Nuclear emulsion
A nuclear emulsion plate is a type of
. After exposing and developing the emulsion, single particle tracks can be observed and measured using a microscope.Description
The nuclear emulsion plate is a modified form of
It has the primary advantage of extremely high spatial precision and resolution, limited only by the size of the
The chief disadvantage of nuclear emulsion is that it is a dense and complex material (
These disadvantages, coupled with the emergence of new
For a comprehensive and technically detailed account of the subject refer to the books by Barkas[3] and by Powell, Fowler and Perkins.[2] For an extensive review of the history and wider scientific context of the nuclear emulsion method, refer to the book by Galison.[8]
History
Following the 1896 discovery of
Kinoshita included in his objectives “to see whether a single 𝛂-particle produced a detectable photographic event”. His method was to expose the emulsion to radiation from a well measured radioactive source, for which the emission rate of 𝛂-particles was known. He used that knowledge and the relative proximity of the plate to the source, to compute the number of 𝛂-particles expected to traverse the plate. He compared that number with the number of developed halide grains he counted in the emulsion, taking careful account of 'background radiation' that produced additional 'non-alpha' grains in the exposure. He completed this research project in 1909,[12] showing that it was possible “by preparing an emulsion film of very fine silver halide grains, and by using a microscope of high magnification, that the photographic method can be applied for counting 𝛂-particles with considerable accuracy”.[13] This was the first time that the observation of individual charged particles by means of a photographic emulsion had been achieved.[1] However, that was the detection of individual particle impacts, not the observation of a particle's extended trajectory. Soon after that, in 1911, Max Reinganum[14] showed that the passage of an 𝛂-particle at glancing incidence through a photographic emulsion produced, when the emulsion was developed, a row of silver halide grains outlining the trajectory of the 𝛂-particle; the first recorded observation of an extended particle track in an emulsion.[15][1]
The next steps would naturally have been to apply this technique to the detection and research of other particle types, including the
In particular Marietta Blau, working at the Institute for Radium Research, Vienna in Austria, began in 1923 to investigate alternative types of photographic emulsion plates for detection of protons, known as “H-rays” at that time.
She used a radioactive source of 𝛂-particles to irradiate paraffin wax, which has a high content of hydrogen. An 𝛂-particle may collide with a hydrogen nucleus (proton), knocking that proton out of the wax and into the photographic emulsion, where it produces a visible track of silver halide grains. After many trials, using different plates and careful shielding of the emulsion from unwanted radiation, she succeeded in making the first ever observation of proton tracks in a nuclear emulsion.[17]
By an ingenious example of lateral thinking, she applied a similar method to make the first ever observation of the impact of neutrons in nuclear emulsion. Being electrically neutral the neutron cannot, of course, be directly detected in a photographic emulsion, but if it strikes a proton in the emulsion, that recoiling proton can be detected.[18] She used this method to determine the energy spectrum of neutrons resulting from specific nuclear reaction processes. She developed a method to determine proton energies by measuring the exposed grain density along their tracks (fast minimum ionising particles interact with fewer grains than slow particles). To record the long tracks of fast protons more accurately, she enlisted British film manufacturer Ilford (now Ilford Photo) to thicken the emulsion on its commercial plates, and she experimented with other emulsion parameters — grain size, latent image retention, development conditions — to improve the visibility of alpha-particle and fast-proton tracks.[19]
In 1937,
In 1938 the German physicist
that in 1937 the two Viennese physicists, Blau and Wambacher, had exposed photographic emulsions in the Austrian Alps and had seen the tracks of low energy protons as well as 'stars' or nuclear disintegrations caused by cosmic rays.This intrigued Powell, who convinced Heitler to travel to Switzerland with a batch of llford half-tone emulsions[24] and expose them on the Jungfraujoch at 3,500 m. In a letter to 'Nature' in August 1939, they were able to confirm the observations of Blau and Wambacher.[25][26][27]
Although war brought a decisive halt to cosmic ray research in Europe between 1939 and 1945, in India
Following on from those developments, after
They subsequently used these emulsions to make two of the most significant discoveries in physics of the 20th century. First, in 1947
Second, two years later In 1949, analysing plates exposed at the
The emergence of new particle detector and particle accelerator technologies, coupled with the disadvantages noted in the introduction, led to a decline in use of Nuclear Emulsion plates in Particle Physics towards the end of the 20th century.[1] However there remained a continuing use of the method in the study of rare interactions and decay processes.[34][35][36][37][38]
More recently, searches for "
Other applications
There exist a number of scientific and technical fields where the ability of nuclear emulsion to accurately record the position, direction and energy of electrically charged particles, or to integrate their effect, has found application. These applications in most cases involve the tracing of implanted
- Biological research
- Reactive surface chemistry
- Muography) [41]
References
- ^ a b c d e f g h Herz, A.J.; Lock, W.O. (May 1966). "Nuclear Emulsions". CERN Courier. 6: 83–87. https://cds.cern.ch/record/1728791/files/vol6-issue5-p083-e.pdf
- ^ a b The Study of Elementary Particles by the Photographic Method, C.F.Powell, P.H.Fowler, D.H.Perkins: Pergamon Press, New York, 1959.
- ^ a b c Walter H. Barkas, Nuclear Research Emulsions I. Techniques and Theory, in Pure and Applied Physics: A Series of Monographs and Textbooks, Vol. 15, Academic Press, New York and London, 1963. http://becquerel.jinr.ru/text/books/Barkas_NUCL_RES_EMULSIONS.pdf
- ^ S2CID 4152828.)
{{cite journal}}
: CS1 maint: multiple names: authors list (link - ^ G. P. S. Occhialini, C. F. Powell, Nuclear Disintegrations Produced by Slow Charged Particles of Small Mass, Nature 159, 186–190 & 160, 453–456, 1947
- ^ a b R.Brown et al. Observations with Electron-Sensitive Plates Exposed to Cosmic Radiation Part 2: Further evidence for the existence of unstable charged particles, of mass ~1,000 me, and observations on their mode of decay Nature 163, 82–87 (1949). https://doi.org/10.1038/163082a0
- ^ a b Kunihiro Morishima (2015), Latest Developments in Nuclear Emulsion Technology, Physics Procedia, Volume 80, 2015, Pages 19-24, ISSN 1875-3892, https://doi.org/10.1016/j.phpro.2015.11.082.
- ^ a b Galison, Peter (1997). Image and logic: a material culture of microphysics. Chapter 3, Nuclear Emulsions: The Anxiety of the Experimenter. Chicago, Illinois: University of Chicago Press. ISBN 9780226279176.
- ^ Henri Becquerel (1896). "Sur les radiations émises par phosphorescence". Comptes Rendus. 122: 420–421.
- ^ a b E. Rutherford, Philosophical Magazine, July 1905, January 1906 and April 1906
- ^ His name is written here in accepted Japanese form: surname followed by given name, rather than following Western convention.
- ^ Rutherford communicated Kinoshita's paper to the Royal Society in November 1909
- ^ Kinoshita, S. (1910). "The Photographic Action of the 𝛂-Particles emitted from Radioactive Substances". Proc. R. Soc. 83A: 432–458.
- ^ Maximilian Reinganum (1876-1914) was Professor of Physics at the University of Freiburg im Breisgau in 1911. He is referenced in "The Collected Papers of Albert Einstein, Volume 1: The Early Years, 1879-1902", p305. Princeton University Press (1987) ISBN 0-691-08407-6. Edited by John Stachel, David C. Cassidy, and Robert Schulmann. In a letter to Mileva Marić, Einstein discusses a paper by Reinganum. The following note is added by the editors: Maximilian Reinganum (1876-1914) was not Dutch, but the article in Annalen der Physik [*] on the electron theory of metals is datelined “Leiden Mia 1900”. By use of the equipartition theorem, Reinganum derived an expression for the ratio between thermal and electrical conductivity, which was equivalent to that given by Paul Drude, but which could be evaluated more precisely. Reinganum’s result was in good agreement with experiment. [*] Max Reinganum (1900): "Theoretical determination of the ratio of heat and electricity conduction of metals from Drude's electron theory", Annalen der Physik Volume 307 Issue 6 Pages 398-403. https://doi.org/10.1002/andp.19003070613
- ^ Reinganum, M. ‘Streuung und photographische Wirkung der 𝛂-Strahlen’ Phys. Z., vol. 12, p 1076 (1911)
- ^ A doubly ionised Helium ion
- ^ Marietta Blau, The photographic effect of natural H-rays, (in German), Sitzungsberichte Akademie der Wissenschaften in Wien, IIa 134: 427 (1925). English translation (http://cwp.library.ucla.edu/articles/blau/blau-rosenz.html)
- ^ Marietta Blau and Hertha Wambacher, Photographic detection of protons liberated by neutrons. II, Sitzungsberichte Akademie der Wissenschaften in Wien, 141: 617 (1932).
- ^ Ruth Lewin Sime, Marietta Blau in the history of cosmic rays, Physics Today, Volume 65, Issue 10, p.8, October 2012
- ^ Marietta Blau and Hertha Wambacher: Disintegration Processes by Cosmic Rays with the Simultaneous Emission of Several Heavy Particles, Nature 140: 585 (1937).
- ISBN 3-205-77088-9(in German)
- ^ Sime, R.L. Marietta Blau: Pioneer of Photographic Nuclear Emulsion and Particle Physics. Phys. Perspect. 15, 3-32 (2013). https://doi.org/10.1007/s00016-012-0097-6
- C.T.R. Wilson, who won the Nobel Prize for Physics in 1927 for his invention of the cloud chamber, had been Powell's Ph.D. supervisor at Cambridge.
- ^ These emulsions were clearly not standard Ilford photographic plates. In their published paper Heitler et al. state "A set of Ilford half-tone plates (emulsion 70 microns thick and sensitive to 𝛂-particles and protons)", which is almost certainly the type produced to Blau's 1937 research specifications.
- ^ W. HEITLER, C. F. POWELL & G. E. F. FERTEL, Heavy Cosmic Ray Particles at Jungfraujoch and Sea-Level, Nature volume 144, pages 283–284 (1939)
- ^ Owen Lock ‘’Half a century ago - The pion pioneers’’ CERN Courier vol. 37 no. 5 June 1997 pp 2-6.
- ^ Curiously, although Galison notes that "Dispatched to expose plates [at the Jungfrau], one of Powell’s colleagues returned on 20 December 1938" he does not name that colleague as Heitler and makes no reference to the joint paper which was Powell's first using the Nuclear emulsion method.
- ^ BOSE, D., CHOWDHRY, B. Photographic Plates as Detectors of Mesotron Showers. Nature 145, 894–895 (1940). https://doi.org/10.1038/145894a0
- ^ D. M. Bose and B. Chowdhury, Origin and nature of heavy ionization particles detected on photographic plates exposed to cosmic rays, Nature 147(1941):240-241. D M, Bose and B. Chowdhury, A photographic method of estimating the mass of mesotron, Nature 148(1941): 259-260. D M, Bose and B. Chowdhury, A photographic method of estimating the mass of mesotron, Nature 149 (1942): 302.
- ^ S C Roy and Rajinder Singh (2016), D M Bose and Cosmic Ray Research, Science and Culture, November-December, Vol. 82, Nos. 11–12 pp 364-377.
- ^ Rajinder Singh, Suprakash C. Roy (2018),
A Jewel Unearthed: Bibha Chowdhuri - The Story of an Indian Women Scientist, Shaker Verlag Aachen ISBN 978-3-8440-6126-0.
- ^ Suzie Sheehy (2022), The Matter of Everything : A history of Discovery. Bloomsbury Publishing.
- ^ C.M.G. Lattes, R.H.Fowler, and R.Cuer, "Range-Energy Relation for Protons and a-Particles in the New Ilford 'Nuclear Research' Emulsions", Nature 159 (1947), 301-2
- ^ Nuclear Emulsion Evidence for Parity Nonconservation in the Decay Chain π + → μ + → e + π + →μ + →e + , J.I. Friedman(Chicago U., EFI), V.L. Telegdi(Chicago U., EFI) (Jun, 1957) Published in: Phys.Rev. 106 (1957) 1290-1293
- ^ A measurement of the magnetic moment of the Λ 0 hyperon, G. Charrière, M. Gailloud, Ph. Rosselet(Lausanne U), R. Weill, W.M. Gibson(Bristol U) et al. (1965) Published in: Phys.Lett. 15 (1965) 66-69
- .
- ^ Nuclear Interactions of Superhigh-energy Cosmic Rays Observed by Mountain Emulsion Chambers, Pamir and Mt. Fuji and Chacaltaya Collaborations•S.G. Baiburina(Lebedev Inst.) et al. (Feb, 1981) Published in: Nucl.Phys.B 191 (1981) 1-25
- ^ Particle production in interactions of 200-GeV/nucleon oxygen and sulfur nuclei in nuclear emulsion, KLM Collaboration•A. Dabrowska(Cracow, INP) et al. (1992) Published in: Phys.Rev.D 47 (1993) 1751-1761
- S2CID 119256958.
- S2CID 119101090.
- ^ Andrea Giammanco, Université de Louvain; Cosmic rays for Cultural Heritage, CERN Courier Volume 63 Number 3 May/June 2023, pp 32-35, FEATURE: Muography.
- ^ Morishima, K., Kuno, M., Nishio, A. et al. Discovery of a big void in Khufu’s Pyramid by observation of cosmic-ray muons. Nature 552, 386–390 (2017). https://doi.org/10.1038/nature24647
See also Scanpyramids