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Volume 47, Number 5, September/October 2010

Harrie Massey Medal for 2010 awarded to Hans Bachor Alan Walsh Medal for 2010 – Commercialising Laboratory Lasers Walter Boas Medal for 2010 – Plasma Nanoscience Bonsai Black Hole in Our Backyard AustPhys_475 20/04/11 11:45 PM Page OFCii AustPhys_475 20/04/11 11:45 PM Page 97

       

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A Publication of the Australian Institute of Promoting the role of physics in research, education, industry and the community.

Editor Peter Robertson [email protected] Editorial Walter Boas Medal for 2010 100 Introducing the new editor of Australian 114 Ken Ostrikov describes how plasma Assistant Editor nanoscience is able to control complex Dr Akin Budi Physics organisations of atomic matter at sub- [email protected] President’s Column nanometre to microscopic scales Book Reviews Editor 101 Incoming AIP President, Marc Duldig, Dr John Macfarlane discusses the importance to our How Much Free Will Do We Have? [email protected] profession of ‘scientific volunteerism’ 119 The work of the ANU’s Michael Hall on the Bell inequalities is previewed by Tim Samplings Editor News & Comment Wetherall Don Price 102 Tanya Monro named South Australian of [email protected] the Year for 2011 Book Reviews 121 John Macfarlane on ‘The Cold Wars: A Editorial Board CERN Director-General announces new History of Superconductivity’ by Jean A/Prof Brian James (Chair) Australian centre Matricon and Georges Waysand Dr M. A. Box Australian Synchrotron restructures with Lee Weissel on ‘The Quantum Frontier: Dr J. Holdsworth several senior appointments The Large Hadron Collider’ by Don A/Prof R. J. Stening Lincoln Prof H. A. Bachor Harrie Massey Medal for 2010 Prof H. Rubinsztein-Dunlop 105 Ben Villani profiles the research of ANU Obituary Prof S. Tingay Hans Bachor 122 Marshall Stoneham 1940–2011 Associate Editor – Education Alan Walsh Medal for 2010 Product News Dr Colin Taylor [email protected] 106 Robert Scholten describes his fascinating 124 A review of new products from Lastek, journey of how a laboratory laser led to Associate Editors Coherent Scientific and Warsash the foundation of a company that Dr John Humble [email protected] Scientific Dr Chris Lund [email protected] exports to labs all over the world Dr Laurence Campbell Inside Back Cover A Bonsai Black Hole [email protected] Physics conferences ahead for 2011 and 2012 111 Robert Soria explains how the discovery Dr Frederick Osman [email protected] of powerful jets from a nearby black hole Peter Robertson [email protected] reveals new clues about the behaviour of Dr Patrick Keleher [email protected] massive quasars in the early universe Submission Guidelines Articles for submission to Australian Physics should be sent in electronicaly. Word or rich text format are preferred. Images should not be embedded in the document, but should be sent as high resolution attachments in eps, tiff or jpg format. Authors Cover should also send a short bio and a recent photo. The Editor reserves the right to edit articles based on A composite multi-band image of Pictor A, a space requirements and editorial content. close and powerful Fanaroff–Riley class II Contributions should be sent to the Editor. radio source. The host appears as a non-de- Advertising script point at the centre of the background Enquiries should be sent to the Editor. optical image (European Southern Observa- tory DSS-2 R-band image in grey). An X-ray Published six times a year. Copyright 2010 jet is seen emanating from the centre of the Pub. No. PP 224960 / 00008 galaxy extending across 360,000 light-years ISSN 1837-5375 toward a brilliant hotspot (Chandra X-ray image in blue). Two nearly circular lobes, The statements made and the opinions expressed in normally reminiscent of a ‘dying’ radio Australian Physics do not necessarily reflect the views of the Australian or its Council source, are seen at radio wavelengths (6 cm or Committees. Australia Telescope Compact Array image in red), but the presence of hot spots seen at the Production lobe extremities suggests that the jet may have been recently re-activated. A similar object Control Publications Pty Ltd known as Fornax A is featured in Robert Soria’s article on p. 111. [Courtesy: Emil Lenc, Box 2155 Wattletree Rd PO, VIC 3145. [email protected] Australia Telescope National Facility, Sydney]

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Australian Institute of Physics AIP website: www.aip.org.au Editorial AIP Executive Challenges President Dr Marc Duldig [email protected] Vice President Dr Robert Robinson Ahead [email protected] Secretary Dr Andrew Greentree It is an honour to be asked to be the next [email protected] editor of Australian Physics, a magazine I’ve Treasurer Dr Judith Pollard judith.pollard@.edu.au been reading for over thirty years. Some of Registrar A/Prof Bob Loss you may remember me as the editor of the [email protected] Australian Journal of Physics, formerly pub- Immediate Past President A/Prof Brian James lished by CSIRO and the Australian Acad- [email protected] emy of Science. During my time as editor Special Projects Officers (1980 to 2001), I looked on Australian Dr John Humble [email protected] Physics as the ‘sister’ to Aust. J. Phys. and Dr Olivia Samardzic there was always a close relationship be- [email protected] tween the two publications. Publishing a magazine though is quite AIP ACT Branch different to a research journal and so I’ll be Chair Dr Anna Wilson on a steep learning curve over the next few (Ken) Ostrikov (CSIRO) for his work on [email protected] months. As you know, the magazine is plasma nanoscience. Secretary Joe Hope [email protected] running over six months late and so the We also have a profile on Hans Bachor major challenge will be to get the publica- (Australian National University) who was AIP NSW Branch tion schedule back on track. This can only awarded the Harrie Massey Medal by the Chair Dr Graeme Melville [email protected] happen if we have a stream of quality ma- AIP and the UK IOP for his research in Secretary Dr Frederick Osman terial coming our way. So I strongly en- quantum optics. An article by Hans de- [email protected] courage you to think about preparing a scribing the development of quantum op- feature article on your research or any other tics in Australia will appear in our next AIP QLD Branch Chair Dr Joel Corney area of physics that interests you. If you issue. Similarly, we plan to publish an arti- [email protected] have an idea for an article, contact me and cle by Joe Wolfe (University of NSW) who Secretary Dr Till Weinhold we can discuss how to develop the idea. was awarded the AIP Education Medal [email protected] At the highly successful Congress in during the Congress. Melbourne last December the AIP awarded Lastly, I can mention that we have AIP SA Branch a number of prizes and medals. In this formed a very talented editorial team and Chair Dr Scott Foster [email protected] issue we bring you two articles based on over the next few issues I will be introduc- Secretary Dr Laurence Campbell these presentations: the award of the Sir ing them to you. The team will be working [email protected] Alan Walsh Medal to Robert Scholten hard this year to help get Australian Physics () for his commer- back on schedule. AIP TAS Branch cialisation of a laboratory laser and the Chair Dr Elizabeth Chelkowska award of the Walter Boas Medal to Kostya Peter Robertson [email protected] Secretary Dr Stephen Newbury [email protected]

AIP VIC Branch Letter So the publicised estimates in microsieverts Chair Dr Andrew Stevenson or millisieverts left me in the dark. I suggest [email protected] an authoritative discussion by an expert in Secretary Dr Mark Boland Dear Editor, the field around the units of exposed dose [email protected] The wide publicity given to possible nuclear (Grays) and absorbed dose (Sieverts), rela- AIP WA Branch radiation levels arising from the recent re- tive to the current recommended maxi- Chair A/Prof Marjan Zadnik actor disaster in Japan has prompted me to mum levels, might form a suitable subject [email protected] revise my knowledge of the units currently for a future article in Australian Physics. Secretary Dr Andrea Biondo in use. I grew up with, and became familiar [email protected] with, the rad and the rem, but have not Sincerely, caught up with the Gray and the Sievert. John Macfarlane Printing Pinnacle Print Group 288 Dundas Street, Thornbury VIC 3071 www.pinnacleprintgroup.com.au

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President’s column Scientific Volunteerism While thinking about what I should write assessment and promotion considerations. for my first President’s column I became However, there is another aspect to sci- very aware of the honour of being elected, entific volunteerism that I also see as of and slightly daunted by the role I have high importance and that appears to be taken on. I see the Presidency as a welcome under even greater stress than the peer re- challenge to try and have an impact. There view system – the role of representation on is much that is great about our Institute, scientific societies. It is becoming more and but there are also many improvements that more difficult to fill branch, group and na- can be made, and I intend to work with the tional positions in the Institute, and it is rest of the executive to put some of the nec- not entirely clear why this situation has de- essary improvements into place. veloped. You will see we now have a new editor, In the past such representation was a and a plan to catch up on the publication valuable addition to one’s CV, and I would of the magazine so that the cover date and hope that this is still the case. Because one the publication date are once again aligned. of the most valuable ways for any person to This relies on you as members to provide advance their career is through the profes- articles that highlight the range and excel- sional networks they develop. These are tirely. I think that such service, in appro- lence of physics carried out across Australia gateways to opportunity, because with net- priate amounts relative to the stage of their and to tell your fellow about it. working comes information. Information career, is invaluable and I ask all leaders to We will only catch up if we have a steady about new developments, jobs, committees promote rather than discourage involve- supply of articles so please let’s hear about that will influence the direction your cho- ment for the reasons I have mentioned your exciting work. sen field takes that could eventually benefit above and to recognise these contributions This actually forms a nice introduction you through enhancement of your field. positively when assessing staff. to the main theme of my first President’s The people you get to know through Finally, I still believe that all of us who column which is the role and importance volunteer committees in societies are one of have made a career out of our chosen sci- of volunteerism to science and its societies. the richest sources of networking you will entific field have a responsibility to put Cathy Foley, in a previous President’s col- find. They are invariably from a far wider something back into a system that has umn some years ago, discussed volunteer- range of areas than your direct experience, looked after us. This is particularly true for ing from the perspective of it forming one they will include the movers and shakers of mid and late career people who should be of the underlying structures that support tomorrow and they will expose you to ways able to find some time for just such activi- the scientific method. The role of peer re- of thinking and political awareness that will ties. view – be it for journal articles, project or always serve you well. There are few better I would welcome comment, criticism funding proposals, fellowships and promo- enhancements to your professional skill set and discussion on this column and hope tions – is part of the scientific process and than your networks. that members will send a ‘Letter to the Ed- its success. Without voluntary refereeing I have heard it said that some supervi- itor’ for inclusion in the next issue. Feel the whole system would simply fail. As sors, managers or department heads have free to send in letters on other topics as well such, it is important that we all play our opposed junior staff ‘wasting their valuable because it is good to have open discourse part in the process and equally that as su- time’ on society committees when they through these pages. pervisors or managers of staff we also recog- should be concentrating on their teaching nise this contribution in performance or research. I disagree with that view en- Marc Duldig

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News & Comment

Professor Tanya Monro () is South Australian of the Year for 2011.

Tanya Monro named South of South Australia, Kevin Scarce, at a cere- sity of Southampton in the UK. Australian of the Year for 2011 mony last November. In 2006 Tanya was named as one of the Physicist Tanya Monro has been named Tanya became the inaugural professor in top 10 brightest young minds in Australia South Australia’s ‘Australian of the Year’ for photonics at the University of Adelaide in by science magazine Cosmos. In 2008 she 2011. Tanya, who is the Director of the In- 2005. Her PhD research focused on devel- was awarded the Prime Minister’s Prize for stitute for Photonics and Advanced Sensing oping new classes of optical fibres, for Physical Scientist of the Year. She is cur- (IPAS) within the School of & which she received the Bragg Gold Medal rently an ARC Federation Fellow. Physics at the University of Adelaide, was for the best physics PhD in Australia. From Tanya has been recognised for her work presented with her award by the Governor 1998 to 2004 Tanya worked at the Univer- in the field of photonics – technology that

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allows the generation and control of light using glass optical fibres. This enables the creation of new tools for scientific research and solutions for problems in areas such as information processing, surgery, health monitoring, military technology, agricul- ture and environmental monitoring. She has published over 300 papers in journals and refereed conference proceedings. The vision of the Institute for Photonics and Advanced Sensing is to bring together researchers in physics, chemistry and biol- ogy to pursue a trans-disciplinary approach to science for applications in defence, pre- ventative health, environmental monitor- ing and food and wine. In late 2008, IPAS was awarded $29 million from the federal government’s HEEF (EIF) scheme towards the construction of a new building for IPAS on the North Terrace campus of the Uni- versity of Adelaide. This project is also re- ceiving support from the South Australian state government and the Defence Science & Technology Organisation. As winner of the SA ‘Australian of the Year’ award, Tanya joined recipients from other States and Territories as a finalist in Minister Kim Carr during an official visit to CERN in March this year, with Director-General the national awards which were announced Rolf-Dieter Heuer (centre) and Professor Geoff Taylor (University of Melbourne) [credit: CERN]. in Canberra on Australia Day on 26 Janu- ary 2011. space, microscopic black holes, and an ex- fessor Heuer in the ARC Centre has rein- CERN Director-General tension of relativity called supersymmetry, forced the international standing of the announces New Australian Centre are possible discoveries motivated by plau- expertise in Australia. Ac- The Director-General of CERN in Switzer- sible extensions of the standard model of cording to Taylor: “We are very excited to land, Professor Rolf-Dieter Heuer, an- particle physics.” announce the start of a new era of Aus- nounced a new $25 million Australian More particularly, CERN physicists are tralian collaborative scientific research in Research Council Centre to explore the ori- desperately hoping to discover the elusive the field of particle physics and understand- gins of the universe during the Australian Higgs boson, predicted in 1964 by UK’s ing the beginnings of the universe”. Institute of Physics Congress last Decem- Peter Higgs and others, which explains how ber. Heuer was also appointed as the chair particles of matter achieve the property we Australian Synchrotron announces Senior Appointments of the International Advisory Committee know as mass. of the ARC Centre. As Geoff Taylor notes: “The Centre will The Australian Synchrotron (AS) has an- Led by the University of Melbourne, the greatly expand Australia’s role in the largest nounced a number of new senior appoint- ARC Centre of Excellence for Experimen- pure science enterprise on the planet, the ments, as well as a major re-organisation of tal Particle Physics at the Terascale will ex- LHC. Our collective scientific effort will responsibilities for senior staff. plore particle physics at terascale energies leave a legacy of enhanced national capabil- Professor Keith Nugent will be the new through the ATLAS experiment, a giant ity at the forefront of this intellectual en- Director of the Australian Synchrotron, a particle detector which is an essential part deavour.” part-time position. He replaces Dr George of the Large Hadron Collider (LHC) at The Centre brings together scientists Borg who was appointed Acting Director CERN. from the University of Melbourne, the after the controversial departure of the in- Director of the ARC Centre, Professor University of Adelaide, Monash University, augural director, Professor Robert Lamb, in Geoff Taylor at Melbourne’s School of the and international 2009. Physics said that by probing fundamental collaborators including Cambridge Univer- Currently, Nugent is Research Director particle interactions at higher energies, sity, the University of Pennsylvania, of the ARC Centre of Excellence for Co- more would be discovered about the early Freiburg University, the University of herent X-ray Science and Laureate Profes- stages of the evolution of the universe after Geneva, Duke University and INFN Mi- sor of Physics at the University of the Big Bang: “Exciting new physics such lano. Melbourne. He will combine the position as the existence of extra dimensions of The involvement of CERN director Pro- with his existing responsibilities. The ap-

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New appointments at the Australian Synchrotron: part-time Director, Professor Keith Nugent (left) and Head of Science, Professor Andrew Peele.

pointment follows an extensive international search. According to Peele, by synchrotron standards the science facility Nugent will focus on and be responsible for scientific leadership was still very young and its credentials and performance, first class. and strategic development. He is currently a member of the AS “In its short life, the Australian Synchrotron has attracted some of Board of Directors, but will step down from the Board to take on the best minds in synchrotron science and, in addition to support- his new role. The AS Board said it was delighted to be able to ap- ing the research needs of over 2000 domestic and international sci- point a distinguished and respected scientist such as Professor Nu- entists since its opening in 2007, it continues to run its existing gent. beamlines at better than 99% per cent reliability.” A second senior appointment is Dr Andrew Peele who took up “The Australian Synchrotron has realised its aims in establishing the new position of Head of Science late in 2010. Peele who is an its first suite of beamlines covering research techniques ranging Associate Professor at La Trobe University and head of its X-ray from imaging and medical therapy to powder diffraction, but it Science Group joins the AS on full-time secondment. must grow so as to continue to provide Australian and interna- As an investigator on grants totalling more than $25 million, tional researchers with access to a world-class science and research Peele has significant experience in team management and science facility”, Peele said. administration, having previously been the chair of the AIP Vic- The Board said the re-organisation aimed to further enhance torian Branch and co-chair of the organising committee of the AIP the Australian Synchrotron focus on producing great science, while Congress last December. He also has extensive experience in syn- ensuring that its administration maintained high standards of ef- chrotron science having published over 80 refereed articles. fectiveness, accountability and compliance.

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Harrie Massey Medal for 2010 awarded to Hans Bachor

Ben Villani

How do you pop a small purple balloon awarded the Harrie Massey Medal of the that is blown up inside a large clear bal- Australian Institute of Physics (AIP) and “Our aim is to test loon? With a green laser of course! The en- the UK Institute of Physics (IOP) and the what is possible! ergy in green light passes through clear Beattie Steel Medal of the Australian Opti- rubber and is then absorbed by the purple cal Society. These were presented to him For 25 years we balloon – which heats up and bursts. during the AIP Congress held in Mel- Professor Hans Bachor used this surpris- bourne. Together with the AIP Award for have been ing phenomenon to show how lasers can be Outstanding Services to Physics in 2009, scrutinising many used in eye surgery. The demonstration was the decorations represent a rare ‘trifecta’ of one of many he performed at an event held recognition which very few scientists have of the untested last November at Questacon – the National received. Bachor began studying predictions of lasers and plasma physics dur- quantum ing his PhD in Germany. In 1981 he came to Australia mechanics.” looking for adventure and per- formed post-doctoral work at internationally. He has guided and super- the ANU. Here he enjoyed the vised 28 PhD graduates, and says “They freedom to study something have all worked very hard and found their novel and he initiated quan- way as professionals. I’m proud about the tum optics experiments in Aus- fact that I have helped them with one im- tralia. Currently, Bachor is portant step.” Director of the internationally At the same time Bachor acknowledges recognised ARC Centre of he could not have achieved success by Excellence for Quantum-Atom working alone. “You can’t do physics all by Optics (ACQAO). He and his yourself. I’ve been very fortunate over the team are researching the years to work with many teams. And while strange behaviour of light and I’ve played in these teams, I’ve got into the matter on the quantum scale. sin bin occasionally, but I’ve also won some They do this by designing ex- premierships. I became a trainer, a coach periments that manipulate and now a mentor. That’s how you only a very small number of progress. I’ve always enjoyed the fact, that atoms or photons. really, doing science is very much a team ac- Professor Hans Bachor at the ANU’s ARC Centre of “Our aim is to test what is tivity.” Excellence for Quantum-Atom Optics [courtesy: Damien possible! For 25 years we have And today, as director of ACQAO, Ba- Hughes]. been scrutinising many of the chor compares his job to that of an orches- untested predictions of quan- tra conductor. He says it’s like working with Science and Technology Centre to mark the tum mechanics.” Bachor’s extensive re- amazing and creative solo artists, but the 50th anniversary of the laser’s invention. search contribution has been published in most incredible sounds happen when The performance is an excellent example of over 150 journal articles. The work con- everyone plays together. “Working together Bachor’s efforts to engage the public with ducted with ACQAO and others will have is an essential feature in science because physics. many practical applications and has the po- everybody contributes something different. He has recently received awards for his tential to revolutionise communications, Everybody thinks slightly different – theo- contributions to scientific outreach as well computing, cryptography and ultra precise retically, mathematically, or like an engineer as his outstanding achievements in re- measurements of time, space and gravity. – and all of these styles are necessary.” search, teaching and mentoring of students, As well as scientific research and public all done at the Australian National Univer- engagement, Bachor is known for his pas- Ben Villani moved recently from sity (ANU). sionate commitment to teaching and the Questacon to the ANU where he is a In December 2010 Hans Bachor was inspiring lectures delivered at the ANU and science communicator.

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Alan Walsh Medal From Lab to MOGLabs: Commercialising Laboratory Lasers

Robert E. Scholten

The interactions between atoms and coherent lightfields have enabled a vast assortment of fascinating research advances and technological applications, including laser cooling of atoms, Bose -Einstein condensation, magnetic imaging of hyper-polarised gas, and quantum squeezing. Experiments in these areas rely on tuneable narrow linewidth lasers, particularly external cavity diode lasers. While today we can choose from several good commercially available lasers, it was not long ago that researchers had little choice but to build their own. This is the story of how a rat-nest tangle of wires in a university laboratory became the foundation of a company that exports to labs all over the world.

Sir Alan Walsh with a UK scientific instrument maker, Everyone has seen the yellow glow of Walsh helped some local electronics, glass sodium when salt is thrown in a fire, and blowing and machining companies put to- for anyone with even a primary school con- gether do-it-yourself AAS kits, and they cept of atomic structure, it is not too hard eventually became Varian Australia, with a to imagine identifying material constituents staff of 400 and a similar number at exter- from emission spectra. Until the early nal contractors. 1950s, emission was the basis of spectro- graphic atomic analysis, until Sir Alan Tuneable lasers Walsh invented and developed the atomic The story of MOGLabs, named after the absorption spectrometer, which revolu- Fig. 1. Sir Alan Walsh with an early atomic Melbourne Optics Group, is also based on tionised chemical analysis in the 1950s absorption spectrometer [courtesy: the interactions of light with atoms, in this through three key contributions [1]. Science Image, CSIRO]. case the need for better lasers to do experi- The first was his understanding that even ments in atom optics. The development of in a flame or discharge, only a small frac- of the spectrum not absorbed by atomic tuneable lasers in the 1970s and 80s en- tion of constituent atoms will be excited constituents of interest. abled an explosion of new science, includ- and therefore emit, whereas the much The atomic absorption spectrometer ing laser cooling of atoms to micro- and larger ground state fraction will readily ab- (AAS) provides fast, simple, accurate and nano-Kelvin temperatures, Bose-Einstein sorb resonant radiation. Absorption was highly sensitive measurements of atomic condensation, quantum optical squeezing, commonly used for molecular analysis but constituents, with applications in medicine, atomic clocks, exquisite gravity gradiome- the flames and discharges necessary to agriculture, mineral exploration, metal- ters, the GPS system, new tests of the atomise a sample inherently produced lurgy, food analysis, biochemistry, environ- equivalence principle, and slow light, with strong emission which swamped the ab- mental monitoring, and probably many new examples arising almost daily. Many sorption measurements. Walsh realised that more. In 1968 the AAS was described by rely on lasers that can be tuned precisely to the two could be separated by modulating Sir Ian Wark, Chief of the CSIRO Division an atomic transition, with optical frequen- the light source which was being absorbed of Industrial Chemistry, as “the most sig- cies of order 1015 Hz and linewidths of 105 combined with synchronous detection; that nificant advance in chemical analysis this Hz or better: an uncertainty better than is, with a lock-in amplifier. Finally, he used century” [1]. one part in 1010. spectral line lamps, rather than a broad The invention and development of the As an example, my lab has developed a continuous spectrum white light source. AAS occurred just as a booming global source of ultracold electrons, based on pho- Much higher signal-to-noise ratios were mining industry needed accurate and reli- toionisation of laser cooled atoms, for appli- possible since no light was wasted in areas able chemical analysis. After a slow start cations in diffractive imaging at the

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nanoscale. Fig. 2 shows a schematic of the ex- periment. Rubidium atoms effuse from a thermal reservoir at speeds of 300 m/s. They are slowed by counter-propagating laser beams, and cooled and trapped by additional lasers in a magneto-optic trap. A cloud of 108 atoms is then excited (by a laser) and those excited atoms are ionised (by a laser) to pro- duce a cold plasma. The electrons (or ions) are extracted with an electrostatic field to pro- duce a highly coherent beam of electron bunches (see Fig. 3). Semiconductor lasers have made mod- Fig. 2. Atoms are cooled and trapped using narrow linewidth tuneable diode lasers, and ern laser cooling experiments feasible. They then photoionised to produce a very cold electron bunch. are tuneable, narrow in linewidth, compact, and reliable. But in the early days, commer- cial products were expensive and most labs found they could do just as well by making their own. My lab developed a popular de- sign [2], and also designed and built some crude electronics to drive the lasers (see Fig. 4). The electronics were functional, but frustrating. A rat-nest of wires was time consuming to build, a nightmare to debug, and underwhelming in performance. Two pivotal opportunities Two critical events occurred at almost the same time. The first was my sabbatical in Fig. 3. Electron bunches can be arbitrarily shaped by exciting and photoionising only 2002 at the Technical University of Eind- some of the cold atoms, for example in the letters CXS. Because the electrons are very hoven (TU/e), in The Netherlands. Some cold, the pattern is retained when the electron bunch propagates. of my students accompanied me, including Lincoln Turner. Our colleagues at TU/e work, our understanding grew beyond sim- lasers. Alex was accustomed to designing also had problems with their laser electron- ple PID concepts. incredibly complex circuit boards for cut- ics, and so Lincoln and some Dutch PhD We were then fortunate in being able to ting-edge technology in fibre communica- students decided they needed to under- employ an outstanding electronics engi- tions, so it was like hitting a nail with a stand electronic control theory. The books neer, Alex Slavec, at The University of Mel- jackhammer. The rat-nest of wires became were large and obtuse, but fortunately their bourne, just when we thought we knew an elegant six-layer circuit board with al- brains were even larger, and through their what electronics was needed to drive our most 1000 surface-mount components,

Fig. 4. Lab-built electronics: a rat-nest of wires.

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noise differential photodetector, and every- thing needed for synchronous detection, as used by Sir Alan in his atomic absorption spectrometer. That is, a sine generator to drive an external modulator, a demodulator (lock-in amplifier), and feedback servo shaping based on the control theory learned in Eindhoven. The performance is defined primarily by low noise [3]. The frequency of light from a laser diode is extremely sensitive to cur- rent, about 3 MHz/μA. To achieve the 100 kHz linewidths desired for laser cool- ing of atoms, the current noise must be lower than 30 nA, for a 200 mA DC sup- ply. The MOGbox design is steadfastly ana- logue, with no digital clock signals. The power supplies are all linear, rather than switchmode. The transformer is toroidal to minimise external AC magnetic fields through the PCB, with an additional layer of magnetic shielding to be sure. The DC voltage supplies are each filtered and regu- lated, then filtered and regulated again. Sensitive signals on the PCB are run along inner layers with Faraday shielding copper on other layers around them. The result is very nearly too small to measure: -150 dBm/√Hz, i.e. 1 attowatt/√Hz (10−18 W/√Hz), or in current terms, below 100 pA/√Hz. No other laser diode driver has demonstrated such low noise, and using a MOGbox, a laser linewidth of 35 kHz (rms) is readily achievable [4]. Corporate commercialisation There are hundreds, if not thousands, of laser cooling labs around the world, nearly Fig. 5. Iconic sculpture at the gates of the Technical University of Eindhoven in The Netherlands. all using external cavity diode lasers. ECDL products are also used in chemistry labs, en- vironmental monitoring research, astro- code-named Augustus (‘the revered one’). sold all but two of the twelve (see Fig. 7). physics (e.g. investigating guide stars based Alex simulated every stage of the design, Why? What is so good about a MOG? on alkali vapours), metrology labs, fibre before laying out the circuit board, and The answer is a combination of ergonomics communications research, and many other hand-soldering the thousand tiny surface and performance. The ergonomics is im- areas. In 2007, a US manufacturer adver- mount components to the board. And con- portant: compared to the Teutonic style tised that they had sold over 5000 ECDLs. trary to all our prior experience in design- and user-interface of the main competition, With several enthusiastic users of our first ing apparatus for physics experiments, his a MOGLabs controller (‘MOGbox’) is easy batch of controllers, we contacted the com- worked. to use, with accessible knobs and switches, mercialisation arm of our university, Mel- convenient selection of signals to monitor bourne Ventures, to discuss the possibility No returns on an oscilloscope, and most importantly, of licensing the design to an existing man- We wanted eight for the lab, but the incre- everything needed for running a laser and ufacturer. mental cost per unit was relatively small, so locking it to an atomic transition. To run Melbourne Ventures investigated possi- we built a few extra – twelve in total. We the laser, the MOGbox includes a current ble buyers, including existing manufactur- sent a few to friends for their suggestions supply for the diode, a temperature con- ers of ECDLs and other laser and feedback – but they didn’t return them. troller, frequency sweep ramp, and high manufacturers that did not yet have these To quote: “… please, please, please can we voltage outputs to control piezo-electric products. They estimated a total market of buy it?”, and eventually we (the University) transducers. For locking, it includes a low- around 700 units over five years, with an

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were paying for. We contracted a Sydney company known as Konstruktdesign to de- sign a better enclosure – money well spent, but money our business did not have. The only readily accessible finance was that tied to the family mortgages. And so our fami- lies had to take a leap of faith, a faith that faltered a little when we decided to buy the

“We don’t know how to sell this, so why don’t you?”

MOGbox components in batches of 25 to get the costs down. And faltered a little more when the time came to pay for a Fig. 6. From rat-nest to six-layer PCB and surface-mount components. batch of 25 assembled PCBs: sufficient funds to buy each of our families a new car end-user value of something like $1 million we start our own company to build and sell – instead sent by wire to a company in Sil- per annum. Contemplating the inventor’s the product. In other words: “We don’t icon Valley. share of the royalties, we started looking at know how to sell this, so why don’t you?” Fortunately, Konstruktdesign and the holiday homes in the exclusive Victorian We were a little passionate about it, fu- PCB manufacturer did a fantastic job, and beach resort of Sorrento… elled by positive comments from users. And the controllers worked well and looked the so, indeed it seemed like a good idea at the part. They have been sold to all corners of DIY commercialisation time. We registered MOG Laboratories as the globe, from South Africa to the United Meanwhile, back in the lab… actually out- a proper business (i.e. Pty Ltd), a partner- Arab Emirates, the USA to China. A single side the lab, in Alex’s home: the dot-com in- ship between myself and Alex, and signed customer now has 14. Even the strongest dustry had begun to recover and Alex a three-year licensing agreement with Mel- competitors to MOGLabs have bought moved back to the fibre communications bourne Ventures. them, and it is gratifying – and somewhat industry at the end of 2003, and continued One of the first steps was to improve the annoying – to see some familiar features in his work on the MOGbox in his own time. appearance of the MOGbox, to better re- their latest products. The company has Only one of the prototypes was finished; he flect the high quality of the electronics in- moved from home dining-room to a busi- completed the second unit, and then the side. The units worked well, but looked ness incubator, and hopes to move again to first batch of 12 units, after changing jobs. very homemade. It was clear that we larger premises soon. So far there is only Even while negotiating with Melbourne needed to increase the price if the company one part-time employee; most of the work Ventures, we continued to improve the de- was to be viable, but it was critical that cus- is contracted to over 100 suppliers from sign, and after some months they suggested tomers should appreciate the quality they Melbourne and Sydney to San Jose.

Fig. 7. One of the twelve units which were sold to other labs in Australia, the US, The Netherlands and to a notable German manufacturer of external cavity diode lasers.

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improvements to the flagship product, and even to research and develop, in house, the obvious extension – a MOGLabs external cavity diode laser. But we have many more ideas for new products, and see a promising future in following Sir Alan Walsh’s lead, in designing and manufacturing scientific instrumentation in Aus- tralia. Acknowledgements Many people, knowing and unknowing, have contributed to the research and development of the external cavity diode lasers and electronics at MOG Laboratories. Special thanks to Keith Nugent, Leo Holberg, Jamie White, Anton Barty and Jolanda van de Ven and to former students Lincoln Turner, Karl Weber, Colin Hawthorn, Sebastian Saliba, Mirek Walkiewicz, Chris Vale and Phil Fox. Most of all my thanks go to Alex Slavec, an engineer with Fig. 8. Current model of the MOGLabs controller, laser and legendary insight and expertise in electronics, and remarkable pa- photodetector. More than 100 controllers have been sold around tience with a physicist’s concept of a commercial-ready design. the world. References The Future [1] P. Hannaford, ‘Alan Walsh 1916–98’, Hist. Records Aust. Sci. 13(2) (2000) 179– Why do it? Why take an idea, or an instrument design, from the 206. lab, and try to sell it around the world? It is another adventure; [2] C. J. Hawthorn, K. P. Weber and R. E. Scholten, ‘Littrow configuration tunable physics is only a small part of making the business work, which external cavity diode laser with fixed direction output beam’,Rev. Sci. Instrum. means that there have been a lot of new things to learn. Of course 72 (2001) 4477. it is satisfying to see that other people care about your work, [3] L. D. Turner, K. P. Weber, C. J. Hawthorn and R. E. Scholten, ‘Frequency noise characterisation of narrow linewidth diode lasers’, Opt. Commun. 201 (2002) 391. ‘Contemplating the inventor’s [4] S. D. Saliba and R. E. Scholten, ‘Linewidths below 100 kHz with external cavity share of the royalties, we started diode lasers’, Appl. Opt. 48 (2009) 6961–66. looking at holiday homes in the Bio Robert Scholten is an Associate Professor and exclusive Victorian beach resort Reader in Physics at The University of Mel- bourne, where he leads the Ultracold Plasma of Sorrento…’ high-brightness electron source Programme of the ARC Centre of Excellence in Coherent X-ray Science. His research career began with enough to pay for it, and to be manufacturing high-tech equip- studying electron collisions from laser-excited atoms, where the ment in Australia. It has brought new connections to similar re- laser polarisation controlled the quantum state of the target atoms. searchers around the globe, and better instrumentation in my own His interest in the laser-atom interactions formed the basis of his lab. The rewards are intangible: it has never been about making further research, for example using atom-optics techniques for money – but at the same time, we want to develop new products, nanofabrication as a Fulbright Postdoctoral Research Fellow at and employ more staff, and move into larger premises, so the con- NIST in the USA. He has also developed novel approaches to op- cern for financial matters is never far away. tical imaging of cold atoms, is currently working on quantum MOGLabs is now five years old. It has grown without advertis- sensing using colour centres in diamond, and has created a high- ing, without government assistance, without private investment tech start-up company (MOGLabs) based on lasers and laser and without venture capital. Organic growth has allowed steady electronics.

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A Bonsai Black Hole in Our Own Backyard

Robert Soria

The discovery of powerful jets from a nearby black hole reveals new clues about the behaviour of massive quasars in the early universe.

Black holes are popularly portrayed as a place of darkness and gloom, but to as- Radio image of Fornax A, an iconic radio galaxy with extended lobes (orange). The tronomers they are the cleanest and most grey region between the lobes is stellar light from the much smaller host galaxy (from Formalont et al. [1]). efficient source of energy in the universe. The recent discovery of a very large glowing bubble of ionised gas inflated and heated by a black hole in the nearby galaxy NGC 7793 helps us to understand their role as cosmic powerhouses. While stars use nuclear fusion to extract energy from their gas, black holes extract gravitational energy from the infalling mat- ter before it disappears into the hole – a process known as accretion. Indeed hydro- gen bombs and hydro power plants are based on the same physical principles as stars and black holes, respectively. Hydro power may seem less efficient than nuclear fusion. While it takes a lot of falling water to produce the same energy as we would get from nuclear fusion, this is only because the gravitational field of the Earth is so weak. But gravity near a black hole is much stronger, and accretion power can be up to 50 times more efficient than nuclear fusion. the process. When photon output domi- jets or winds? What switches the jet on and This is why black holes – or, more ex- nates, a black hole appears as a very lumi- off? These are still unsolved mysteries of actly, the gas in the region immediately out- nous source, especially in the X-ray and black-hole astrophysics, but this is where side the black-hole horizon – can be the ultraviolet bands. A supermassive black our recent discovery of the most powerful most luminous and powerful objects in the hole in the centre of a galaxy, with a mass stellar-mass black hole jet 12 million light universe when enough matter is falling to- that is many millions of times the mass of years away in NGC 7793 will help to pro- wards them. The end result is that black the Sun, can be more luminous than all the vide some answers. holes get bigger over time as long as there stars in that galaxy put together. is matter to fuel them. Alternatively, accretion power can be Radio galaxies and The general energetics of black-hole ac- carried out by a collimated jet of charged microquasars cretion is known from fundamental physi- particles – either electrons and , One of the best things about black holes is cal principles, but there are still many or electrons and protons – moving at al- that their fundamental physical properties important things we do not know about most the speed of light. are the same at all scales. Supermassive how that energy is released. The two main A third ingredient may also be present, black holes in distant quasars work just like channels are radiation of photons and the especially in the most active black holes: a stellar-mass black holes in our galaxy, apart kinetic energy of a jet. dense wind launched from the surface of from a simple rescaling in the equations. The photons are emitted from the sur- the accretion disk can carry away mass, en- What changes is the environment around face of an accretion disk that is formed by ergy and angular momentum. them, such as whether their fuel comes gas that is slowly spiralling towards the How does a black hole decide whether from galaxy-scale gas inflows or a compan- event horizon – and is getting very hot in to release its accretion power via photons, ion star.

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Cygnus A is a classic radio galaxy comprising a pair of collimated jets, hot spots and lobes (from Carilli and Barthel [2]).

From an astronomer’s point of view, a black hole in its centre. Today, we have in- X-ray band. The rest of the jet power is crucial advantage of nearby stellar-mass dependent evidence of black holes with jets transferred to the ambient gas as thermal black holes over their more distant and from infrared, optical and X-ray studies, energy and used to inflate the hot cocoon. massive cousins is that they evolve over but radio observations still provide the best Microquasars are the stellar-mass equiv- shorter timescales and can switch between spatial resolution and are not affected by in- alent of radio galaxies. They are powered by jet, disk and wind states within the terstellar absorption. a black hole formed from the collapse of a timescale of a university research grant. Su- Powerful black-hole jets share a common massive star. They contain a pair of relativis- permassive black holes may be bigger and structure. They drill through the surround- tic jets that interact with the interstellar gas brighter, but they switch states over tens of ing gas until they lose enough energy or hit and may produce bright hot spots, radio millions of years. denser interstellar material. A shock front lobes and an expanding cocoon or cavity. Over the past two decades, much work forms at the slowly-advancing head of the Radio observations of the inner jet and has been done to understand the connec- jet and is often visible as a bright ‘hot spot’ outer lobes have been a crucial tool for dis- covering and studying radio galaxies and microquasars, but calculating the total jet “From an astronomer’s point of view, a power from its radio emission is not simple. crucial advantage of nearby stellar-mass The swirling cloud of radio-emitting elec- trons carries only a small and poorly- black holes over their more distant and known fraction of the total power. The rest is transferred from the jet to the surround- massive cousins is that they evolve over… ing gas, which is heated and swept out, forming a hotter, lower-density bubble the timescale of a university research grant.” around the black hole. This is what deter- mines the full impact of the black hole’s ac- tions between astrophysical objects that in several energy bands. When the relativis- tivity on the surrounding gas, but it is once seemed totally unrelated but are all tic jet particles reach the shock front, their difficult to observe this effect directly. powered by active black holes. Radio galax- orderly bulk motion is converted into ran- ies and microquasars are among the most dom motion and the collimation of the jet The most powerful spectacular examples. stream is lost. microquasar ‘Radio galaxy’ is, in fact, a poorly chosen After going through the shock front, This is why an object such as the recently name. The ‘radio’ label comes from their electrons backflow and disperse into a large, discovered black hole S26 in NGC 7793 is initial discovery from radio observations in fluffy lobe around the end of the jet, and so important. Our team, led by Dr Man- the 1950s: it was not known at the time sometimes form a full cocoon around the fred Pakull at the University of Strasbourg, that the radio emission is produced by rel- black hole. As they swirl around magnetic used optical and X-ray observations to re- ativistic electrons in a jet. And the ‘galaxy’ field lines, the electrons emit synchrotron veal the hot spots at the end of the symmet- label is misleading: it is not the galaxy that radiation – mostly in the radio bands but ric jets, and the hot bubble of gas around produces the jet, it is the supermassive sometimes extending also to the optical and the system. The bubble is expanding at a

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speed of 250 km/s. The jets are driving the expansion of the bubble, pushing its shell as they slam against the denser and cooler interstellar medium. Strong radio emissions from the jet lobes and the cocoon were dis- covered from our observations in 2009 and 2010 at the Australia Telescope Compact Array at Narrabri in NSW. This object contains the largest bubble and the longest jets ever seen from a stellar black hole, with a total length of about 1000 light years. Furthermore, they are emitted from a black hole that is at most a few hundred kilometres in diameter. We estimate that the active phase of this black hole started around 200,000 years Left: radio image at 3-cm wavelength of the newly discovered microquasar S26 in NGC ago – the blink of an eye in the history of 7793. The red arrows mark the trajectory of the two jets, travelling in opposite directions the universe. During this short period of from the black hole. The brighter regions (hot spots) at the end of the jets are where the time, the black hole has swallowed as much fast jet particles hit the surrounding interstellar gas and dissipate their energy. Right: the gas as there is in the Sun, and has produced emission from ionised Helium reveals the location of hot gas (heated by the jets) in the 300 times more energy than will be emitted same system (from Soria et al. [3] and Pakull et al. [4]) by our star over its entire lifetime. Having measured both the radio emis- do not, even if they are accreting at the yard. It is heating and sweeping the gas sion from the relativistic electrons and the same rate and have the same total power? around it, much like quasars did on a heating effect on the surrounding gas, we How do black holes switch from one state grander scale billions of years ago. If some could then estimate the total jet power. It to the other? quasars can output a significant fraction of is a few hundred times the power carried by One suggestion is that black-hole spin their power through jets – instead of, or in the radio-emitting electrons alone. determines the jet power. Rapidly spinning addition to, photons – they would be more This is more than previously thought. It black holes would more likely produce efficient at heating the ambient gas and makes S26 one of the most powerful stellar stronger jets or retain their jets at high ac- would have a stronger effect on the evolu- black holes – including both jets and pho- cretion rates, all other conditions being the tion of their host galaxies. ton output – by an order of magnitude. It same. This is at least in qualitative agree- Modelling the interaction between also means that we may have underesti- ment with what is seen in other astrophys- black-hole growth and galaxy evolution will mated the total jet power of many other ical objects (e.g. protostars, stars), be a key science goal of the Australian black holes, especially in the distant uni- where jets are more often launched by fast- Square-Kilometre-Array Pathfinder verse, if we only measured their luminous spinning bodies. (ASKAP) radio telescope being built near output. Spin is the most elusive property of a Geraldton, WA, in synergy with infrared It was previously thought that radio jets black hole, and is even more difficult to and X-ray studies. were only associated with moderately weak measure than its mass. If we could measure black holes, while jets could not be both the mass and the spin of an active Robert Soria is a Senior Research launched by black holes that are growing black hole we could test crucial predictions Fellow at the Curtin Institute of Radio very fast (i.e. when a lot of gas is falling into of general relativity and learn more about Astronomy, Perth them). In other words, at low accretion black-hole formation and growth. Different rates, black holes would produce jets, while formation channels predict different spin [Reprinted from Australasian Science at high accretion rates they would have a values, so it would be extremely interesting magazine, March 2011] luminous disk. if the jet power of black holes is indeed an The discovery of S26 – and similar re- indicator of their spin. References cent discoveries of a few jet-dominated, Regardless of the mechanisms for jet for- [1] Fomalont et al., Astrophys. J. Lett. 346 (1989) 17. powerful quasars in the distant universe – mation, the observed existence of very pow- [2] Carilli and Barthel, Astron. Astrophys. Rev. 7 have challenged this scenario. It seems now erful black-hole jets has profound (1996) 1. that at least some of the most powerful implications for the early history of the uni- [3] Soria et al., Mon. Not. Roy. Astron. Soc. 409 black holes can have strong jets. verse. During the first billion years or so the (2010) 541. cosmos was dominated by quasars, which [4] Pakull, Soria and Motch, Nature 466 (2010) 209. Black-hole spin and jets are the most powerful state of supermassive But a fundamental problem remains un- black holes in the nuclei of galaxies. How- solved: why do some of the most powerful ever, the quasar phase ended after most of black holes – both in the stellar-mass and their gas supply was exhausted. supermassive class – have jets while others S26 is a bonsai quasar in our own back-

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Walter Boas Medal for 2010

laboratory and technological environments. Plasma Nanoscience: For example, interstellar dust nucleates in the relatively cold envelopes of red giant From Controlled Complexity stars, where the gas temperature and the ionisation degree are suitable for condensa- tion of carbon atoms that are produced and to Practical Simplicity ejected by the stars. At this stage, nanopar- ticles of solid matter are created; this Kostya (Ken) Ostrikov process is affected by the plasma environ- ment. Relevant plasma-specific phenomena include ion-induced nucleation, turbulent Physicists are often asked to explain the significance, flows, vapour supersaturation, among oth- novelty, and most important scientific points of their ers. As another example, low-temperature research work. More precisely, they are commonly plasmas are used for microstructuring semi- expected to clarify the ‘excitement created by the scientific conductor wafers in microelectronics, dep- novelty and approach’ and the ‘significance and outcomes’ osition of functional coatings, films and of their work. interlayers, surface hardening and modifi- cation, etc. Fabrication of tiny features in semiconductor wafers involves many plasma-specific effects such as surface These simple points set the framework to What do we do in Plasma charging, reactive ion etching, ion bom- structure, perform, and communicate sci- Nanoscience? bardment, production of reactive radicals entific reseach in a way that generates new In an attempt to provide a relatively simple by electron-impact processes, just to men- knowledge and scientific excitement on one and concise answer to this question, it tion a few. one hand and leads to some practically would be fair to state that myself and many As a third example, which will be con- meaningful outcomes on the other. Put of my colleagues and collaborators do re- sidered in greater detail below, carbon nan- simply, one could pose the question “what search in the field of Plasma Nanoscience otube nucleation and growth benefits from is new in what you do and why it is useful?” to find new plasma-specific mechanisms to microscopic electric fields near the surface, This needs to be clearly answered to satisfy control complex organisations of atomic electron- and ion-assisted production of our curiosity and to maintain the interest matter at sub-nanometre to microscopic carbon atoms from hydrocarbon precur- and excitement of all the categories of lis- scales to develop new materials, devices, sors, plasma-specific localised heating, and teners and readers, ranging from profes- and processes for energy conversion, elec- some other effects. These and many other sional colleagues to the general public and tronics/IT, health care, environmental and effects make low-temperature plasmas truly school students. other applications that are critical for a sus- unique environments for nanoscale synthe- tainable future. Even more concisely, we are sis and processing. Not surprisingly, in What is Plasma Nanoscience? trying to control the plasma-related complex- many applications, plasma-based nano- Plasma Nanoscience is a multidisciplinary ity to eventually achieve the practical simplic- tools have shown superior performance research field which aims to elucidate the ity in applications, which is also reflected in compared with techniques primarily based specific roles, purposes, and benefits of the the title of this article. Our research also on neutral gas chemistry, such as thermal ionised gas (plasma) environment in assem- aims at explaining some natural phenom- chemical vapour deposition (CVD). bling and processing nanoscale objects in ena that are affected by the plasma- and natural, laboratory and technological situ- nanoparticle-related effects. Why make things more ations and to find the most effective ways Without trying to exhaustively cover complicated? to ultimately bring these plasma-based even a small subset of relevant physical phe- Compared to neutral gas-based routes, in processes to the deterministic level [1]. The nomena and practical applications, here we low-temperature weakly-ionised plasmas concept of the deterministic plasma-based will only highlight a few typical examples there is another level of complexity related nanoscale synthesis and processing is based and consider one of these examples in more to the necessity of creating and sustaining on finding the most optimum plasma detail using the framework of “what is new a suitable degree of ionization and a much process parameters to minimise the number in what you do and why it is useful?” larger number of species generated in the of experimental trials one needs to under- Our research simultaneously involves gas phase [1]. Furthermore, in many cases take to achieve nanostructures and nano- low-temperature plasmas, nanoscale ob- it is very challenging to control the genera- materials with the desired properties, which jects, or mesoscopic objects with nanome- tion, delivery and deposition of a very large in turn determine their performance in tre features. Situations where the plasma number of radical and ionic species. This is practical applications. meets small solid or liquid objects are nu- further complicated by intense physical merous and can be found in many natural, (physisorption, sputtering, etc.) and chem-

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ical (chemisorption, bond passivation, re- ~1–2 eV depending on the nanotube size active ion/radical etching) plasma–surface and catalyst material) to diffuse through the interactions. This higher level of complexity catalyst nanoparticles and then to be incor- leads to a number of practical difficulties in porated into the developing tubular struc- operating and controlling plasma-based ture. It is believed that the nanoparticle size processes and provokes an obvious ques- determines the thickness of the SWCNT. tion: “Why do we need more complex, The thinner the nanotubes, the stronger plasma-based systems if it is possible to pro- is the quantum confinement of electrons duce nanoparticles using wet chemistry or and more unique size-dependent quantum other relatively simpler means?” effects can emerge. However, it is more Years of research in the Plasma challenging to grow very thin nanotubes. Fig. 1 A typical plasma–solid system Nanoscience field has provided many con- Indeed, nanoparticles of smaller radii tend used in the growth of single-walled carbon vincing examples where an investment into to produce stronger internal tension which nanotubes (SWCNT), showing the plasma– producing a more complex, ionised gas en- effectively pushes the incoming carbon surface interactions. vironment has led to significant advantages atoms back to the substrate. This phenom- in terms of energy efficiency, quality, repro- enon is known as the Gibbs-Thompson ef- ducibility, and safety of the fabrication and unzipping carbon nanotubes, synthesis fect, which strongly affects the nucleation processes, on one hand, and superior nano- of nanomaterials with exotic superstruc- and growth or a broad range of inorganic material structure, properties, and perform- tures, porosity, nanocrystalline inclusions, one-dimensional nanostructures. ance on the other. It is not surprising that surface topology, reactivity, to mention just Consequently, as the catalyst nanoparti- the discovery of carbon nanotubes, the a few [3]. cles get smaller, the barriers that carbon most common basic building blocks in atoms need to overcome increase. As a re- present-day nanotechnology, was made How to grow nanotubes and sult, the substrate temperatures required to using thermal plasmas of arc discharges [2]. where are the challenges? supply this energy need to be increased Other non-exhaustive examples relate to Let now consider an example of plasma- even further. Such higher surface tempera- significantly reduced process temperatures, based growth of single-walled carbon nan- tures are not only well above the presently control over species production and dy- otubes in more detail (see Fig. 1). First of tolerable process temperatures in microelec- namics in the gas phase and solid surfaces, all, SWCNTs have generated a lot of excite- tronics (and some other areas), but also lead very high energy efficiency, charge- and ment in the last decade owing to their to the strong diffusion of the catalyst ma- magnetic field-related driving forces for unique structural, electronic, mechanical, terial into the substrate. In some cases this self-organisation, possibility of commercial- optical and other properties. The unprece- diffusion consumes the whole catalyst scale nanoparticle production, unique ver- dented toughness and electron conductivity nanoparticle even before the nanotubes tical alignment of one-dimensional make SWCNTs perhaps the most struc- start growing. To prevent this, thin inter- nanostructures, effective control of nano- turally stable one-dimensional supercon- layers such as SiO2 are used. However, material properties by the process parame- ters, unique plasma-enabled nanostructures and growth regimes impossible otherwise, “It is not surprising that the discovery of dry ultra-fine precision etching and writing of virtually any nanoscale features includ- carbon nanotubes… was made using ing very high aspect ratio and straight trenches for nanoelectronics, finely confor- thermal plasmas of arc discharges” mal coatings of micro- and nanoscale fea- tures with any required thickness down to ducting nanomaterial of the future. SiO2 is a dielectric material and represents a single monolayer or even sub-monolayer Nanotubes are commonly synthesised an obvious obstacle to achieve ohmic loss- coverage, property-transforming (e.g. con- using metal or metal alloy catalyst nanopar- free direct integration of carbon nanotubes ducting to semiconducting) surface func- ticles (e.g. Fe, Co, Ni, Au and alloys such into the presently dominant silicon-based tionalisations of various nanostructures as Fe–Ni) with a suitable lattice spacing, nanodevice platform. Moreover, thermally including single-walled carbon nanotubes carbon solubility, and melting temperature. grown SWCNTs often feature structural (SWCNTs) and graphene, production of In thermal CVD processes, hydrocarbon defects, are twisted and tangled and, as thermodynamically unfavourable precursors (methane, acetylene, etc.) are de- well, are very randomly oriented on the metastable structures and nanophases, in- composed to produce carbon atoms on the substrate. Furthermore, it is not presently tricate self-organised nanopatterns on a va- hot surface of a substrate material such as known how to control the chirality, which riety of substrates ranging from metals, Si. This process requires a very significant is the angle of twist of a wrapped graphene ceramics, and semiconductors to flexible external heating, up to 900–1000°C and sheet that makes up the nanotube. and temperature-sensitive surfaces, the as even higher. This heat is used to produce Therefore, the major scientific challenges recently elusive possibility to control the carbon atoms and give sufficient energy to in this direction are to: (1) drastically re- ‘uncontrollable’ chirality of SWCNTs, for- a fraction of them to overcome quite sig- duce the growth temperatures; (2) min- mation of graphene nanoribbons by cutting nificant potential barriers (of the order of imise the amount of building material and

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energy used to achieve the desired growth plasma systems are used for this purpose tures. Depending on the energy, ions can rates; (3) prevent catalyst diffusion into the (see Fig. 2). In this case, the plasma is sep- deposit in different sections of the nan- substrate without using intervening layers; arated from the substrate and only a small otubes and on the substrate surface be- (4) vertically align the nanotubes on the amount of material is delivered to the tween the nanostructures. Since the ion substrate and eventually achieve regular growth surface. This arrangement also re- energy is determined by the potential drop three-dimensional nanoarrays; (5) achieve duces the effect of burying the catalyst par- across the plasma sheath, selective ion dep- energy-efficient nucleation and growth of ticles or the short nanotubes at the early osition can be effectively controlled by the very thin nanotubes; (6) enable chirality growth stages by amorphous (carbon in this plasma parameters and the substrate bias. control of SWCNTs; and, if possible, (7) case) material. This is a common problem This leads to the unique possibility to se- eliminate the need to use any catalyst at all. in the catalysed growth of a large number lectively deposit ion fluxes in the specified of one-dimensional nanostructures such as areas, with nanometre (and possibly even nanotubes, nanowires, nanotips, etc. higher) precision. In the SWCNT case con- As shown in Fig. 1, the plasma bulk is sidered, it is desirable to deposit the ions separated from the surface by the area of onto (or as close as possible) the catalyst uncompensated space charge termed the nanoparticle, which is located at the nan- plasma sheath. In low-temperature non- otube base. This will lead not only to the equilibrium plasmas, the electrons have faster delivery of carbon species to the cat- much higher energy than the ion or neutral alyst, but also to stronger and faster localised species. Thus, many reactive species can be heating of the catalyst nanoparticles. This created in the ionised gas phase by electron- localised heating reduces even further the impact reactions. In the carbon nanotube minimum external substrate heating (and growth, carbon atoms need to be produced hence the substrate temperatures) required from hydrocarbon precursors such as CH4, for the nucleation and growth. In addition, C2H2, and some other gases and gas mix- several ion-assisted processes facilitate the tures. In thermal CVD, these processes production of carbon atoms directly on the mostly take place on the surface; thus, very SWCNT surface (see Fig. 3). The carbon Fig. 2. The remote plasma reactor at the high surface temperatures that are sufficient atoms produced in this way can diffuse Plasma Nanoscience Centre, CSIRO for the effective hydrocarbon dissociation along the nanotube surface and also be in- Materials Science and Engineering, at are required. The strong thermal non-equi- corporated into the growing tubular struc- Lindfield, NSW. The reactor is used for plasma-assisted growth of delicate librium of the plasma makes it possible to ture through the catalyst nanoparticle. The nanoscale objects such as carbon generate the needed atomic and radical carbon atoms and other radicals can also nanotubes, graphene, silicon quantum species in the plasma bulk and therefore easily detach/evaporate from the nanotube dots and inorganic nanowires. substantially (e.g. several hundred Kelvin) and the substrate surfaces. Therefore, lower reduce the surface temperatures needed for surface temperatures in the plasma-based Can we help you? Yes we can! nanostructure growth. This in turn dramat- SWCNT growth also substantially reduce This is where various Plasma Nanoscience ically reduces the rates of metal catalyst dif- the rates of material losses thereby increas- approaches based on the unique properties fusion into the substrate. ing the matter and energy efficiency in the of low-temperature plasma–solid systems Furthermore, due to a very high mobil- nanoscale synthesis process. (Fig. 1) are used to solve the above scientific ity of electrons, the surfaces are at a nega- Fig. 3 shows many other elementary challenges. However, reasonable care tive potential compared to the plasma bulk. interactions between the plasma-generated should always be exercised in the plasma- Therefore, there are non-uniform electric species and the single-walled carbon nan- based growth of single-walled carbon nan- fields within the plasma sheath; the electric otube. The number of elementary reactions otubes. For instance, to minimise any field lines start in the plasma bulk and con- that lead to the nanoscale transfer of energy possible damage to the delicate single- verge to the sharp tips of the developing and matter on the surface of the nanotubes walled structure of the nanotubes through one-dimensional nanostructures. This leads is very large and is usually larger than in bombardment by energetic ions, remote to strong ion focusing by the nanostruc- neutral gas-based processes. In particular, a

Fig. 3. The complexity of subnano- and nanoscale interactions of low-temperature plasmas with a single-walled carbon nanotube, showing the principal processes of energy and matter transfer [4]: A – adsorption; D – desorption; E – evaporation; TD – thermal dissociation; IAD – ion-assisted dissociation; SR – surface recombination; HAD – hydrogen-assisted desorption; SD-CNT – surface diffusion on the carbon nanotube surface; SD-S – surface diffusion on the substrate surface; and WI – incorporation of carbon atoms in the nanotube walls. The following processes are related to nanoscale transfer of energy: Hph – energy transfer from the plasma to the SWCNT; HL – energy transfer from the SWCNT to the plasma (energy loss); Hsh – energy transfer to the SWCNT due to external substrate heating; Hsph – energy transfer to SWCNT due to the surface heating by the plasma; HIB – energy transfer to the SWCNT due to plasma ion bombardment; and finally HR – energy transfer to the SWCNT due to exothermic SR.

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lead to a superior quality of number of applications. Indeed, having the nanostructures produced. very high conductivity, metallic SWCNTs For example, the level of can serve as inter-level (and other) conduct- structural defects in SWC- ing connections in nanoelectronics; appro- NTs produced in arc dis- priately (e.g. selected-area) doped charge plasmas is usually semiconducting SWCNTs can be used as lower compared with many tiny p–n junctions for photovoltaic energy wet chemical and neutral gas conversion; interconnected SWCNT net- thermal processes. In addi- works offer tantalising prospects to achieve tion, charging and polariza- unprecedented nanoscale connectivity in tion of the nanotubes new-generation, non-silicon-based nanode- substantially improve their vices; unique hydrophobic properties make alignment, most prominently plasma-processed carbon nanotube arrays Fig. 4. Some applications of plasma-made nanomaterials in the direction of the electric ideal candidates for the advanced field within the plasma drug/gene/protein delivery systems; and and microscopic plasma–surface interactions. sheath. Since this electric carbon nanotube arrays have been demon- field is normal to the substrate sur- strated as the darkest matter that can absorb face, the nanotubes also align in the almost 100% of the incident light. These same direction. This is why this ef- are just a few examples among the many re- fect is usually referred to as the ver- ported applications that benefit from the tical alignment of one-dimensional unique nanotube properties arising from nanostructures. The electric field their size, dimensionality and structure. alignment effects appear to be The plasma-based synthesis offers many stronger for the multi-walled CNTs possibilities not only to improve the nan- and substantial efforts are still re- otube quality and the energy-, matter-, and quired to obtain very regular arrays cost-efficiency of the synthesis processes, of vertically aligned SWCNTs. but also to uniquely post-process (e.g. coat, The two issues of control of functionalise, etc.) the nanotube surfaces to SWCNT chirality and complete enable additional controls of their elec- Fig. 5. Photovoltaic solar cell technology for elimination of the catalyst remain tronic, optical, bio-compatibility, and other renewable energy generation relies heavily on among the greatest scientific chal- properties. plasma-based nanoscale processes. Quantum-dot lenges for the coming years. Figs 4 and 5 show further examples of nc enhanced photoactive -Si functional layers, Plasma-produced Fe–Ni metal alloy the applications of plasma-made nanoma- nanostructured ZnO transparent conducting oxide layers, and plasmonic arrays of Au nanoparticles are catalyst nanoparticles [5] as well as terials and microscopic plasma processing. advanced features of the next-generation solar the application of external magnetic In addition to the multipurpose CNT ar- energy conversion devices. fields lead to substantial improve- rays discussed above, these non-exhaustive ments in the SWCNT chirality dis- examples include carbon nanowire connec- very large number of electron- and ion-as- tributions. On the other hand, our tions between Ag nanoparticles for the ‘self- sisted processes, not common to neutral experiments suggest that the exposure of organised’ electronics of the future; regular gas-based thermal processes, are involved. small features directly written on a Si wafer arrays of highly-luminescent quantum dot Therefore, the complexity of the plasma– to high-density plasmas enables a com- arrays for the energy-efficient, ultra-bright surface interactions at the nanoscales is pletely catalyst-free growth of multi-walled solid-state light emitting sources; ultra- higher compared to neutral gas-based carbon nanotubes. This possibility, without nanoporous metal-oxide nanowires for processes. any (e.g. metal or oxide) catalysts or artifi- photochemical hydrogen production and Nevertheless, this complexity leads to cially carbon-enriched layers, still awaits its nanofluidics; ultra-sensitive environmental the better energy- and matter-efficiency of realisation for SWCNTs. sensors based on plasma-produced iron the plasma-based nanoscale synthesis It is noteworthy that plasma-based ap- oxide and other inorganic nanowires; processes. It is important to stress that the proaches bring many other new and excit- nanostructured hydroxyapatite coatings of above features make it possible to also ing features into nanoscale synthesis and hip and joint implants for reconstructive achieve much higher rates of the nanostruc- processing. This is why we hope that the surgery; as well as cellular control via mi- ture nucleation and growth compared with above discussion answers the first part of croscopic plasma–cell interactions for the many other nanofabrication processes. the question: “what is new in what you do?” improved bacterial sterilisation, biofilm re- Moreover, localised nanoparticle heating ef- moval, wound healing, blood coagulation, fects lead to the possibility of nucleation of Why is it useful? and even highly-selective treatment of ma- much thinner one-dimensional nanostruc- Let us now try to answer the second part of lignant (e.g. melanoma) cells in cancer tures, thus mediating the adverse Gibbs- the question, namely “why is it useful?” The therapies. Thompson effect mentioned above. carbon nanotubes discussed above show a Fig. 5 shows the structure of a photo- In many cases plasma-based processes truly outstanding potential for a very large voltaic solar cell of the next generation

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based on plasma-made functional layers. photo-generated carriers, enabling multiple Moreover, everyone is welcome to en- The main photo-conversion layer is made exciton generation (MEG) by a single en- gage in this exciting and rapidly emerging of nanocrystalline Si (nc-Si). Such layers, re- ergetic photon, and other exciting physical research field and collaborate with us and cently produced in reactive low-tempera- effects. Importantly, these physical effects colleagues from our large international net- ture plasmas, contain fairly regular represent a significant scientific challenge work. I take this opportunity to thank all three-dimensional arrays of tiny Si and are expected to generate exciting mul- my coauthors and collaborators, as well as nanocrystals with a reasonably uniform size tidisciplinary research in the coming years. the international Plasma Nanoscience re- distribution, which is very difficult to search community for their contributions achieve otherwise. Transparent conducting Where there is a will there is a and support. oxide (TCO) layers made of the plasma- way produced ZnO offer excellent light trans- An important point to stress is that by References doing fertile research in the Plasma [1] K. Ostrikov, ‘Plasma Nanoscience: Basic Concepts Nanoscience field we are trying to learn and Applications of Deterministic how to control complex plasma-based Nanofabrication’ (Wiley–VCH, Weinheim, processes, during nanoscale synthesis and Germany, 2008). “… the next- processing, to produce new nanomaterials [2] S. Iijima, Nature 354 (1991) 56. generation solar cells that in turn enable new functionalities in [3] K. Ostrikov, ‘Control of energy and matter at new-generation nanodevices. Most impor- nanoscales: Challenges and opportunities for are expected to tantly, these materials and devices should plasma nanoscience in a sustainability age’, J. Phys. be reliable, effective, energy- and cost-effi- D: Appl. Phys. 44 (2011) (in press). significantly enhance cient, as well as reasonably simple in the [4] K. Ostrikov, ‘Nanoscale transfer of energy and the efficiency and practical applications envisaged. This is matter in plasma–surface interactions’, IEEE Trans. why I particularly want to emphasise the Plasma Sci. (2011) (in press). reduce the cost of need to ultimately aim to achieve the prac- [5] W. H. Chiang and R. M. Sankaran, Nature Mater. tical simplicity (a ‘will’) by learning how to 8 (2009) 882. photovoltaic control complex physical phenomena (con- trolled complexity – a ‘way’) at the atomic Bio renewable energy and nanometre scales (e.g. nanoscale con- Kostya (Ken) Ostrikov generation” trol of energy and matter by using the is a CEO Science plasma-specific effects). Leader, ARC Future It is also imperative to emphasise that Fellow, and a founding plasma-based nanotechnology is among the leader of the Plasma parency and very high electrical safest nanotechnologies and offers a safe Nanoscience Centre Australia at CSIRO conductivity; the latter can be effectively nanofabrication environment with much Materials Science and Engineering at Lind- controlled using plasma-assisted doping. reduced nanoparticle toxicity risks and field, NSW. His achievements include the The arrays of Au nanoparticles in turn fur- lower exposure to hazardous gases and awarded by the Australian ther enhance light capture via the surface chemicals. Academy in 2008, eight prestigious fellow- plasmon-related forward scattering effect. Finally, I believe that the non-exhaustive ships in six countries, three monographs Plasma-assisted magnetron sputtering is a arguments in this article suggest that doing and more than 280 refereed journal papers very effective tool not only to produce such research in Plasma Nanoscience is indeed and 80 plenary, keynote and invited talks two-dimensional arrays, but also to control something new, exciting, challenging, use- at international conferences. His research the size- and position-distribution of the ful, and also safe. I also hope that these ar- on nanoscale control of energy and matter nanoparticles within the arrays. guments have shed some light on the in plasma–surface interactions contributes These features of the next-generation question “what is new in what you do and to the solution of the grand and as-yet un- solar cells are expected to significantly en- why is it useful?” and will generate interest resolved challenge of directing energy and hance the efficiency and reduce the cost of among researchers irrespective of their field, matter at the nanoscale, a challenge that is photovoltaic renewable energy generation. academic rank or background and will also critical for the development of renewable This is expected to be achieved by the effec- urge them to direct their research efforts in energy and energy-efficient technologies for tive use of photons from the entire solar their own fields from controlled complexity a sustainable future. He can be contacted spectrum, minimising energy losses of the to practical simplicity. at [email protected].

118 Australian Physics Volume 47, Number 5, September/October 2010 AustPhys_475 20/04/11 11:46 PM Page 119

How Much Free Will Do We Have?

Quantum mechanics may be even spookier than we thought, as Tim Wetherall reports

In a Bell inequality scenario, a measurement made on one such entangled particle causes both it and its twin to instantly condense into a single real state, even if the two are separated by vast distance.

Quantum mechanics is inherently statisti- One of the key features of quantum me- inequality’ paper proved that any hidden cal in that it can tell you the probability of chanics is that each such emitted particle variable theory for quantum systems, in something like a nucleus emitting an alpha exists in a superposition of every possible which observers had free will to choose particle in a given time, but it can’t tell you state until a measurement is made, at which what they measured, was forced to have exactly when or how. In the early days of point they condense into a single real state. such spooky interactions! quantum mechanics this caused great con- In this way, it is the actual process of mak- Of course people immediately began to sternation for many scientists, including ing measurements that in effect ‘creates’ re- ask whether a Bell inequality scenario, or Einstein whose dislike of this apparent ran- ality – strange but true. something like it, could be used to create domness prompted him to protest “God Conservation rules also dictate that if the faster than light communication. The basic does not play dice!” spin of one such emitted particle is up, then idea being that a pair of quantum entan- Einstein and others, proposed what’s that of its twin must be down. But of gled particles are sent in opposite directions now known as hidden variable theory, to course until a measurement is actually from a location midway between two dis- get some causality back into the quantum made, each particle has both spin up and tant observers. If a measurement is made world. In essence this says that there are down at the same time. Physicists call this on one, perhaps by an alien civilisation in mechanisms within the nucleus that lead to quantum entanglement – two particles a distant galaxy, that would instantly affect the emission of the alpha particle in a de- whose states depend on each other but the state of its twin here on Earth so surely terministic way, but we can’t see them so where both particles still exist in all possible that’s faster than light communication they appear random to us. However in states because no measurement has yet been right? 1964, the physicist John Bell published a made on them. Unfortunately the universe doesn’t work famous paper in which he argued that no In a Bell inequality scenario, a measure- that way. The problem is, that although the hidden variable theory can reproduce all of ment made on one such entangled particle effect may be instant, if we measure the the observed quantum phenomena. causes both it and its twin to instantly con- spin of our particle as up, we don’t know if A well-known and intriguing aspect of dense into a single real state, even if the two the aliens caused that by measuring theirs Bell’s work are known as Bell inequalities. are separated by vast distance. This notion as down, or if it was our own measurement Bell proposed a situation in which some- was also intensely disliked by Einstein, who that condensed the state. There are exactly thing like the decay of a nucleus emits two termed it “spooky interaction at a distance”. as many ups as downs, so there is no way particles simultaneously that move in op- However, Bell showed Einstein could to tell. To find out you would have to send posite directions. not have his cake and eat it too. His ‘Bell a message to the aliens and ask them what

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ness with which an experimenter chooses when and where to measure. In other words your free will might not be as free as you think! “My model sidesteps Bell’s theorem, by allowing the same underlying variable that predetermines the measurement outcomes to have a small statistical influence on the choices of measurement made for each par- ticle. This influence – known as ‘measure- ment dependence’ – is not directly observable but leads to the correct quan- tum correlations.” Of course that slight statistical shift in the ‘free’ choices made by the measurer are not limited to human experimenters. If a random number generator were used, there may also be a shift in its choices though sta- tistically the numbers it created would ap- pear perfectly random. How could this still appear random? Well imagine tossing a coin four times. Heads, heads, tails, tails is statistically as probable as heads, tails, heads, tails. The first might be influenced by measurement dependence the second not – how would you know? Such an effect may have implications for quantum cryptography which relies on en- Dr Michael Hall is patent examiner at IP Australia in Canberra. In his spare time he is a tanglement to send secure signals. If some- visiting fellow at the ANU Department of Theoretical Physics. one taps into the system, the entanglement is lost and the eavesdropper is sprung. they did and of course that would have to Dr Hall has recently published a paper “Quantum cryptography is basically be at sub-light speed. It would seem there- [1] in the prestigious journal Physical Re- fore that no faster than light signalling or view Letters suggesting that if you give up sound from a physics point of view, but our information transfer is possible. However just a little experimental free will you can work opens up the question of the sending that’s not to say that the physics of Bell in- accurately model a Bell inequality using the and receiving devices being tampered with. equalities is not interesting. kind of deterministic hidden variable If someone has ‘monkeyed’ with your One scientist looking into the interpre- physics Einstein might have loved. equipment, you may be exposed to data tation of quantum mechanics and what “I’m looking at what’s known as a re- leaks hidden within the seemingly random might or might not be possible within Bell laxed Bell inequality, that is one in which statistics, without that being at all obvious.” In a strange coincidence, Hall and Ein- stein have more in common than an inter- “I comfort myself with the thought that, est in hidden variable theories. In addition to his visiting fellowship at the ANU, Hall while I’m not as good a physicist as Einstein, is also currently working as a patent exam- I’m a better patent examiner!” iner. “I comfort myself with the thought that, while I’m not as good a physicist as Einstein, I’m a better patent examiner!”, he inequalities is Dr Michael Hall, a visiting the need for absolute free will is relaxed says. fellow at the ANU Department of Theoret- slightly. Do that, and you can make it work ical Physics. According to Hall: “It’s been deterministically without evoking faster Tim Wetherall is editor of ScienceWise shown that you can’t have no-signalling, de- than light signalling.” magazine, published by the ANU terminism and experimental free will all to- If this is indeed how the universe oper- College of Physical Sciences gether in a world described by quantum ates, the very strange implication would be mechanics. You have to give up some or all that the apparent randomness in the spin of at least one. But how much of each one orientation of entangled particles may be References is a really interesting question.” weakly coupled to the apparent random- [1] M. J. W. Hall, Phys. Rev. Lett. 105 (2010) 250404.

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Book Reviews The works of Meissner, Ginzburg, Lan- What is immediately apparent in reading dau, F. and H. London, Bardeen, Cooper this book is the author’s passion and knowl- and Schrieffer are woven into a vivid journey edge for this subject. The fervour with which leading towards our, as yet, imperfect under- he writes, particularly in chapter five regard- standing of the superconductivity phenom- ing the possible new directions and exciting enon. Brilliant highlights including the new understanding of reality that may be Josephson effect, and the discovery of the obtained from the LHC, is infectious almost ‘high-temperature superconducting’ rare- as though through the LHC we will drink earth oxides, occupy several chapters. The from the Holy Grail itself. main text is supplemented by no less than 20 The work, which is divided into five pages of detailed Notes, and a comprehensive chapters, plays out as having the reader enter Index. into the science surrounding the LHC. The Whether as a serious history, or as an en- audience for which the book is written seems joyable weekend read, this book provides ex- to be the non-expert in particle physics and cellent value for content, entertainment, and begins with a general appeal to the reader quality. The air of disillusionment which has who has an interest in the current directions set in over superconducting applications in of science. Some knowledge of the periodic recent years is honestly conveyed, and does table, atoms, their components and indeed not in any way diminish the excitement of the standard model of matter would be ben- earlier chapters. The Cold Wars is highly rec- eficial, although not essential. ommended to interested laymen, teachers The book then moves into the startling The Cold Wars: A History of and students alike. revelation that there is a deep uncertainty as Superconductivity to what the LHC will discover. Discussion By Jean Matricon and Georges Waysand on topics such as the Higgs boson, super- Rutgers University Press, 271 pp., $US25 symmetry and what is the smallest particle Translated from the French by Charles Glashausser in the universe is both stimulating and con- Reviewed by John Macfarlane, CSIRO Lind- textualising in understanding the purpose of field the LHC. This is an eminently readable book, although The book moves into the practical side of a couple of years out of date by now, with how this will be achieved by explaining how which to celebrate the Centenary Year of Su- accelerators work, and what makes the LHC perconductivity. Originally published as a different from those that have gone before. French-language text in 2003, the recent It is in chapter four, particularly the second translation by Glashausser brings a fascinating half of the chapter, where the detail of the history to a deservedly-wider audience. Start- book while interesting for the technical as- ing with a brief outline of earlier nineteenth pects presented may swamp the non-physi- century milestones in the production of low cist reader who only seeks to understand the temperatures by pioneers such as Faraday, general concepts that the creators of the ma- Joule, Kelvin and Dewar, the human aspects chine wish to use it for. The work closes with of the development of supercon duct ivity re- a discussion on much broader issues that sci- search that was triggered in 1911 by Kamer- entists are currently tackling. The strength of lingh Onnes are brought to life. We learn, for the work lies within the striking detail and example, that Onnes gave insufficient credit understanding that the author is able to to the contribution of an assistant, Gilles The Quantum Frontier: bring to bear in discussing this area of inter- Holst, who had actually carried out the cru- The Large Hadron Collider est. cial electrical measurements. By Don Lincoln My criticism of the book is its uneven Johns Hopkins Press, $25 The ‘Cold Wars’ of the title is appropriate ISBN 978-0-8018-9144-1 emphasis on the various aspects the author also to the political scene of the times, with Reviewed by Lee Weissel, Wagga Christian Col- wishes to cover. It is as though you wade into an account of how Kapitza was encouraged lege the work only to discover that later on you by Rutherford to leave the Soviet Union to This book takes on the daunting task of seek- perhaps should have brought more resources establish the Mond Laboratory in 1933 at ing to explain the existence and purpose of with you, as it can seem to suddenly become the , England. Stalin that magnificent scientific machine known deep. Overall though, The Quantum Frontier subsequently ordered Kapiza back to as the Large Hadron Collider (LHC). The can be thoroughly recommended for an in- Moscow, along with much of his Cambridge author Don Lincoln is himself a scientist troduction to the LHC and to the contem- equipment. Kapitza was nevertheless instru- with the Fermi National Accelerator Labora- porary frontiers of science. It is a work to mental in securing the release of Landau, tory and also author of a previous book, Un- whet the appetite of those enthusiasts in who derived a theory of superfluidity, from derstanding the Universe: From Quarks to the physics that a paradigm changing discovery prison in 1940. Cosmos. could be just around the corner.

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Obituary Marshall Stoneham 1940–2011

Hamish Johnston

The theoretical condensed-matter physicist Marshall Stoneham died on 18 February 2011 at the age of 70. Stoneham, who was a fellow of the Royal Society, spent much of his career studying the effects of defects in solids and published several books on the topic. In October 2010 he took over as president of the Institute of Physics, which publishes Physics World. His duties for the Institute will for the moment be taken over by the Institute’s immediate past-president Jocelyn Bell Burnell. Stoneham was born in Barrow-in-Furness on 18 May 1940. He completed a PhD in physics at the University of Bristol in 1965 and spent much of his career at the UK Atomic Energy Research Establishment (AERE) in Harwell, Oxfordshire, where he led the solid-state and quantum-physics group of the theoretical division between 1974 and 1989. The following year he was appointed di- rector of research at AEA Industrial Technology and later took up the position of chief scientist of AEA Technology. In 1995 Stoneham moved to University College London, where he became director of the university’s interdepartmental Centre for Materials Research. With his wife Doreen, who is also a physi- cist, Stoneham founded Oxford Authentication Ltd in 1997 and remained a director at the time of his death. The small firm uses thermoluminescence techniques to establish the provenance of earthenware, stoneware, porcelain and the casting cores of bronzes. Stoneham also served as vice-president of IOP Publishing, the publishing arm of the Institute, and was editor-in-chief of the In- stitute’s Journal of Physics: Condensed Matter. In his spare time, Stoneham was an enthusiastic French horn player and even pub- quantum-information technology and hoped to create solid-state lished two books in this area. He is survived by his wife Doreen quantum gates that are compatible with silicon and could operate and two daughters. In a statement, the Institute said that “he will at room temperature. Stoneham was also involved in various proj- be greatly missed by the physics community, and by all of us in ects linking physics and medicine, including one that sought to the Institute”. understand how humans can discriminate between different scents Stoneham had a wide range of research interests, including the and whether left- and right-handed versions of chiral molecules electronic structure of defects, the properties of surfaces and inter- should smell the same or not. faces, the true nature of scanning-probe microscopy and diamond films. However, in recent years he had taken a growing interest in Hamish Johnston is an editor of physicsworld.com.

122 Australian Physics Volume 47, Number 5, September/October 2010 AustPhys_475 20/04/11 11:46 PM Page 123

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124 Australian Physics Volume 47, Number 5, September/October 2010 AustPhys_475 20/04/11 11:46 PM Page 125

Latest News from timate stability and drop-shipment capa- quired. The power scalable approach of the Toptica Photonics bility DL RFA SHG pro also offers solutions for • Direct modulation and fast switching be- other high power applications such as Multi-Colour Systems – Multi-Laser tween wavelengths sodium LIDAR, medical therapy or super Engines and Tunable VISible Lasers • True one-box solution with integrated resolution microscopy. Customised systems electronics with higher output powers up to 10 W are • Unique features: COOLAC, FINE and available on request. Wavelengths between SKILL technology 560 and 620 nm will soon be available as • Most compact and cost effective solution customised solutions. for multicolour biophotonic applications FemtoFiber pro – Three exciting new systems are now available iChrome TVIS the product family from Toptica: Our ultrachrome picosecond laser is: i s • Continuously tunable in the visible range expanded iChrome MLE-L of 488 – 640 nm After the successful Multi Laser Engine with up to three diode • Fibre coupled output (single-mode) introduction of the lasers and one DPSS Laser fully integrated in • Fully automated operation FemtoFiber pro one compact box. • Pure colour, narrow emission bandwidth IR, NIR and SCIR • Multi-line laser with up to four laser lines (< 3 nm) models, TOPTICA is now taking the final • Wavelengths diode lasers: 405, 445, 488 • Perfectly suited for fluorescence lifetime step to also include the remaining system and 640 nm (375, 473, 660, 785 nm and imaging microscopy (FLIM) or optical variants such as tunable visible (TVIS), tun- others on request) testing of components able near-infrared (TNIR) and tunable ultra • Wavelengths DPSS laser: 532 and 561 The iChrome TVIS laser system is a fibre compressed pulse (UCP). Options such as nm (505, 515, 594 nm and others on re- laser with the flexibility to set automatically variable repetition rate (VAR) and a phase- quest) the laser output to any wavelength in the vis- locked loop Laser Repetition rate Control ible (488 – 640 nm). The coherent laser out- (LRC) by TOPTICA’s well-established PLL- iChrome MLE-S put ensures that the visible light exhibits the electronics are rounding up the FemtoFiber All-diode Multi Laser Engine with up to four best intensity noise performance and the use pro product family. diode lasers fully integrated in one compact of polarisation maintaining optical compo- The first and fastest of the new models, box. nents a stable linear polarisation of the fibre UCP, shows short pulses in the range down • Multi Line Laser with up to four diode coupled output beam is achieved. The entire to 13 fs, the fastest available on the market laser lines laser system is extremely user friendly: No from a turnkey SAM modelocked fibre laser • Available wavelengths: 405, 445, 488 and alignment procedures of any optical compo- system. 640 nm (375, 473, 660, 785 nm and oth- nents distract the user from the main task – The TVIS expands the super-continuum ers on request) to produce results. generation (SCIR) by a tunable second har- • High free-space and fibre coupled output monic generation and allows transferring power levels DL-RFA-SHG pro @ 589nm 2 Watt, femtosecond pulse generation into the visible single line for sodium cooling wavelength range from 490 to 700 nm. Common to both MLE models The TNIR variant finally adds a new fea- The individual lasers are efficiently combined ture to the FemtoFiber pro family. As op- and delivered free beam or via an all-in-one posed to the TVIS, it uses the high-band PM/ SM fibre output. The microprocessor continuum (>1560 nm) for second har- controlled system enables flexible OEM in- monic generation. This continuum part is a tegration. High speed analogue and digital solitonic pulse and therefore needs no pulse modulations allow fast switching of laser compression. The output wavelength can be wavelength and intensity. tuned from 800 to 1100 nm. This variant TOPTICA’s ingenious COOLAC technol- was not previously available in the FFS prod- ogy automatically aligns the system with a The new DL RFA SHG pro is a narrow-band uct family. single push of a button. This feature ensures tunable continuous wave laser for sodium a constant optical output level even under cooling. The system is based on a near-IR For more information please contact Lastek strongly varying ambient conditions and diode laser in the successful ‘pro-design’ (DL at [email protected] completely eliminates the need for manual 100/pro design, 1178 nm), with a subsequent Lastek Pty Ld realignment - making the iChrome MLE the Raman fibre amplifier (RFA) and a resonant Adelaide University - Thebarton Campus most advanced multi-line laser system on the frequency doubling stage (SHG pro). 10 Reid St, Thebarton, SA market. The DL RFA SHG pro features a spectral Aus 1800 882 215; NZ 0800 441 005 • Single mode, polarisation maintaining linewidth below 1 MHz and 20 GHz mode- T: (61 8) 8443 8668; F: (61 8) 8443 8427 fibre output or free beam COOLAC tech- hop free tuning. For system operation, no email: [email protected] nology for highest coupling efficiency, ul- water cooling and no external pump is re- web: www.lastek.com.au

Australian Physics Volume 47, Number 5, September/October 2010 125 AustPhys_475 20/04/11 11:46 PM Page 126

Warsash Real-Time Operating System for Systems E-618: 3.2 kW Peak Power for New Piezo Lightweight Benchtop Vibration Isolation Integration Amplifier

PI (Physik Instrumente), the leading man- Available from Warsash Scientific is the ufacturer of piezoceramic drives and posi- new PI (Physik Instrumente) E-618 high Warsash Scientific is pleased to announce a tioning systems, offers a real-time module power amplifier for ultra-high dynamics new lightweight benchtop vibration isola- as an upgrade option for the host PC and operation of PICMA® piezo actuators. tion system from Kinetic Systems, Inc. also the connection of the GCS (PI General The amplifier can output and sink a Specifically designed for portability, the Command Set) software drivers. The mod- peak current of 20A in the voltage range ELpF can be easily repositioned on the ule is based on Knoppix-Linux in conjunc- between -30 and +130V. The high band- benchtop, even with a load and in float. Its tion with a pre-configured Linux real-time width of over 15kHz makes it possible to unique, self-contained design provides this extension (RTAI). exploit the dynamics of the PICMA® actu- without causing damage to the vibration The use of real-time operating systems ators. This type of performance is required isolators. on the host PC allows it to communicate in active vibration cancellation and fast An economical alternative to heavy- with other system components, e.g. a vision valve actuation applications. weight models, the Ergonomic Low-Pro- system, without time delays with discrete The E-618 also comes with a tempera- file-Format platform provides vibration temporal behavior and high system clock ture sensor input to shut down the ampli- isolation for sensitive devices. It features a rate. fier if the maximum allowed temperature load capacity of 100 or 300 lbs. in a light- A library which is 100% compatible of the piezo ceramics has been exceeded. weight, ergonomic system. with all other PI GCS libraries is used for This is a valuable safety feature given the ex- The platform has a low profile (only 3” the communication with the real-time sys- tremely high power output. high), uses a small tabletop (16” x 19” stan- tem. All PI GCS host software available for The E-618 is available in several open- dard), and weighs 40 lbs., making it very Linux can be run on this system. loop and closed-loop versions with ana- portable. Ergonomic features include The real-time system running in the real- logue and digital interfaces. gauges tilted upward for easier viewing and time kernel can be used to integrate PI in- recessed handles for easy carrying. terfaces and additional data acquisition For more information on these and the Designed for use in laboratories and boards for control. Open functions to en- range of other PI products, contact Class 100 cleanrooms, the ELpF platform able you to implement your own control al- [email protected] is ideal for supporting atomic force micro- gorithms are provided. Data, such as Warsash Scientific Pty Ltd scopes, microhardness testers, analytical positions and voltages, is recorded in real Tel: +61 2 9319 0122 balances, profilometers, and audio equip- time, and pre-defined tables, with posi- Fax: +61 2 9318 2192 ment. tions, for example, are output in real time www.warsash.com.au Self-leveling and active-air isolation give to the PI interface and to additional data the platform low natural frequencies (1.75 acquisition boards. New Sensors Improve Precision of S-340 Hz vertical, 2.0 Hz horizontal) and typical You can program your own real-time Tip/Tilt Mirror isolation efficiencies of 95% (vertical) and functions in C/C++, MATLAB/ 92% (horizontal) at 10 Hz. SIMULINK and SCILAB. Other tabletop sizes can be customized The system includes a PI GCS server, per specifications. The top, which can be which allows the system to be operated as ordered with or without mounting holes, a blackbox using TCP/IP, via a Windows can be aluminum plate, ferromagnetic computer, for example. stainless steel, plastic laminate, or anti-static The system can be installed on a PC or laminate. booted directly as a live version from the data carrier. A free demo version with re- For more details on this or other vibration stricted functionality is available. Warsash Scientific is pleased to announce isolation equipment, contact the release of the new S-340 piezo tip/tilt [email protected] For more information on the real time mirror platform from PI (Physik Instru- operating software or other PI positioning mente), equipped with new high-resolution equipment, contact [email protected] strain gauge sensors.

126 Australian Physics Volume 47, Number 5, September/October 2010 AustPhys_475 20/04/11 11:46 PM Page 127

The S-340 now achieves a resolution of The camera includes the improved Su- • Dark gray GUI reduces monitor bright- 20nrad at angles of 2mrad about both or- perSynchro timing generator, SyncMaster ness; monitor dims automatically during thogonal axes. clock output, a compact ‘one-box’ design, acquisition This large mirror platform is used for op- convenient GigE interface and much, • All experimental parameters are saved to tics with diameters of up to 100 mm (4 much more. data file headers - no more searching old inches) and achieves a resonant frequency notebooks for data acquisition settings of 900Hz for a mirror of 50 mm diameter. For further information please contact Paul • Automatic light saturation warning with The S-340 can be operated by the new, Wardill on pseudocolour low-cost E-616 controller. Together, they [email protected]: • Multiple regions of interest can be de- form a compact, high-performance solu- Coherent Scientific fined in a single window tion for beam control and image stabiliza- 116 Sir Donald Bradman Drive, Hilton SA • Save and reload experimental settings tion as employed in astronomy, laser 5033 and share between multiple users machining or optical metrology, for exam- ph: (08) 8150 5200 ; fax: (08) 8352 2020 • Configurable setting dock holds pre- ple. www.coherent.com.au ferred commands • Control multiple cameras via multiple For more information on the S-340 instances of LightField Tip/Tilt Mirror platform or other Position- • Drag-n-drop data into Excel, Paint and ing equipment from PI, contact Notebook or export to TIFF, FITS, CSV [email protected] etc. • Peak find function works with both nar- row and broad lines Coherent • IntelliCal provides up to ten times im- proved accuracy

For further information please contact Paul Wardill on [email protected]: PI-MAX3 Intensified CCD Cameras Light-Field 64-bit Acquisition Software Coherent Scientific Princeton Instruments’ PI-MAX series of From the world leaders in optical spec- 116 Sir Donald Bradman Drive, Hilton SA intensified CCD cameras has set the stan- troscopy and CCD/EMCCD/ICCD tech- 5033 dard for time-resolved imaging and spec- nology comes LightFieldTM, an all-new ph: (08) 8150 5200 ; fax: (08) 8352 2020 troscopy for almost a decade. Now 64-bit data acquisition platform for spec- www.coherent.com.au Princeton’s PI-MAX3 takes ICCD per- troscopy and imaging. LightFieldTM com- formance to a new level with order of mag- bines complete control over Princeton nitude speed improvements and a host of Instruments’ cameras and spectrometers new features to allow easier and more accu- with easy-to-use tools for experimental rate time-resolved imaging. setup, data acquisition and post-processing. LightfieldTM ensures data integrity via eXcelon…CCD and EMCCD sensitivity automatic saving to disc, time stamping redefined and retention of both raw and corrected Princeton Instruments and Photometrics data with full experimental details saved in are pleased to announce the launch of new each file. LightFieldTM works seamlessly eXcelon back-illiminated charge-coupled in multi-user facilities, remembering each device (CCD) and electron-multiplication user’s hardware and software configurations CCD (EMCCD) detector technology that and tailoring options and features accord- will revolutionise scientific imaging and PI-MAX3 is available in formats of 1024 ingly. The optional, patent-pending Intel- spectroscopy. x 1024 pixels for imaging and 1024 x 256 liCal package is the highest-performance New eXelon sensors provide excellent pixels for spectroscopy. Video frame rates wavelength calibration software available, photon-detection capabilities across a wide can be achieved in the imaging format and providing up to ten times greater accuracy spectrum, from 200 to 1100nm, and are spectral rates of thousands of spectra per across the entire focal plane than compet- particularly beneficial for applications re- second can be achieved. Most importantly, ing routines. quiring enhanced sensitivity in the blue and the camera allows sustained gating rates up Features include: near-infrared (NIR) region, as illustrated to 1 MHz, a 20-fold improvement over • Immediate data acquisition upon launch below. In addition, eXcelon back-illumi- previous designs. • Progressive disclosure - contextual nated sensors significantly reduce etaloning menus ensure that only relevant options (the problematic appearance of fringes). appear When eXelcon technology is applied to • Graphical hardware configuration EMCCD devices, the result is a detector builder ensures that system elements with sub-electron read noise, superb sensi- work exactly as the end user expects tivity, low dark current, little (if any)

Australian Physics Volume 47, Number 5, September/October 2010 127 AustPhys_475 20/04/11 11:46 PM Page 128

etaloning and high frame rates. These new eXcelon-enabled cameras will For further information please contact Paul New eXcelon technology will be fea- target a wide variety of applications in both Wardill on [email protected]: tured in Princeton Instruments’ PIXIS and the life and physical sciences. Examples in- Coherent Scientific ProEM deep-cooled cameras and is avail- clude astronomy, Raman spectroscopy, live- 116 Sir Donald Bradman Drive, Hilton SA able in several pixel-array formats: cell imaging confocal imaging, total 5033 • 1340 x 100 and 1340 x 400 CCD cam- internal reflection fluorescence microscopy ph: (08) 8150 5200 ; fax: (08) 8352 2020 eras for spectroscopy (TIRFM), Forster resonance energy trans- www.coherent.com.au • 512 x 512 and 2048 x 2048 for imaging fer (FRET), Bose-Einstein condensate The technology is also available in 512 x (BEC) imaging, solar cell inspection, as 512 and 1024 x 1024 ProEM EMCCD well as super resolution techniques such as cameras. STORM and PALM.

Physics Decadal Plan

The Australian Academy of Science is overseeing the development of a new Decadal Plan for Physics. The AIP has been charged with the responsibility of running the process of developing the plan. A similar process was last run in 1993 which produced the publication ‘Physics: A Vision for the Future’. The Australian Research Council has granted funds to support the development of the new plan. Michelle Simmons (UNSW), in her role as the Chair of the Academy of Science National Committee for Physics, has appointed David Jamieson (UMelbourne and past AIP president) to convene a Working Group to take the process to the next stage. The Working Group includes Hans Bachor (ANU), Cathy Foley (CSIRO), Ian McArthur (UWA), John O’Connor (UNewcastle), Halina Rubin- sztein-Dunlop (UQueensland), Brian James (USydney and past AIP president). The Working Group has been busy interviewing a large number of physicists in academia, CSIRO, DSTO, ANSTO, schools, in- dustry, government, representative organisations and many other segments of the physics community. There was also a second interview process to establish the research resource requirements of the various physics sub-disciplines and their views on what the big opportunities for research are for the next 10 years. From these interviews the common issues affecting all will be identified and specific requirements for solutions will be developed. The Decadal Plan consists of two broad components. The first is an inward looking component which will consist of a survey of Physics in Australia today to show how the discipline has evolved since 1993 and identify the significant areas of activity andexpertise. The second is a forward looking component that aims to identify emerging opportunities that can be highlighted and developed. eTh Plan aims to have a broad audience and will serve to make the excitement and potential of Physics in the twenty-first century accessible to a wide audience. Both components have called for comment and vision from the Physics community through a website, town hall meetings and the call for white papers. The deadline for submission of white papers was the beginning of April 2011. Most important has been the op- portunity for delegates to the 2010 AIP Congress last December to present their views at dedicated sessions that were held during the Congress week. A further six months of consultation and review will follow before the draft plan, provisionally titled ‘Investing in the future of Physics’ which will be presented to the Academy in July 2011. Further information is available at http://www.physicsdecadalplan.org.au/home.

128 Australian Physics Volume 47, Number 5, September/October 2010 AustPhys_475 20/04/11 11:46 PM Page 129

Conferences

29 May – 3 June 2011 22 – 31 August 2011 Fourth International Conference on Chaotic Modelling, Simula- URSI General Assembly and Scientific Symposium of Interna- tion and Applications tional Union of Radio Science Agios Nikolaos, Greece Istanbul, Turkey

28 June – 1 July 2011 13 – 20 August 2011 Twenty-fifth International Union of Geodesy and Geophysics IQEC/CLEO Pacific Rim 2011 (IUGG) General Assembly: Earth on the Edge Sydney Melbourne Convention & Exhibition Centre 28 August – 1 September 2011 1 – 3 July 2011 International Conference on Nanoscience & Technology, Chi- Astronomical Society of Australia’s Harley Wood Winter School naNANO 2011 Adare House, Victor Harbor, SA Beijing

4 – 8 July 2011 7 – 9 September 2011 Astronomical Society of Australia’s Annual Science Meeting Thirty-sixth Annual Condensed Matter & Materials Meeting University of Adelaide, SA Charles Sturt University, Wagga Wagga

4 – 8 July 2011 31 January – 3 February 2012 Fifteenth International Conference for Women Engineers and Sci- Queensland Astronomy Education Conference (QAEC) entists (ICWES15) Brisbane Adelaide Convention Centre, SA 25 February 2012 19 – 22 July 2011 Thirty-sixth International Conference on High Energy Physics, American Association of Physics Teachers (AAPT) 2011 Summer ICHEP2012 Meeting Melbourne Convention and Exhibition Centre Omaha, Nebraska 4 – 11 July 2012 30 July – 3 August 2011 Nuclei in the Cosmos 2012 Twenty-second General Assembly and Congress of the Interna- Cairns Convention Centre, Qld tional Union of Crystallography (IUCr) Madrid 5 – 10 August 2012 Fifteenth International Conference on Small-angle Scattering, SAS 2012 Sydney

Subscribe to Physics World

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Australian Physics Volume 47, Number 5, September/October 2010 129 AustPhys_475 20/04/11 11:46 PM Page 130

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116 Sir Donald Bradman Drive, Hilton SA 5033 Phone (08) 8150 5200 Coherent Fax (08) 8352 2020 Freecall 1800 202 030 [email protected] SCIENTIFIC www.coherent.com.au