CavMag Newsletter Winter 2009 January 2011 Issue 5 News from the Cavendish Laboratory

Inside... £20 million donation to Editorial 2 revolutionise physics research Ferroelectric and Magnetoelectric Memories 2 David Harding (St Catharine’s, 1979, new technologies and new industries that will The Raymond and Beverly Natural Sciences), the Founder, Chairman be needed to meet the demands of a growing Sackler Fund for the and Head of Research of Winton Capital population on our already strained natural Physics of Medicine 3 Management, has pledged to donate £20 resources. The programme’s director is Richard million to the Cavendish Laboratory to Friend, the Cavendish Professor of Physics Nanomagnetism 4 set up and fund The Winton Programme and a world-renowned leading expert on the John Baldwin FRS for the Physics of Sustainability. His gift, physics, materials science and engineering (1931 – 2010) 5 the largest donation to the Laboratory of semiconductor devices. Remarking on Higgs Bosons Provide since its creation in 1874, will create a new the impact of the donation, Richard said: Bridges to Hidden Worlds 6 programme in the physics of sustainability, “Advances in fundamental physics have always applying physics to meet the growing had the capacity to solve very real problems. Athena SWAN Silver demand on our natural resources. This programme will support the people and IoP Juno Champion with the radical ideas Success 7 that bring practical From the Hubble to solutions - very much the James Webb Space the Cambridge way of Telescope 8 doing science.” The Lloyd’s Register Educational Trust supports The programme will students in Scientifi c provide studentships, Computing 9 research fellowships, and support for new New Workshop Course for academic staff as Graduate Students 10 well as investment in Developing the Cavendish research infrastructure Development Plan 10 of the highest level, pump-priming Cavendish News 11 David Harding for novel research Senior Physics Challenge, projects, support for Physics at Work & the “The Cambridge 800th Anniversary Campaign collaborations within the University and outside, Science Festival 2011 12 has an objective: ‘The Freedom to Discover’ and sponsorship for meetings and outreach and I am hoping I can give the scientists of the activities. Cavendish more freedom to discover,” says David Harding. “I studied theoretical physics at Since graduating from Cambridge in 1982, Cambridge, and the Cavendish has always had David Harding has become one of the most the reputation of attracting the fi nest minds successful fund managers in the world. Early in the world. While it is not quite as simple on he recognised the advantages of hiring as using physics to save the world, this is an individuals with science backgrounds. Winton opportunity to use, for example, quantum currently employs over 90 researchers with physics to develop materials with seemingly PhDs or Master’s Degrees in subjects including miraculous properties that could combat the extragalactic astrophysics, mathematics, growing effect humans are having on the statistics, particle physics, planetary science and planet. I want to encourage research to keep artifi cial intelligence. the skies blue.” “At its core Winton is much more than an The Vice-Chancellor, Professor Sir Leszek investment manager,” says David Harding. Borysiewicz, said: “The University is most “We are a scientifi c research centre using grateful to David for this donation, which is empirical methods to analyse data. The fi nancial truly exceptional both in its generosity and in its markets may be our laboratory but just like the vision of translating fundamental discoveries in Cavendish we are driven by research.” physics, to meet one of the most pressing needs of our generation.” The Winton Programme for the Physics of The donation will support programmes that Sustainability will launched and fully established www.phy.cam.ac.uk explore basic science that can generate the in 2011. Editorial Ferroelectric and Magnetoelectric Memories

his edition’s news is dominated or about twenty is shown in Fig.2. The physics interest of by the magnifi cent donation years there such structures lies in how to optimize the Tby David Harding described Fhas been a dielectric layer of the ferroelectric material, on the front page. The Winton perceived need in in the example shown in Fig. 2 the layer Fund will support research in the microelectronics being made of lead zirconate-titanate. the general area of what we call industry, not just These devices have already had commercial the physics of sustainability. The for faster, cheaper success. For example, FRAMs are used in intention is to support a very wide memories of higher the Sony Playstation 2. range of fundamental and applied bit-density, but especially for non-volatile physics in the general area of memories. ‘Non-volatile’ means that the condensed matter physics, which stored information is not lost in the event is fostered by many groups in the of, for example, a power failure or if a Cavendish. All of these activities nuclear blast goes off in front of your will contribute to understanding intercontinental ballistic missile, or more commonly the cat trips over the power cord how physics can contribute to the on your PC. The way most computers work many sustainability challenges is with dynamic random access memories that society is facing worldwide. (DRAM). DRAMs are silicon chips that are We will also use the resource to very cheap, very fast, and very high density, facilitate collaborations with other but they are volatile. So it is not a good idea departments in Cambridge and our to store a million bank accounts in them, partner universities. A distinguished or even the fi rst draft of your dissertation. international management group In your PC, the information is processed in will be set up to oversee these DRAMs, but when you hit the SAVE key, activities. The formal opening of the it is stored on a hard disc that is slow but programme will take place in the fi rst non-volatile. If the DRAMs were replaced quarter of 2011. by a non-volatile equivalent, the hard disc could be eliminated resulting in smaller, At the same time, we are delighted to lighter, and far more robust computers with Fig. 2. The interior of each bit of the state- announce gifts from the Raymond and no moving parts. You could put such a the-art Samsung 64 Mb FRAM. Beverly Sackler Foundation to support computer in a tank, into a basketball, or into research in the Physics of Medicine and in-line roller skates... Basic physics problems have, however, the Lloyd’s Register Educational Trust for limited the commercial exploitation of this studentships in Computational Science. technology. Every two or three years the These are described later in this edition industry giants in microelectronics - IBM, of CavMag. Texas Instruments, Intel, and Motorola in the USA; Samsung and LG Electronics in The science theme of this edition is Korea; and a host of Japanese corporations ‘New Faces’. Recent appointees Jim such as Hitachi, Toshiba and Fujitsu - publish Scott, Russell Cowburn and James Wells an ‘Industry Roadmap’ which shows what describe their research activities, each the industry needs in the coming few of them bringing new approaches and, years. The road-map for 2005 required unquestionably in James’ case, extra the development of FRAMs with three- dimensions to the Laboratory’s research Fig. 1. A Samsung packaged ferroelectric dimensional, rather than two-dimensional portfolio. We wish them all success in random access memory. structures by 2010-2011. This is because their endeavours. the bit-density is limited by the capacitor One way to replace DRAMs is with non- area, or ‘footprint’, on the chip surface. In A notable achievement has been the volatile ferroelectric RAMs (FRAMs). conventional RAMs that involve resistors award of Athena SWAN Silver and IoP In a ferroelectric crystal, the ions can be and transistors, the areas involved are much Juno Champion Awards in recognition of displaced in two or more directions by smaller than those of the capacitors in our endeavours in Equal Opportunities, applying an electric fi eld of order 50 kV/cm. FRAMs. That is a strong fi eld, but across a thin fi lm particularly in the support of female One way to get round this problem is to members of staff. only 100-300 nm in width, it is a very small voltage, in fact, less than the 5V standard of fabricate three-dimensional nanotube all silicon chips. capacitors that stick out of the silicon Lastly, we have simplifi ed the way in chip and we have achieved this in a which gifts to Physics may be received In work I did in the 1980s at the Ramtron collaboration of various Cambridge online and this is described on page Corporation and Symetrix Corporation in University laboratories (Fig. 3). Using organic 10. We are most grateful to the the USA, we were the fi rst to make such ruthenium compounds we can fabricate Development Offi ce for making this ferroelectric memories. A good example good concentric electrodes inside and possible. We hope benefactors will fi nd of a packaged FRAM from Samsung is outside each tube, giving a large area, and this an effective way of helping with our shown in Fig. 1. This consists of eight 512 proportionately large capacitance, but a development efforts. kbit blocks each of which has 16 32-kbit small footprint. A related approach is to go sections. The interior of each bit of the down, not up, by fabricating deep trenches Malcolm Longair state-of-the-art Samsung 64 Mb FRAM with high aspect ratios (Fig. 4).

2 These materials are usually multiferroic, meaning magnetic and ferroelectric, and The Raymond and so there is the concept of writing the data electrically, which is very fast, voltage-driven Beverly Sackler not current-driven, and uses very low power, and reading the information magnetically Fund for the which involves no re-set operation, no fatigue and no endurance problems. Physics of Medicine Present work in several Cambridge groups, including Montu Saxena, Gil Lonzarich and myself in the Cavendish and Mathur and his colleagues in Materials Science is exploring Fig. 3. Three-dimensional nanotube such magnetic ferroelectric devices. The capacitors on a silicon chip. physics is however much harder. We need An alternative approach is to fabricate to address question such as: Why are tiny nano-dots, which are best studied there no materials that are ferroelectric and by electron holography. Fig. 5 illustrates strongly magnetic at room temperature? such holography of magnetic nano- Will ionic fl uorides or oxyfl uorides have domains. Related studies are underway on different physics from multiferroic oxides? ferroelectric nano-dots in an EPSRC funded What exactly is the coupling mechanism collaboration between Cambridge and between magnetism and ferroelectricity? Belfast. These are demanding questions that are at the forefront of physics research – watch this space! The newest approach is to try to make memories out of thin fi lm magnetoelectrics. Jim Scott Dr Raymond and Mrs Beverly Sackler.

e are delighted to report a benefaction of £2m to be received Wover the next four years or earlier from the Raymond and Beverly Sackler Foundation. This benefaction has been provided as a tribute to the Vice-Chancellor Emerita, Professor Dame Alison Richard. In recognition of this generous gift, an area in the new Physics of Medicine Building at West Cambridge will be named the Raymond and Beverly Sackler Research Centre in the Physics of Medicine.

The income of the Fund will be used to promote and encourage research in the Physics of Medicine by initiating studies into innovative research ideas. In addition, it will be used in supporting student training and Fig. 4. Another approach to creating nanotube capacitors by fabricating deep trenches in exchanges of staff at all levels in the fi eld of the substrate. Physics of Medicine, including international exchanges, internal secondments to the Centre for Physics of Medicine, summer schools, and in supporting visitors to the Physics of Medicine programme. It will also provide Graduate Studentships in the Physics of Medicine, as well as furthering scientifi c discussion and exchange among those carrying out research in the fi eld of Physics of Medicine in the University through seminars, early stage project development, international exchanges, and collaboration.

The University has benefi ted enormously from the generosity of Raymond and Beverly Sackler. Among the benefi ciaries closest to physics, their provision of the lecture theatre in their name at the Institute of Astronomy and the Annual Sackler lectures in Astronomy and Medicine are of particular signifi cance. In Medicine the Raymond and Beverly Sackler Medical Research Centre has Fig. 5. Holographic images of nano-domains (courtesy of Richard Harrison, University of been established for many years within the Cambridge). Faculty of Clinical Medicine in the University.

3 magnetic materials contain a large number of domains, separated by boundaries Nanomagnetism known as domain walls. Domain walls are very tangible – they have a size and a mass, they can be seen using either light t is fourteen years or electrons, and can be pushed around since I completed by magnetic fi elds or electrical currents. Imy PhD at the Most importantly, they can be injected Cavendish in the into a nanowire, a long strip of magnetic Physics and Chemistry material just a few atoms thick and tens of Solids group. I have of nanometres wide, like a marble into a now returned to the copper pipe. I have been interested in such Cavendish, having spent domain walls for many years – one of my time in Paris, Cambridge current interests is to see if they can be used Engineering, Durham and Imperial College for detecting the results of biological assays, London. My research interests cover the potentially leading to ways to detect cancer areas of nanotechnology, magnetism and and other diseases by a low-cost portable optics. Magnetism and nanotechnology chip (Fig. 2). go together very well, both for scientifi c discovery and technological applications. The second project concerns the physics that Nanotechnology is all about materials that underpins computer memory. An article in have been structured on length scales of The Economist in 2008 reported that the 1-100 nm (1nm equals 10-9 m), resulting in carbon footprint of computer data centres modifi ed physical properties. Materials are is set to overtake that of aircraft within 10 sensitive to such modifi cation for two main years. Reducing the power consumption reasons. Firstly, the ratio of surface area to of computers is therefore an important part Fig. 1. A laser sensor (top) that probes volume within the material can be changed of tackling climate change. Most of the the naturally-occurring roughness present by nanostructuring – an extreme version waste heat generated by computer chips in virtually all real surfaces such as of chopping up vegetables to make them comes from quantum mechanical tunnelling paper (middle) and plastic (bottom) and cook more quickly! Surfaces usually possess of electrons through regions that should which has now been developed into an very different physical properties because be electrical insulators. My research aims anti-counterfeiting and anti-smuggling the atoms at the surface have a different to fi nd new ways of using nanostructured technology known as Laser Surface symmetry from those in the bulk. Secondly, magnetic materials within chips to counter AuthenticationTM. many of the fundamental physical processes that underpin the properties of materials have a characteristic length scale of a few nanometres. For example, electrical conductivity is determined by how far an electron travels between scattering events. If we modify the material on that length scale then we disrupt those fundamental processes. In magnetism, both the surface to volume ratio and the characteristic length scales are crucial in determining magnetic properties, giving us a rich system to play with.

My research has always had a strong bias towards technological application - I fi nd things that are useful more satisfying. Thinking about how to use a piece of physics is also a great way to fi nd out what you really know – technology usually raises Fig. 2. A small integrated circuit built from magnetic nanowires carrying domain walls new fundamental questions. Consequently, instead of electrical conductors carrying currents. The close up of the central section shows I have founded two start-up companies a network of domain wall traps that allow a series of domain walls to be shifted backwards during the last 8 years. One sells scientifi c and forwards. Similar methods might be useful for biological detection. instrumentation to other nanotechnology researchers around the world. The other uses some of the laser scattering techniques this problem. The persistence of magnetism that I have developed while studying in the absence of any electrical current or nanostructures to help stop counterfeiting voltage is the key. If we could fi nd new and smuggling of valuable goods and ways of transferring data into magnetic documents (Fig. 1). materials, this would allow sections of the chip that are temporarily unused to be My return to the Cavendish coincides with electrically powered down for microseconds the start of two new and exciting research at a time but then brought back into service projects, which will form the basis of my instantly without data loss (Fig. 3). It may research over the next fi ve years. The seem like a small saving, but it could actually Fig. 3. An artist’s impression of a new fi rst is concerned with domain walls in make a huge reduction in the power budget design of computer memory chip, which magnetic nanowires. Magnetic domains of the chip. injects data from an electrical transistor into are regions in a ferromagnet where the atomically thin layers of magnetic material magnetisation direction is uniform; most Russell Cowburn for power-free data storage.

4 Lord’s Bridge, he demonstrated that optical interferometry is a powerful tool for future John Baldwin FRS (1931 – 2010) optical imaging. Harry van der Laan has written, “When in ESO we pushed VLT Interferometry in the late ‘80s/early ‘90s, the While Ryle drove the programme of deep work of John and his Cavendish team was surveys for cosmological purposes, John admired and served to challenge our team.” concentrated on more local aspects of radio The legacy of his achievements is the astronomy. This involved making low- involvement of the Cavendish Astrophysics frequency maps of the sky and disentangling Group in the optical-infrared interferometer from these the radio structure of our Galaxy at the Magdalena Ridge Observatory. Right and the high energy sources within it. His up to the months before he died, he was pioneering efforts were recognised in this uncovering new features of the fl uctuations message from Hugo van Woerden: “I fi rst in the refractive index of the atmosphere met John at the IAU Assembly in Dublin in at optical wavelengths which are not 1955. He gave an excellent talk about the only surprising, but which also offer new Galactic Halo, very impressive for a 24-year opportunities for optical imaging. old student. Already then, he was a great scientist.” Appointed University Demonstrator in 1957 and Assistant Director of Research in 1962, While Ryle continued the development John was promoted to a Readership in of the techniques of aperture synthesis 1981 and to Professor of Radio Astronomy to higher frequencies and higher angular in 1991, the same year in which he was resolution with outstanding success, elected to Fellowship of the Royal Society. eaders will be saddened to learn that John continued the development of radio He received numerous awards for his John Baldwin died on the morning of astronomy at low radio frequencies, over research, including the Guthrie Medal of R7 December 2010 after a short illness the years building a succession of world- the Institute of Physics, the Hopkins Prize which developed during the summer. leading survey instruments. This was a very of the Cambridge Philosophical Society major challenge because of the instability and the Jackson-Gwilt medal of the Royal In 1949, John came up to Queens’ College, of the ionosphere at low frequencies. Astronomical Society. where he graduated in Natural Sciences in This work culminated in the 6C, 7C and 1952 and then took his PhD in 1956. He 8C surveys which were the defi ning low- In addition to his distinction as a scientist, was one of the most distinguished of the frequency surveys. As George Miley has John was a brilliant teacher and supervisor ‘second generation’ of radio astronomers written, “The 38MHz 8C survey is still the of graduate students. Richard Hills, now at Cambridge and was to be at the heart of best survey below 50MHz and was an Project Scientist for the ALMA project, everything in the Radio Astronomy Group important stimulus for the next-generation wrote, “John is of course one of the main during the early years of the development low-frequency arrays, such as LOFAR.” of radio astronomy. The ‘fi rst generation’ reasons I am in Radio Astronomy - he was my Director of Studies when I fi rst came to was spear-headed by Martin Ryle whose John also pioneered spectral interferometry inspiration and strong personality led to - the Half-Mile Telescope was the fi rst Cambridge and I soon learned that trying to the opening up of radio astronomy as an interferometer to make images in the 21- think about things and do them in the way astronomical discipline - Cambridge and cm line of neutral hydrogen. Hugo van that he did was a pretty good way to go.” the UK became world-leaders in the new Woerden remarks, “In the sixties his work disciplines of high energy astrophysics and on neutral hydrogen in galaxies with the For so many of us, it will be John’s astrophysical cosmology. But Ryle could Half-Mile Telescope set the scene for our friendship, good humour and wisdom not have achieved this without the efforts of later work at Westerbork.” that we will miss beyond all else. We will an extraordinary team of brilliant colleagues miss his cheerful laughter and optimistic and graduate students (Fig. 2). John’s deep understanding of the approach. In a letter to me only one week fundamentals of interferometry and before his death, he wrote “Meanwhile the ways of eliminating the effects of my interest in life remains undimmed.” turbulence in the atmosphere were to prove We send our most sincere condolences to central to his taking up the challenges of Joyce Baldwin, in the sure knowledge that optical and infrared interferometry in the we can celebrate the life of someone who 1980s. This involved a variety of different undoubtedly changed all our lives for the approaches. From aperture masks on large better. optical telescopes to the development of the COAST optical interferometer at Malcolm Longair

Fig. 2. The Radio Astronomy Group in the early 1950s. John Baldwin is second from the left in the back row. Peter Scheuer is fi fth from the left in the back row. In the central row, from the left, are Francis Graham Smith, Martin Ryle and Antony Hewish. In the front row, second from the left is John Shakeshaft and far right Bruce Elsmore. Fig. 3. The COAST optical interferometer at the Lord’s Bridge Observatory.

5 Fig. 1

Higgs Bosons Provide Bridges to Hidden Worlds

e are Two obvious questions arise. First, why The Large Hadron Collider (LHC) at CERN accustomed should we believe that there is more to the is one of the bright lights that could Wto thinking of basic building blocks of the natural world illuminate these hidden worlds of particles physics as a discipline than what is manifested by the makeup that have nothing to do with our bodies. In that gives no special of our own bodies at the most elementary particular, the simplicity of the scalar Higgs attention to things level, and second how could we discover boson, whose profi le and characteristics are human. Yet, even such new things if they really exist? completely invariant to any special relativistic particle physics, perhaps transformation - it looks the same under the science most removed from everyday Regarding the fi rst question, there is no rotations and shifts in velocity - make it experience, is a powerful example of how known reason why the completeness of our especially sensitive to these new worlds. human-centric our past discoveries have catalogue of elementary particles should been. consist of everything that is ‘within us’. The The Higgs boson has been feted as existence of dark matter and dark energy, as the provider of mass for all elementary Consider all the known elementary particles. compellingly demonstrated by astrophysical particles, and therein lies its central fame The up and down quarks combine to make and cosmological experiments, suggests that and importance. In addition to this trait, protons and neutrons. Group the protons however, a simple connection can be made there is more out there than the particles we and neutrons together and add another between the Higgs boson of our world and know about from studies of the material we elementary particle to the mix - the electrons scalar bosons of hidden worlds, providing are made of. - and we get atoms. These atoms combine a bridge between them (Fig. 1). This is to make hydrogen, oxygen, carbon and what Frank Wilczek has recently dubbed Dark matter particles turn out to be just other elements, which in turn make cells, the ‘Higgs portal’. The reason for this very hair, lungs and feet. In short, our studies one example of the vast possibilities effective bridge between the two worlds of quarks and electrons are about human of particles and interactions that have is due to the all-pervasive nature of the beings at the most fundamental level. nothing to do with our bodies. There can Higgs boson. It is said to have a ‘vacuum be particles that pop out of the vacuum expectation value’ which means that, unlike We know there are more elementary only ever so briefl y when enough energy is all other particle fi elds we know, it has a particles than this - the gluons, the photon, concentrated at an interaction point, but non-zero value everywhere. and the W and Z bosons. These are, have no relic cosmological signifi cance. however, just the force carriers between Some approaches to building models of the Why would a fi nite vacuum expectation the charged particles in our bodies. There particle physics world through string theory, value of the Higgs boson make it an ideal are even more elementary particles beyond for example, predict thousands of particles bridge between the Standard Model and the these force carriers, the muons, tau leptons, of these kinds, of which maybe only one or hidden world? The reason is that we expect charm quark, top quark, and so on. It none could have suffi cient abundance to other fi elds in the hidden worlds to have turns out, however, that these particles are be detected in the future by specifi c dark vacuum expectation values, just like our merely copies of electrons and up and down matter experiments. Therefore, we must ask Higgs boson. Vacuum expectation values quarks, only their masses are much greater. what other avenues to discovery are there? can serve as a gluing agent to join

6 fi elds together and make them mix. That is expected to be the case when the vacuum Athena SWAN Silver and IoP Juno expectation value of our Higgs boson meets the vacuum expectation values of other Champion Success fi elds. Once glued together, the bridge is complete and particles of different worlds his summer the Cavendish Laboratory The Laboratory believes that its working can interact with each other across it. became the fi rst department in the practices are by no means perfect; there is TUniversity to receive an Athena SWAN still a long way to go in order to achieve a The LHC is expected to be the fi rst collider Silver award and only the second physics more gender-balanced representation in the in history to be able to create and measure department in the UK (the fi rst was Imperial Department. These awards have however the properties of the Higgs boson (Fig. 2), College London) to receive both the Athena provided us with a concrete foundation and therefore, by illuminating this bridge, award and become an Institute of Physics upon which to build activities, particularly we may be on the brink of discovering (IoP) Juno Champion. The Athena SWAN in the areas of career advice, mentoring, these new worlds. They would show up and IoP Juno schemes recognise excellence recruitment and promotion of female in experiments at the LHC as exotic decay in Science, Engineering and Technology physicists at all levels. The Department modes of the Higgs boson. For example, (SET) employment in higher education and also expects to spread the word and once the Higgs bosons are produced, the commitment of university departments help the School of Physical Sciences and instead of decaying into two b quarks or W to the advancement and promotion of the other University departments to increase bosons, which is what they would normally careers of women in science. awareness and support for women in SET. do, they could follow their bridges into a hidden world and decay into something In recent years, the Cavendish Laboratory Our sights are now on the Athena SWAN else. They might decay into pure hidden has made many signifi cant advances in Gold! world states, which would show up as improving the working environment for ‘invisible decays’ that can be inferred by Val Gibson all staff and, in particular, for its female careful experimentation. Or, they might academic and research staff. The Cavendish For more information, please take a look at : decay into hidden world states that may Laboratory’s Personnel Committee has transition back across the bridge in the www.athenaswan.org.uk/html/athena-swan addressed many aspects of the Department’s opposite direction, or across another bridge www.iop.org/policy/diversity/initiatives/juno/ make-up from the breakdown by gender altogether, and decay into lighter visible index.html of undergraduate exam results, the career world states that form a fi nal decay pattern progression of research staff, to the overall of, for example, four electrons. That would culture within the Department. The results be impossible for normal Higgs boson of the Committee’s investigations informed decays without bridges that go back and the Athena and Juno applications and resulted in an Action Plan for the coming years.

Amongst some of the Department’s highlights are the support and career advice at key career transition points through its Staff Review and Development scheme and its Continuing Professional Development programme. The Department also continues to develop a culture that is open and comfortable for all and has established a discussion forum for research Fig. 2 staff to address issues, such as career advice, mentoring, induction and social activities. forth to a hidden world. Such a discovery It was heartening to read some of the would inevitably lead to the hidden world Prof. Val Gibson and Mr David Peet comments in a recent research staff survey: hypothesis that could be verifi ed with collecting the Athena SWAN Silver award. further experimentation. “The culture is friendly, open, helpful and cooperative; albeit slightly competitive.” In short, our leap to the energy frontier “The Department responds to requests of the LHC and our care in measuring the e.g. picnic benches were provided when Higgs boson decays may very well lead us requested.” beyond our anthropocentric narrowness of view into vast new territories of hidden For me, the Athena and Juno ethos is worlds. And that would only be the about the “Small changes which make big beginning. differences”. For example, several years ago, on returning from maternity leave, a female James Wells lecturer was asked to give a new lecture course. She did so with all the energy and Fig. 1. A metaphor for the role of the Higgs enthusiasm that she could muster. Half- boson in acting as a bridge to hidden worlds way through the course, she was admitted of particle physics, not yet accessible to to hospital, nearly ending her career. The experiment, but which may well be opened up by experiments at the LHC. Department now has a policy that female academics returning from maternity leave Fig. 2.: A simulation of the decay of a are relieved from lecturing in the fi rst term Higgs boson decaying into four muons in following return and are not assigned a Prof. Val Gibson receiving the IoP Juno the ATLAS detector of the Large Hadron new lecture course in the fi rst year… a small Champion certifi cate from Dame Jocelyn Bell Collider. change that can make a big difference. Burnell.

7 From the Hubble to the James Webb Space Telescope

010 marked the 20th Anniversary of most distant known galaxies were relatively subsequently carbon and oxygen have the Hubble Space Telescope (HST) nearby, and fl uctuations in the Cosmic been found in its atmosphere. Water 2in space and there were numerous Microwave Background Radiation had not and methane have been detected in the celebrations of what has unquestionably been detected. We had not found evidence atmosphere of the exoplanet HD 189733b. been one of the most dramatically successful for dark energy or cold dark matter. When This planet is too hot to support life as we space science missions ever carried out. I we compare what we said we would know it, but the technique shows how was involved with the HST programme from observe with the HST in 1977 with what has organic molecules can be detected in extra- the time the project was approved in 1977 actually been achieved, it has far exceeded solar planetary atmospheres. as a member of the Science Working Group. our most optimistic expectations and made Now in 2010, I am a member of the Science major contributions to the great revolutions In the deepest images taken by the HST in Advisory Committee for its successor, of modern astrophysics and cosmology. a region known as the Hubble Ultra-Deep the James Webb Space Telescope. It is Field, the Universe of galaxies is observed worthwhile refl ecting on the success of the For example, in the Orion Nebula, the as it was when the Universe was only about HST and the issues that have faced both the region of formation of massive stars closest 5% of its present age. This image is very HST and JWST – history is repeating itself. to the Earth, dusty proto-planetary discs different from that observed at the present were discovered by the silhouettes they day (Figure bottom-left). The galaxies are It is salutary to remember that in 1977, we cast on the bright nebula. The atmosphere much bluer, more irregular and smaller were unaware of the existence of extra- of the extra-solar planet associated with than galaxies are today. This is compelling evidence that we are observing galaxies in solar planets and proto-planetary discs, the star HD209458 has been detected and the process of assembly, as expected in the favoured cosmological models which include Einstein’s famous cosmological constant. In addition supernova explosions of a very standard type, the Type 1A supernovae, have been observed to such large redshifts that the acceleration of the Universe under the infl uence of the cosmological constant has been convincingly measured.

The HST was planned to be serviced by the Space Shuttle and four refurbishment missions have been fl own. The fi rst mission had the key role of providing correction optics for the primary mirror, which had been polished to the wrong shape. Subsequent missions enabled failing batteries, gyroscopes and fi ne-guidance sensors to be replaced. In addition, much more powerful cameras and spectrographs replaced the initial instrument complement. The Advanced Camera for Surveys (ACS) provided much wider fi eld images with greater sensitivity than the original Wide Field Cameras and resulted in spectacular images, such as that of the Carina Nebula and its environment (Figure top-left)).

8 The last servicing mission was a virtuoso act requires the use of cryogens to reduce the of engineering and technology, the highlight infrared background within the instruments. being the replacement by the astronauts The nominal lifetime of the JWST mission is The Lloyd’s Register in orbit of electronic boxes buried deep in therefore only 5 years. Educational Trust the telescope which involved removing 107 tiny screws, replacing the failed electronics At the moment, the project is being supports students and not losing any of the screws. The HST thoroughly reviewed because of cost is now in excellent order for the foreseeable overruns, not unlike the situation in 1983 in Scientifi c future, that is, until the JWST replaces it when the HST programme almost ran (Figure below). out of money. The good news is that the Computing project, although the most complex space telescope ever constructed, is in excellent The JWST is named after James Webb, the he University has recently received a technical shape. The less good news is that Administrator of NASA who from February generous donation from The Lloyd’s the launch is likely to be delayed beyond 1961 to October 1968 directed the Apollo Register Educational Trust (LRET) 2014. We must hope that the funding T programme which resulted in the manned for the provision of fees-only awards to problems can be solved. With a sensitivity Moon landings. The telescope will be a students admitted to three MPhils, one about 100 times greater than that of the segmented 6.5-metre telescope optimised of which is based in the new Centre for HST, the JWST represents a further huge for observations at 1-3 m and longer Scientifi c Computing that was described leap in astronomical capability and will result wavelengths. The reason for this choice in the last issue of CavMag. Awards have in the types of breakthrough we have been is that the two key astrophysical areas been made to Lizzy Johnstone and Oliver fortunate enough to have witnessed with described above, star formation and the Strickson who started their graduate study the HST. origin of galaxies, are best studied in the with Nikos Nikiforakis in October 2010. infrared waveband for different reasons. Lizzy is working on numerical simulations Star formation involves the study of cool Malcolm Longair of two-phase reactive fl ows and Oliver on the determination of equations of state by means of atomistic modeling.

The LRET is an independent charity that was established in 2004. Its principal purpose is to support advances in transportation, science, engineering and technology education, training and research worldwide for the benefi t of all. It also funds work that enhances the safety of life and property at sea, on land and in the air. The Department is extremely grateful to the LRET, and especially its Director Mr Michael Franklin for its support of this new initiative.

regions in the Universe that emit most of Top-left: The area in the vicinity of the their energy in the near and far infrared Carina Nebula in the Large Magellanic wavebands. The galaxies we need to Cloud. This is a region of recent intense observe to understand their initial assembly star formation. This is one of the most are at such large distances that their light is remarkable images obtained by the HST redshifted from the optical to the infrared with the ACS camera, showing `elephant’s wavebands. trunk’ dark regions which are the birthplace of stars (Courtesy of NASA, ESA and the There are also important differences in the Space Telescope Science Insitute). deployment of the telescope. Unlike the Bottom-left: The Hubble Ultra Deep Field HST, which was placed in low Earth orbit (Courtesy of NASA, ESA and the Space and serviceable by the Space Shuttle, the Telescope Science Insitute). Lizzy Johnstone and Oliver Strickson JWST will be located at the L2 Lagrangian point 1.5 million kilometres from the Earth Above: The 6.5 metre James Webb Space in the opposite direction to the Sun. The Telescope, the successor to the Hubble Planck and Herschel satellites of ESA are Space Telescope (Courtesy of NASA and already in orbit at L2. Satellites at L2 cannot ESA). The sun-shield below the telescope is be serviced. Furthermore, the observatory the size of a tennis court.

9 New Workshop Course for Developing the Cavendish Graduate Students Development Plan

hat makes a good experimental scientist? The obvious e are very pleased to let you know that the most recent answer is that they must be able to design and use very version of our plans for the future development of the Wsophisticated equipment and instruments. But success WCavendish Laboratory have been approved by the School can be increased if the scientist knows something about the design of Physical Sciences and are now part of the offi cial portfolio of and manufacturing processes. Regular readers of CavMag will projects that are being supported by the Cambridge University know that the Laboratory has invested over £1M in refurbishing Development Offi ce (CUDO). Our colleagues at CUDO have been and re-equipping the mechanical workshops in recent years. Now, very helpful in promoting our proposals and giving us guidance under the excellent leadership of Peter Norman and Nigel Palfrey, about the presentation of the portfolio. the Student Workshop has received a major facelift. Three new lathes, along with four mills and associated tooling have been As we emphasised in CavMag2, the special development edition, installed in part of the former Mott workshop to provide a facility the word ‘Development’ means many things, from studentships that postgraduate students can use to make items of equipment. and start-up funds for new projects to major initiatives for the large In addition, and perhaps more importantly, they are trained in scale redevelopment of the Laboratory. The portfolio of approved the basics of mechanical instrument design and manufacture. In projects is now available on our web-site at: www.phy.cam.ac.uk/ consultation with Bill Allison, Nigel has put together a training development as a pdf fi le entitled The Cavendish Development course for postgraduate students introducing them to the concepts Portfolio. We hope you will enjoy learning more about our vision and techniques of mechanical workshop practice. Over the past for the future. term, two such courses have run and the photographs show the successful students and their work. The feedback has been At the same time, we have simplifi ed the procedure for making gifts overwhelmingly positive: one student wrote ‘Walking back to to the Development Programme. If you wish to make a donation, the offi ce was like going along the hall of fame as the different simply go to www.phy.cam.ac.uk/development and then click researchers admired our work! We all enjoyed ourselves and are on University of Cambridge Development Offi ce’s secure site. happy to have learnt all these new skills.’ Alongside the practical This takes you to a page that explains the various ways in which course, similar provision is being made to provide training in basic donations can be made. Then click on donate to the Cavendish design skills using AutoCAD. Laboratory Development Programme and that takes you to the Give Online page for Physics. There are three options, (i) an un- earmarked gift to physics, (ii) the Graduate student support fund and (iii) Outreach and young people. The value of the gift can be enhanced by using the Gift Aid procedure. The physics web-page for online giving looks like the following:

From left to right: Lars Hermann (nanophotonics), Martin Blood- Forsyth (surface dynamics). Joshua Barnes (AMOP) and Igor Gotlibovych (AMOP) on the fi rst fi rst graduate student workshop training course.

The various projects outlined in thehe CavendishCavendish DeDevelopmentvelopment Portfolio span the complete range of activity within the Laboratory and are presented in order of increasing cost. But, it must be emphasised that gifts and benefactions at all levels are of enormous Martin Blood-Forsyth with the product of the workshop training value to the Department. We will be most grateful for your support, project. Each student built their own version of this drive mechanism. at whatever level.

10 Cavendish News

Two signifi cant We welcome the following new appointments to the Assistant Staff: retirements occurred in the High Energy Mariusz Naguszewski, Chief Cryogenics Technician and Deputy Physics Group, Bryan Manager of Cryogenic facilities. Webber (left) and Stephen Topliss, Electronics Technician in Atomic,Molecular and Jan White. We wish Optical Physics. them long and happy ‘retirements’. Julie Kite, Personal Assistant to Russell Cowburn.

Felicity Footer, Group Administrator High Energy Physics (internal We congratulate promotion). Michael Pepper Emily Heavens, Group Administrator Microelectronics. on the award of the Institute of James Hope. Apprentice, Mechanical Workshops. Physics Business and Innovation Medal Jeremy Lewis, Administrative Assistant, Graduate Students Offi ce 2010. The following have won distinguished research fellowships to be held in the Department:

Stefan Ask, STFC Advanced Fellowship, High Energy Physics We congratulate Andy Parker and (Experimental) Group. James Wells on David Ritchie have his appointment been reappointed Mark Buitelaar, Royal Society Dorothy Hodgkin Fellowship, to a lectureship in Deputy Heads of Semiconductor Physics. Theoretical High Department with Energy Physics. He responsibilities Alexei Chepelianski, Oppenheimer Research Fellowship, describes his work in for Finance Optoelectronics. an article in this issue and Teaching Jesper Levinson, Marie Curie Fellowship, Theory of Condensed of CavMag. respectively. Matter Group.

If you would like to discuss how you might contribute to the The Scott Lectures, on 7, 9 and 11 Cavendish’s Development Programme, please contact either March 2011, will be delivered by Professor Malcolm Longair ([email protected]) or Professor Claude Cohen-Tanoudji of the Peter Littlewood ([email protected]), who will be very École Normale Supérieure, Paris. pleased to talk to you confi dentially. Further information He won the 1997 Nobel Prize in about how donations may be made to the Cavendish’s Physics for research into methods Development Programme can be found at: of laser cooling and trapping www.phy.cam.ac.uk/development atoms.

Contacts

The Cavendish Laboratory Head of Department JJ Thomson Avenue Professor Peter Littlewood Cambridge Tel: 01223 337429 CB3 0HE E-mail: [email protected]

Tel: +44(0) 1223 337200 Director of Development Fax: +44(0) 1223 363263 Professor Malcolm Longair E-mail: [email protected] Tel: 01223 765953 www.phy.cam.ac.uk Email: [email protected]

3 Senior Physics Challenge, Physics at Work & the Science Festival 2011

Senior Physics Challenge the 2010 award went to the Cavendish’s Lecture Theatre of the Cavendish and will Fracture and Shock Physics group. be given by Professor Sir Richard Friend The Senior Physics Challenge Summer on Greener Solar Cells. School took place at the end of June Bookings for the 2011 exhibition will open 2010 completing its fourth successful towards the end of May 2011. Interested Every year the number of visitors to year of operation. We received nearly 300 teachers should refer to our website for this event increases and so, in order to applications from the highest calibre Year regular updates at www-outreach.phy. help visitors plan their day and to avoid 12 (AS-level) students to participate in this cam.ac.uk/physics_at_work. The exhibition disappointment, we are planning a physics access and admissions initiative. is targeted at 14 -16 year olds with some more structured programme for 2011. From these 300, co-director Anson schools bringing their gifted and talented Two 30 – 45 minute lectures will run Cheung and I selected 66 students, each year 9 students and others bringing year in parallel from 1:15pm for ages 5+, from different schools located all over the 12 students who are considering potential 8+, 12+ and 14 to adult, including the United Kingdom. Hosted by several of the careers in physics. Schools are welcome keynote lecture and lectures on astronomy Cambridge colleges, students were treated to bring as many students as they can, and experimental physics for all ages to the full Cambridge experience including so long as the teacher to student ratio is presented by myself and ‘Naked Scientist’ attending lectures on kinematics and special about 15. On arrival at the Cavendish, Dave Ansell. To guarantee a seat at these relativity and practical laboratory classes each school party will be split into groups lectures you will be able to pre-book on on dynamics and optics. The students of approximately 15 students with 1 our website www.cta.phy.cam.ac.uk/ also attended admissions talks and had accompanying teacher. Map in hand each outreach/Science_Week/booking.php for the chance to discuss physics and socialise group is then led to their fi rst exhibit to a maximum of 3 lectures. Some seats with like-minded students of a similar follow their own tailored route around the age. Students responses indicate that we Cavendish. Schools travel from all over (1/4) will kept open for people turning are indeed achieving our aims, comments London and the South East to attend this up on the day but in this case availability included, “I didn’t realise how much maths event. Approximately 400 FREE places are cannot be guaranteed. The programme is was involved”, “I enjoyed the challenge available for each half day session. shown at the foot of the page. of hard, but not impossible, problems and solving for them for the fi rst time” and Science Festival 2011 In addition to the lectures and talks “meeting like-minded people was very there will be many hands-on science rewarding”. The Cavendish Laboratory will once again experiments and a planetarium. We also be opening its doors to the public on 26th hope that some of our sci-fi guests will Preparations for the 2011 Senior Physics March 2011 as part of the Cambridge also be joining us once again. Regular Challenge are already underway. Student Science Festival. The event will run updates can be found on our outreach applications are initiated by teacher from 1 – 5pm with lectures, hands-on website at www-outreach.phy.cam.ac.uk. recommendation and any interested teacher demonstrations and make and do activities may register online to receive updates and available throughout this time. The keynote notifi cation of the next application round. lecture will begin at 1:15pm in the Small Lisa Jardine-Wright To fi nd out more please visit our website www-spc.phy.cam.ac.uk. ‘Meet the Physicist’ Talks Physics at Work 2010 Keynote Lecture: Greener Solar Cells Adult, 14+ Small Lecture Theatre (150 seats) Professor Sir Richard Friend Bookings for the 26th annual Physics at Work 1:15 – 2pm Crisp Packet Fireworks exhibition reached record numbers this 12+ Pippard Lecture Theatre (400 seats) year – we welcomed nearly 2200 students David Ansell through the doors of the Cavendish. This Light the Messenger 8+ Small Lecture Theatre (150 seats) Dr Lisa Jardine-Wright unique exhibition ran for three days from 2:30 – 21st until 23rd September, with two sessions 3pm: Crisp Packet Fireworks 5+ Pippard Lecture Theatre (400 seats) each day at 9am and 1pm. The school David Ansell groups saw six different exhibits selected Cavendish Science by the organisers, to include both internal Adult, 14+ Small Lecture Theatre (150 seats) Lisa Jardine-Wright and industrial exhibitors, showing the many 3:30 – 4:15pm varied ways in which physics is used in the Crisp Packet Fireworks 12+ Pippard Lecture Theatre (400 seats) real world. We were delighted to welcome David Ansell 24 seasoned and new exhibitors to the Introduction to Astronomy 5+ Small Lecture Theatre (150 seats) event this year. Lisa Jardine-Wright 4:30 – 5pm Crisp Packet Fireworks Each year we ask students and teachers to 5+ Pippard Lecture Theatre (400 seats) David Ansell vote for their favourite exhibit and this year

12