
Figure 1.2 shows the geographical distribution of those involved in this research. In the 19th century, advances came first from Germany, then from the UK and France. By the 1910s, Germany and the UK were competing with the United States. By the end of the Second World War, the situation had changed radically. The United States accounted for around two-thirds of all publications, while German research had virtually disappeared, although it would regain significant influence from 1975 onwards. The importance of France from the 1960s onwards is certainly overestimated, thanks to a better knowledge of the actors, most of whom I have come across during my career. Other countries that have contributed to our understanding of the effects of irradiation include Japan, Canada, Hungary and Russia, followed by Poland, Sweden, Holland, Australia, Spain and many others.
Figure 1.3.Evolution of the average number of authors per publication, calculated on the basis of 1,690 references grouped together for this work. Before 1900, the vast majority of publications were signed by a single author. The solid line is a guide for the eye, adjusted for exponential variation
Figure 1.3 shows the average number of authors per article. Until 1900, this number remained constant at around 1.1 authors per article, then rose steadily to reach three in 2000. This evolution is consistent with the evolution of research organization described by Krzysztof Szymborski in “The Physics of Imperfect Crystals – A Social History” (Szymborski 1984). He divides this history into three periods. First, research was carried out by independent researchers, often from the aristocracy. The notion of a research laboratory did not exist. The signatures on articles were simply “W.C. Röntgen”, “Note de H. Becquerel” or “by William Crookes, Fellow of the Royal Society “or, more precisely, “by J.J. Thomson, M.A., F.R.S., Cavendish Professor of Experimental Physics, Cambridge”. The number of people who made a major contribution in this period remained limited to around 30, including E. Goldstein, C. Doelter, J.J. Thomson, E. Rutherford, W.H. Bragg, P. Curie, J. Frenkel and K. Przibram.
Next came the formation of schools of thought around a single personality, usually at a university. Examples include the Cavendish Laboratory at Cambridge University, home to eight Nobel Prize winners including J.J. Thomson, E. Rutherford and W.L. Bragg; the Physical Institute at Göttingen University, with N. Born, R.W. Pohl and J. Frank; the Institut für Radiumforschung, Wien, with K. Przibram, the Leningrad Institute of Physics and Technology with A. Joffe and J. Frenkel and many others.
Finally, the last stage developed by Szymborski is entitled “emergence of speciality”. In the case of irradiated materials, this stage appeared during the Second World War with the Metallurgical Laboratory at the University of Chicago and the creation of nuclear research centers: Oak Ridge National Laboratory (1943) in Tennessee, Brookhaven National Laboratory (1947) in New York State (USA), Chalk River Nuclear Laboratories (1942) in Ontario (Canada), Atomic Energy Research Establishment (1945) in Harwell, Oxfordshire (United Kingdom), Centre d’Études Nucléaires de Fontenay aux Roses (1946) and Saclay (1947) (France), Kernforschungsanlage Jülich GmbH (1956) and Forschungszentrum Dresden–Rossendorf (1956) (Germany).
Before delving into the history of materials under irradiation, we will take a look at what led to the emergence of this discipline: the notions of impure or disordered materials, instrumental developments in high-voltage and vacuum techniques and, of course, the discoveries of X-rays, electrons and radioactivity.
1.1. References
Szymborski K. (1984). The physics of imperfect crystals – A social history.
Historical Studies in the Physical Sciences
, 14(2), 317–355.
2Prerequisites for the Irradiation of Materials
By modifying the properties of certain materials, natural irradiation has long posed a problem for geologists. Why do materials with the same chemical composition and the same angles between their faces have different properties, such as the more or less birefringent nature of crystals? We now know that the origin lies in self-irradiation due to the presence of actinides. Thus, the notions of perfect/imperfect, pure/impure, ordered/disordered have been part of the preoccupations of different civilizations from very early on.
2.1. Materials and purity, an old story
2.1.1. Materials and disorder in ancient history
It was in a still young universe that the first particle–material interactions took place, but it was not until 700 million to one billion years later that the first generations of end-of-life stars dispersed the products of their nucleosynthesis, creating elements heavier than iron in supernova explosions. The first materials were then formed by the condensation of these atoms. Cosmic radiation and the radioactivity of nucleosynthesis elements were intense sources of irradiation. Much later, around a young star, planet Earth had the brilliance of having the right initial mixture and a temperature compatible with carbon chemistry, providing a favorable environment for the emergence of life. Here again, irradiation certainly helped organic chemistry to explore the possibilities. The appearance of life on Earth is estimated at 3.5 billion years ago in an environment that was far more radioactive than it is today. The ratio 235U/238U then exceeded 11% (currently 0.7%). Note that 1.5 billion years later, this ratio was still close to 3.5%, enabling the divergence of the natural reactors at Oklo (Gabon), albeit under very specific conditions of uranium concentration and presence of water (Bodu et al. 1972; Neuilly et al. 1972). They operated for several hundred thousand years.
The first hominids appeared in the Paleolithic era, some 3.3 million years ago. Then, as evolution did its work, knowledge of materials and, above all, the ability to modify them enabled hominids to distinguish themselves from other living beings. The first manufactured mineral was probably flint1 or obsidian2, whose conchoidal fractures, obtained by percussion, form sharp edges. Using an empirical approach, prehistoric man selected flint and the properties of the nanometric texture of chalcedony, combined with impurities. Much more recently, metals took social organization a step further, copper and gold at first, but their mediocre mechanical properties practically limited their use to objects of worship and social distinction. Alloy synthesis was the great breakthrough between the 5th and 3rd millennium before the current era (BCE). In particular, bronzes, binary copper–tin alloys, demonstrate very good mechanical strength and have a lower melting point than copper. They can therefore be processed even with rudimentary furnaces. When working with alloys, the aim is to master the microstructure. Improvements in furnaces enabled higher temperatures to be reached and the development of iron metallurgy (around 1,100 BCE). The great advantage of iron over bronze is its greater mechanical strength, while at the same time being ductile when hot, so it can be worked by hammering. Furthermore, mankind learned fairly quickly how to modify the mechanical properties of iron by adding carbon. These latest technological developments profoundly altered the organization of society, whose economy developed through the specialization of production and workplaces, increased agricultural yields, the emergence of merchants, etc.
In the last millennium BCE, we were a long way from materials under irradiation. Nevertheless, in Greco-Roman antiquity, the notions of disorder, defect, amorphous, etc., without being clearly named, were underlying in mineralogical works. Thus, the Athenian philosopher Theophrastus (371–288 BCE) in his treatise on stones, a veritable inventory of these materials and their origins, often attributed the qualifiers “true”, “bad”, “indefinite” and “pure” to minerals. For example, he wrote: “There are still in the fossil kingdom certain remarkable Earths which are formed in a purer and more homogeneous manner than the others” (Theophrastus, 1754 [4th century BCE], author’s translation). Theophrastus was a disciple and friend of Aristotle. On Aristotle’s death, he succeeded him as head of the Lyceum, the philosophical school founded around 335 BCE by Aristotle.
Figure 2.1.Statue of Theophrastus (Palermo Botanical Gardens). We owe this Athenian philosopher a veritable inventory of stones and their origins
In Rome, three centuries later, Pliny the Elder’s Naturalis Historiæ included book XXXVII3 on precious stones – what we would today call an encyclopedia. In addition to describing Roman society’s relationship with materials, paragraphs were devoted to their properties. In the case of diamonds, for example, he wrote: “All these diamonds are tested on the anvil, and they resist blows so well that the iron rebounds and the anvil itself cracks. Indeed, their hardness is incredible: moreover, they triumph over the action of fire and never heat up; it is this indomitable strength that has given them the name they bear in Greek4” (Pliny the Elder 1830 [79 BCE], author’s translation). Their properties are somewhat idealized, and I would not advise anyone who owns a diamond to test its resistance to hammer and fire. But he also indicated that, because of its great hardness, diamond dust could be used to cut and polish other precious stones.
During the Middle Ages, scientific work continued, combining philosophy, theology, astronomy and alchemy. In the 13th century, we find a remarkable figure, the Dominican Albertus Magnus (Bavarian from the Holy Roman Empire), also known as Albert de Lauingen. He taught in Rome and Paris, where he was so successful that he was obliged to hold his lectures in the open air on a square that came to be known as Place Maître-Albert (this square still exists today as Place Maubert, an alteration of the original name). His output was enormous: more than 70 authentic works on theology, Aristotle, animals, plants, women, meteorology and minerals. This work on minerals was produced between 1248 and 1262, and was printed in Latin in 1569 (Magnus 1569); and, more recently, translated into English with commentary (Wickoff 1967). The originality of this work lies in the fact that, unlike what had been or would be published in subsequent centuries, his work was not a simple compilation of the various minerals, but an attempt to explain their properties. Thus, we find chapters entitled “The cause of the different colors of gemstones”, “The cause of differences in the hardness of stones” and “The cause of the porosity and compactness of stones, as well as of their heaviness and lightness”. Nevertheless, the content often remains at the philosophical or assertive level: “Let us say, therefore, that the general cause of hardness is dryness”.
Figure 2.2.Albertus Magnus, author of “De mineralibus”, a compilation on materials and their properties. Image: Posthumous fresco by Tommaso da Modena (1352, Treviso).
The Renaissance, with its questions about the world around it and major discoveries such as printing, paved the way for the scientific revolutions of modern times. Descriptions of materials became increasingly precise. Examples include De re metallica (Agricola 1556), an impressive compilation of 16th-century knowledge on the metallurgy of various metals, published in 1556 by Georgius de Agricola (real name Georg Bauer, a Saxon from the Holy Roman Empire).
A few centuries later, Baron Axel Fredrik Cronstedt, a Swedish chemistry enthusiast, discovered nickel and recognized stilbite as belonging to a new class of minerals: zeolites. In 1758, he published an essay on a system of the mineral kingdom, Försök till Mineralogiens eller mineral-Rikets upställing (Cronstedt 1758).
Figure 2.3.Partial reproduction of the table of contents of A.F. Cronstedt’s essay on a mineral kingdom system (Cronstedt 1758) as translated by G. von Engeström (Von Engestrom 1770).
Published in Swedish, it was translated into English 12 years later (Von Engestrom 1770). Materials belonging to the mineral kingdom are divided into four categories: earths, flammables, salts and metals. A.F. Cronstedt classified around 360 minerals and, for each one, gave its origin and main properties, appearance, hardness, brittleness, fusion, chemical attack, etc. In the table of contents (Figure 2.3), he considers two main categories of quartz, pure and impure, with subdivisions based mainly on visual appearance, color, transparency, inclusions and origin. He also classifies diamonds in the “Siliceous” category and rubies in the “Diamond” category. Cronstedt, who was certainly at the origin of modern mineralogy, published his book anonymously:
[…] for treating Mineralogy in a systematical manner; a study to which I have with so much pleasure applied myself. It is not done from the desire of novelty, and still less from contempt of those systems, which Swedish gentlemen in particular, very deservedly, though chiefly on the same principles, have heretofore generally pursued. I have thought proper to conceal my name…
The 18th century, the Age of Enlightenment, saw the emergence of numerous scientists and philosophers, many of whom made decisive contributions to our understanding of the laws that govern the world: Ampère, Bernoulli, Coulomb, Euler, Franklin, Galvani, Lagrange, Laplace, Lavoisier, Legendre, Newton, Venturi, Volta, Watt, among others. Alongside mathematics, physics and chemistry and mineralogy also made significant progress. The idea that the shape of crystals reflects their internal organization was already a remarkable insight that paved the way for future crystallographic studies. Without being developed, this idea is present in the article Crystal, crystaux ou crystallisation in Diderot and d’Alembert’s Encyclopédie (1751–1772):
[…] one names crystal or crystals all the mineral substances which take of themselves & without the help of art, a constant and determined shape: there are therefore as many different species of crystals as there are substances… & take a distinctive form by which it is easy to recognize them (Thiry d’Holbach 1754, author’s translation).
In the same spirit, Abbé Jean-Baptiste Romé de l’Isle went even further, describing the geometric shape of a very large number of materials (Romé de l’Isle 1783). The example of rock crystal (quartz) is shown in Figure 2.4: “The primitive figure of the rock crystal is a dodecahedron, formed by two hexahedral pyramids with isosceles triangular planes, joined base to base…”. He then gives possible variants, introducing truncations. In his discussion of the results, he demonstrates a very direct critical spirit:
[…] I confess that these experiments will always leave something to be desired, as long as we have not succeeded in regenerating quartz or rock crystal, by directly combining the principles of which it is said to be composed. This is also what Messrs Achard & Bergman claim to have done; but as the experiments of the former have hitherto been repeated without success, & as the unique experiment of the latter leaves doubts as to the nature of the crystals which were its product, it is appropriate to suspend judgment, until one or other of these skilful chemists has put the seal of evidence on his discovery (Volume 2, p. 55, author’s translation).
Figure 2.4.Reproduction of a plate showing the different dodecahedron shapes with truncated planes after J.B. Romé de l’Isle (Romé de l’Isle 1783)
Many geologists were also interested in the systematic identification and classification of minerals. However, these considerations on the internal structure of minerals were slow to spread among geologists and mineralogists. Thus, in the 1763 edition of his comprehensive dictionnaire oryctologique5, Swiss geologist Elie Bertrand describes minerals as formed from primitive principles, “Earths and sands serve to form ROCKS…”. However, in discussing the difference between pyrite and iron marcasite, he refers to the internal structure of these materials: “Amorphous pyrite is according to them [the alchemists] the marcasite of iron” and further, in a contradictory manner, “We believe to reserve the word marcasite to designate an angular, crystallized, faceted form of pyrite” (Bertrand 1763, p. 329, author’s translation). Finally, we should mention the work of Abraham Gottlob Werner, a Saxon from the Holy Roman Empire. He developed a methodological system that turned geology into a systematic science. In 1774, he published the first modern textbook on descriptive mineralogy: Von den äusserlichen Kennzeichen der Fossilien (On the external characteristics of minerals) (Werner 1774).
At the beginning of the 19th century, the Frenchman René Just Haüy described the organization of minerals with greater rigor. To do so, he measured the angles between crystal faces with great precision. He hypothesized that minerals are made up of elementary molecules bound together by affinity. Elementary molecules assemble into integral molecules, the smallest element that preserves the nature of the mineral. The assembly of integrating molecules composes a regular body, the crystal, and gives it its external form (Haüy 1822). He listed 1,040 crystalline forms.
The notion of disorder in minerals only emerged in the 19th century, initially through the observation of differences in the behavior of materials of the same composition. In 1815, Jöns Jacob Berzelius wrote of gadolinite6 of different origins:
All of them, however, have a common property that I have not yet seen described in mineralogical handbooks, and which Dr. Wollaston recently pointed out to me in London: it consists of the fact that, if a piece of gadolinite is heated slowly and evenly by the flame of a blowtorch, it promptly reddens at a certain temperature, as if it were on fire, and the incandescence spreads all the more rapidly the more evenly it has been heated (Berzelius 1815, author’s translation)7.
The phenomenon reported to Berzelius by Wollaston8 corresponds to the release of energy during the recrystallization of amorphous gadolinite. This explanation would not be known until many years later (Gibson and Ehlmann 1970).
Although Alfred Des Cloiseaux and Alexis Damour were not concerned with defects or amorphization, they did show that materials of the same chemical composition can have different properties (Des Cloizeaux and Damour
1860
). Their study focused on several materials, including gadolinite. The latter material, of fifteen different origins for this study, apparently formed a homogeneous group, but some behaved like a birefringent crystal, while others appeared to be composed, in variable proportions, of a birefringent component embedded in a mono-refractive material. After the same observations on allanite
9
, they concluded:
We can see from our observations on Allanites that some samples behave in polarized light like a birefringent crystallized body with two axes, while others do not enjoy double refraction. The latter must be regarded as amorphous substances that have taken the place of epidote crystals whose shape is very close to that of Allanite…
Further, they noted that
[…] Allanites and orthites, whether or not they possess double refraction, always offer the same external form (Des Cloizeaux and Damour 1860).
The polarization of light has been known since the early 19th century. In 1860, no one could have imagined the origin of these differences. This French-language paper on the analysis of 44 origins or types of material represents a very extensive work on minerals, mostly from private collections (Adam, Damour) or donations (Berzelius, Prince Napoleon). Curiously, while this study was signed with both names, some paragraphs are written in the first person singular, in which case Des Cloizeaux is the author.
In a presentation to the Académie des Sciences de Paris (Paris Academy of Science) on Monday January 18, 1864, M.A. Damour discussed the density of zircons10, which, despite identical composition, varies from 4.04 to 4.67 g/cm3. By heating these zircons to a high temperature (red-white), whatever the initial density, it converges to a single value. He then hypothesized that zircons have two allotropic states11 (Damour 1864).
In 1890, W. Petersson published a long article summarizing gadolinite research and presenting new chemical analyses (Peterson 1890). It includes a description of Berzelius and Wollaston’s experiment, followed by an attempted explanation taken from a publication by Scheerer (1840), which assumes that gadolinite solidifies from molten magma. When cooling is very slow, the molecules choose the loosest system, whereas rapid cooling results in a different molecular arrangement. Three years later, in his classification of minerals, Norwegian geologist Waldemar Christofer Broegger differentiated between crystalline and amorphous materials and classified the latter into two categories: porodine amorphous formed by slow cooling of gelatinous substances and hyaline amorphous formed by rapid cooling from the molten state. However, he was obliged to add a third group, materials which, while having a shape reminiscent of crystals, have isotropic optical properties, a lower density than normal, conchoidal-type fractures. He proposed to call this category of materials metamict. He first used the word in an article on amorphous materials in the Danish encyclopedia Salmonsens Store Illustrere Konversations Lexicon (Broegger 1893). W.C. Broegger postulated that metamict minerals existed as perfect crystals, but were probably disordered by external agents because their structure is relatively unstable:
Many of these minerals are even known only as amorphous, but from their original formation they have retained their outer crystalline boundaries (e.g. euxenite, thorite, etc.); others are amorphous in some deposits and crystalline in others unchanged. In the case of gadolinite, it has been proven that the amorphous gadolinite, when heated to annealing, resumes its original crystal structure and becomes birefringent (translation from Danish by the author).
Swedish mineralogist Axel Hamberg was probably the first to suggest that metamictization is caused by α particles emitted by the radionuclides uranium and thorium included in minerals, but this was not until 1914 (Hamberg 1914). Rodney Ewing’s article The Metamict State: 1993 – The Centennial is a very good introduction to the evolution of knowledge about the metamict state (Ewing 1994).
2.2. Discovering the particles behind irradiation
The notion of disordered materials therefore predates the first studies of intentionally irradiated materials. It was only with the discovery of energetic particles, the observation of their effects on materials and the development of structural analysis tools that real progress was made in understanding the phenomena observed. In this context, the discoveries of X-rays and natural radioactivity were major events. However, before describing the first irradiation experiments, let us take a brief look back at the succession of conceptual and experimental advances that made these discoveries possible. The key element in the case of X-rays is the discovery of cathode radiation, which required knowledge of high-voltage generation and the notion of vacuum. We will take a look at the history of these two techniques, starting with electricity.
2.2.1. High-voltage generation
The word electricity comes from the name of a fossilized oleoresin: amber named in Greek ἤλεκτρον (elektron). Its electrostatic properties were observed by Thales of Miletus around 600 BCE and succinctly described by Theophrastus a century later (Theophrastus 1754 [4th century BCE]).
Figure 2.5.F. Hauksbee’s electric machine. The glass sphere, partially emptied of air and set in rotation, is electrified by friction. Fine wires indicate the orientation of the field lines (Hauksbee 1709).
In 1775, in his history of electricity, Joseph Priestley credited Guilielmi Gilberti (William Gilbert) with inventing modern electricity, even though he lived in the late 16th–early 17th century (Priestley
1775a
). The London physicist carried out numerous experiments on magnets and electrifiable materials. He showed that amber’s property of attracting light objects when rubbed could be generalized to many materials (diamond, sapphire, beryl and glass). He wrote that the electrical effect was stronger when the air was dry, which seems logical, but more unlikely when the wind blows from the east or north. In 1600, he published his observations in what may be considered the first book on experimental physics:
De magnete
(Gilberti
1600
).
The first voltage generators were electrostatic machines whose electrification was achieved by friction (triboelectricity). In 1660, the Prussian Otto von Guericke, fortification engineer and mayor of Magdeburg, generated electricity by rubbing a rotating ball of sulfur. He mainly studied the attraction/repulsion phenomena between electrified bodies, and observed an electric light that he likened to that emitted when sugar is crushed in the dark.
Figure 2.6.N. Rouland’s electrostatic machine, an improved version of the one by C.L. Walckiers de Saint Amand. In this machine, a precursor of the Van de Graaff generators, charges were transported by a silk ribbon and collected by cushions to generate a high voltage (Brenni 1999)
The first real electric machine was built by Francis Hauksbee (see section 2.5.2). Seeking to produce light by friction, he designed a device consisting of a glass sphere rotating around an axis, in which a partial vacuum could be created (Figure 2.5). When the sphere was set in motion, friction with a hand electrified the sphere, and he observed the electric field lines using fine wires running along these field lines (Hauksbee 1709). During the 18th century, machines made progress, notably by increasing the size of glass spheres or cylinders, improving glass quality and, above all, electrical machines themselves. The latter were capable of producing sparks over distances of around 18 inches, that is, for dry air, a voltage of the order of 450 kV! For more details on this exciting period, see Joseph Priestley’s The History and Present State of Electricity, published in 1775 (Priestley 1775a).
In 1784, Charles-Louis Walckiers de St Amand developed an electric machine in which charges were carried by an endless silk ribbon. The charges were deposited by cushions covered with cat skins or wool. The machine had impressive dimensions, with a silk taffeta ribbon five feet wide by 25 feet long (1.5 × 7.6 m2). It was presented to the Royal Academy of Sciences in Paris (Walckiers de St Amand 1784). From its very first tests, this generator became one of the best machines based on glass loading capability. It was the forerunner of the Van de Graaff generator. However, this machine had the disadvantage of its size, so it was not developed further, despite a few proposals for vertical versions, notably in Germany, by Gottlieb Christian Bohnenberger. It is interesting to note that it was not until 1800 that the electric battery was invented by Alessendro Volta. In 1872, following the same idea as C.L. Walckiers de Saint Amand, Augusto Righi designed a machine in Bologna to create a strong electric field by adding small electric charges. An endless Indian rubber tube was mounted on two pulleys. Rings of copper wire wound at regular intervals on the tube transported the charges deposited near the earthed pulley. They were discharged by means of a contact spring inside a sphere which acquires a very high charge, even though the initial charge in the influence body was very low. The principle of today’s Pelletron closely resembles this device. The imagination of physicists and engineers has produced a large number of different devices, all based on the transport of charges deposited by influence. John Gray’s book (Electrical Influence Machines: A Full Account of Their Historical Development, and Modern Forms, With Instructions for Making Them) gives a fairly complete description on pages 188–190 (Gray 1890).
Michael Faraday’s discovery of electromagnetic induction in 1831 opened up a new way of creating high voltages: induction coils. This type of electrical transformer produces high-voltage pulses from low-voltage direct current. The direct current in the primary coil is periodically interrupted by a vibrating mechanical contact to create the flux changes required to induce a voltage in the secondary coil. This device was invented simultaneously in 1836 by American physicist Charles Grafton Page (1837) and Irish scientist Nicholas Callan (1836). This question of anteriority of discovery seems particularly important to C.G. Page. The tone is set by the title of his book History of Induction. The American Claim to the Induction Coil and its Electrostatic Development, in which he devotes 46 pages to proving its anteriority:
Prof. Callan’s description of this coil is found in the London and Edinburg Philosophical Magazine for December, 1836. This communication is dated August 23, 1836. Prof. Page’s communication to Sill’s Journal was dated May 12th , 1836, and its postscript June 8th, 1836. It did not appear in that Journal until the January No. for 1837; […] These dates and peculiar facts settle the question of priority in favour of Prof. Page, beyond controversy (Page 1867).
Sill’s Journal, in which Page publishes, is short for Silliman’s Journal, the name often given in the early days to The American Journal of Science and Arts, which Benjamin Silliman founded in 1818.
Figure 2.7.Otto von Guericke’s air pump. Its principle is similar to that of a bicycle pump, in which the valve would have been replaced by tap I, opened and closed to the rhythm of the piston’s movement (de Guericke 1672).
In 1851, Heinrich Daniel Ruhmkorff, a German-born Parisian, perfected the induction coil by improving the insulation of the secondary windings and segmenting the soft-iron core to reduce eddy currents. This generator, known as the Ruhmkorff coil, was capable of producing electric arcs 30 cm long. It was used in the experiments that led to the discovery of X-rays and electrons. To reach higher voltages, several devices were then proposed, some of which were never developed, such as the Kelvin water dropper imagined by William Thomson (Lord Kelvin) in 1867 (Thomson 1867). This device consisted of two electrically isolated reservoirs into which positively charged droplets fell in one and negatively charged droplets in the other. Later, in the 20th century, two devices made it possible to reach very high voltages, the Cockroft–Walton generator in 1930. Powered by a low alternating voltage, this generator delivers a very high, quasi-continuous voltage. Its creators, John Douglas Cockroft and Ernest Walton, were both physicists at the Cavendish Laboratory (Cockcroft and Walton 1930). At virtually the same time, Robert Van de Graaff, Karl Taylor Compton and Lester Clare Van Atta published a paper on an electrostatic generator based on the charging of a sphere by a belt carrying charges (Van de Graaff et al. 1933). Technological developments in these two ways of obtaining high voltages are described in section 11.1.2 (Chapter 11).
However, we have strayed from the subject of this chapter: the technical developments that preceded Röntgen’s decisive experiment.
2.2.2. Vacuum control
Mastery of the vacuum, however imperfect, was the second essential element in the discovery of X-rays. The existence of the vacuum is an age-old question which, from Aristotle to Descartes, remained a philosophical one. For Aristotle, the very existence of the vacuum called into question his entire coherent construction of a full, spherical and immobile universe. In particular, for Aristotle, the falling speed was inversely proportional to the density of the surrounding environment. In a vacuum, velocity becomes infinite (Aristotle 1802 [between 335-323 BCE]). This conception of the universe gave rise to the principle that “nature abhors a vacuum”. In contrast, some 2,000 years later, Galileo did not accept Aristotle’s physical doctrine as true, but subjected it to an experiment. In fact, he used a thought experiment to describe the fall of bodies in a vacuum. The first real experimental breakthrough came in 1644, when Evangelista Torricelli demonstrated atmospheric pressure. His invention of the mercury-tube barometer followed directly from this, as did his demonstration that the space above the mercury column is empty.
To take this a step further, what was missing was the tool needed to master vacuuming. It was Otto von Guericke12 who, around 1647, invented the first air pump, similar in principle to a bicycle pump with the equivalent of a non-return valve mounted upside down. He used it to empty a glass balloon in which he carried out numerous experiments (Figure 2.7). He showed that the remaining air did not accumulate like liquid at the bottom of the balloon, and that light propagates in a vacuum, but sound does not. More spectacular were his so-called Magdeburg hemispheres experiments, demonstrating the force of atmospheric pressure: with the two hemispheres next to each other and in a vacuum, four horses could not separate them. First performed in Magdeburg in 1654, the experiment was repeated many times, notably at the court of Elector Friedrich Wilhelm in 1663.
Box 2.1.R. Boyle’s first pump
The pump has a single brass cylinder approximately 14 inches long and 3 inches in internal diameter. It rests on a sturdy wooden tripod. The piston rod is a rack driven by a toothed wheel. A hole drilled in the side of the upper end of the cylinder is fitted with a G plug, which can be removed or pushed in by hand.
Operating principle: the above figures show the arrangement of parts when the pump has completed a pumping cycle. The cylinder plug G is closed, the reservoir valve L is open and closed, G is open, and the piston is raised. G is then closed, L opened again, the piston lowered and so on (according to Wilson (1849)).
This pump was improved by Robert Boyle in 1659 (actually by Robert Hooke, his assistant). It enabled him to carry out numerous experiments on the properties of air, and it was thus that he demonstrated that the volume of a gas varies as the inverse of its pressure: Boyle’s law (or Boyle–Mariotte’s law in continental Europe). This pump was particularly tricky to build, especially when it came to sealing the moving parts. It was also capricious and very expensive. Between 1660 and 1670, only six pumps were built for London, Oxford, Cambridge (Great Britain), The Hague (Netherlands) and Paris (France). Studies on the effects of high electrical voltage on rarefied air did not begin until much later. Francis Hauksbee, whom we have just encountered for his electric machines, paid tribute to R. Boyle for his invention of the air pump:
The Honourable and moſt Excellent Mr. Boyle, by great Variety of Experiments, in almoſt every part of Philoſophy, gave much Light into the Cauſes and Operations of Nature; and particularly by the Invention of that moſt Uſeful Inſtrument the Air-Pump (Preface of Hauksbee (1709)).
F. Hauksbee was not content with this tribute: he built an excellent double-piston air pump that rapidly achieved a pressure of 0.75 inches of mercury, or 26 mbar (Figure 2.8).
In fact, the authorship of R. Boyle’s improvements was disputed, notably by a certain George Wilson, who published a history of air pumps in England:
[…] I have had occasion to study with some attention, the treatises in which he13
