109

Winter 2004

Number 109

SCUBA - 2 - Moving Objects - pg 8 - Dr. Phil is a "Prize" - pg 9 Page 2

- Fall Convocation - pg 10 - Undergraduate Physics Conference - pg 12 Phys 13 News / Winter 2004

Canadian Foundation for Innovation Grants

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A joint Canada-UK SCUBA-2 camera (SCUBA: submillimetre common user bolometer array) to be located on the James Clark Maxwell Telescope, in Hawaii, to produce images of the deep universe using radio waves.

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The Canadian access-fee to the Atacama Large Millimetre Array (ALMA) Telescope – a major international construction to be based in Chile, which will be the foremost land-based instrument over the next 20 years.

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A beamline at the most advanced neutron spallation installation in the world, at Oak Ridge, Tennessee in the USA, to secure the leadership of Canadian researchers in using neutrons to look at engineering materials.

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The KOPIO Project – a new experiment in particle physics to explore the origin of matter. The project is a major new international initiative led by a team of internationally renowned Canadian scientists in Canada, and involves 63 scientists in six countries.

by G. Scholz Dept. of Physics, Universiy of Waterloo Dr. David W. Strangway, President and CEO of the Canada Foundation for Innovation (CFI) announced the names of nine large-scale research infrastructure projects aimed at promoting Canada's position in the areas of marine and environmental sciences, infectious diseases, astronomy, light sources, and particle physics. All projects were selected following a national competition and will be funded by the CFI from two special $100 million allocations. The projects are divided into two categories: 1) The International Joint Ventures Fund is aimed at creating infrastructure in Canada that would showcase internationally outstanding research being undertaken in Canada, and to enable Canadian researchers to collaborate with the best scientists in the world. Three projects were selected under the International Venture Fund: •

A research icebreaker to study the changing Arctic Ocean and global climate change issues.

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A highly innovative 5-beam advanced laser – capable of spanning a very wide range of wavelengths – a fundamental tool to transform the Canadian research and training environment in disciplines such as physics, chemistry, and biotechnology.

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A major new International Facility for Underground Science to transform Ontario’s internationally renowned Sudbury Neutrino Observatory (SNO) from a large-scale experiment to a world-class facility and scientific destination.

2) The International Access Fund is designed to offer Canadian researchers access to world-class research collaborations and facilities located elsewhere in the world which will allow them to collaborate with the best researchers in many subject areas that are important for Canadians. Six projects were selected under the International Access Fund: •

The Neptune Program to strengthen Canada’s leadership in research in the deep ocean.

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The Canada-Kenya research laboratory to provide outstanding researchers in Canada – and their international collaborating partners in Nairobi, Oxford and Washington – with a state-of-the-art facility for research on highly infectious diseases such as AIDS and hemorrhagic fever.

Phys 13 News / Winter 2004

The Physics Department at the University of Waterloo is proud to be hosting “SCUBA-2”, which is described in more detail below. We hope to feature other projects in future issues of Phys 13 news.

SCUBA-2: A Submillimetre Camera for Astronomy by Mike Fich Dept. of Physics, University of Waterloo Canadian astronomers are at the centre of major research efforts at submillimetre wavelengths. A large part of the reason for Canadian successes in this area is Canada's contribution to projects providing absolutely the best instrumentation available anywhere for submillimetre astronomy. The most successful submillimetre instrument in the world is SCUBA which is, in part, managed by Canadian astronomers. This article presents a summary of the SCUBA success story and of a new instrument, SCUBA2, now being fabricated within Canada and at the institutions of its international partners. Astronomy at Submillimetre Wavelengths When we look up at the sky at night we see stars everywhere. When we look at a galaxy it is the stars in that galaxy that are visible to us. Fig. 1 shows the Andromeda galaxy, a large spiral galaxy, and two other small galaxies

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that are all close to our own “Milky Way” galaxy. Although we cannot distinguish individual stars in these galaxies all of the light we see originates from stars. Note also the many individual bright points spread over the entire picture in Fig. 1. Virtually all of these are stars in our Galaxy. We are inside our Galaxy and we look through some part of our Galaxy no matter which direction we choose when we observe other places in the Universe.

die they expel much of their matter back into the ISM. Thus it is the ISM that provides us with much information on the births and deaths of stars. However, virtually all of the light emitted by the ISM is at longer wavelengths. Unfortunately (for astronomers) the Earth’s atmosphere is not transparent at all wavelengths. Visible light and a wide range of radio waves are able to reach the surface of the Earth. A small part of the ultraviolet and near-infrared parts of the spectrum can pass through the atmosphere too. (The “cut-off” in the ultraviolet is determined by the ozone layer in the Earth’s atmosphere.) At submillimetre wavelengths there are “windows”, narrow in wavelength range, where light is only partially absorbed by the atmosphere. At high altitudes the transmission through the atmosphere is improved, but is critically dependent on the amount of water vapour in the air above the observing site. Submillimetre astronomers search for the highest and “driest” sites in the world for their telescopes.

Fig. 1: The Andromeda Galaxy and two small companion galaxies

Most of the light produced by stars is at visible wavelengths, the light that our eyes are evolved to detect. But there are other things besides stars in the Universe. For example, in Fig. 1 the Andromeda galaxy has dark patches encircling its centre. These are a visible sign of that galaxy’s interstellar medium (or ISM), the material between the stars. These dark patches are due to a small amount of interstellar dust (microscopic particles, solids made of many elements including especially carbon, oxygen, and silicon) mixed in with the gas that dominates the ISM. Dust typically makes up approximately one percent (by mass) of the ISM and the ISM itself has a mass of perhaps five percent of the mass contained in stars. While the dust absorbs visible light, it emits very strongly at longer wavelengths of light where our eyes can not see. Just beyond visible wavelengths, the infrared is often split into the near infrared, mid-infrared, and farinfrared. Longer in wavelength still are the various radio wavelengths, beginning with the submillimeter, then the millimeter, centimeter, decimeter, and meter wavelengths bands. Many galaxies are equally bright at visible wavelengths and at far-infrared and submillimeter wavelengths. Thus the picture of the Universe as seen in the visible, as in Fig. 1, is missing a great deal. The ISM contains the material that forms into stars, and when stars

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Fig. 2: Telescopes on the summit of Mauna Kea, Hawaii

Fig. 2 shows the summit of Mauna Kea, a dormant volcano on the island of Hawaii. At 4,000 meters (14,000 feet) the climate there is quite good for astronomy. Many telescopes are located on Mauna Kea, including those operating at visible, near-infrared, submillimetre and radio wavelengths. Visible-light telescopes there include the Keck telescopes (the largest visible-light telescopes in the world, the two identical white domes to the right of centre in Fig. 2), Gemini (a very new, very large telescope partially owned by Canada, the large silver dome to the left of the centre), the Canada-France-Hawaii telescope (the large white dome in the centre in the foreground) and Suburu, a new Japanese very large telescope (just behind and to the left of the Keck telescope domes). The largest submillimeter telescope in the world is the James Clerk Maxwell Telescope (JCMT) which is also on Mauna Kea. It is seen in Fig. 2 far in the background just

Phys 13 News / Winter 2004

to left of the centre. A closeup view of the JCMT is shown in Fig. 3. For a scale size in the picture note the two cars in the garage at the left of the building. The JCMT is jointly owned and operated by the United Kingdom, Canada and the Netherlands.

Fig. 3: James Clerk Maxwell Telescope

theoretical predictions. Some of these and other SCUBA discoveries are highlighted in the sections below. Disks around Stars The study of debris disks of cold dust around nearby main sequence stars can give vital clues to the planetary formation process. This dust is thought to arise from material left over from the formation of planets. Not only do such images give us an effective ‘time series’ showing how our early planetary system evolved from a circumstellar disk, but perturbations, seen as clumps and cavities in the observed image, have the potential for actually pinpointing the locations of young planets. In Fig. 4, a SCUBA image of a nearby system is shown beside a computer model. In the numerical simulation of the ε Eridani dust disk (shown at right of Fig. 4) an inner planet (known to exist from radial velocity searches) has cleared the central region (orbit shown as solid circle), whilst an outer planet (dotted circle) causes perturbations in the dust disk. The position of this putative planet can be estimated (large white dot). ε Eridani observation

Numerical simulation

The JCMT began operation in 1987 with a sensitive single channel bolometer (borrowed from another telescope on Mauna Kea), the best detector available, that measured the brightness of one spot on the sky – a single pixel. To make an image required such a laborious process of scanning this one pixel across the sky that only a few modestly-sized images were ever made. A first generation of “Common User” instruments was built over the next ten years. The most successful of these instruments was SCUBA, the Submillimetre Common User Bolometer Array which was delivered to the JCMT in late 1996. This instrument consisted of two arrays, simultaneously imaging at two wavelengths (450 and 850 microns), with a total of 131 pixels. Its imaging speed is approximately 5,000 times greater than the previous single channel bolometer. Exciting scientific results came from SCUBA almost immediately. Astronomers used SCUBA to find, for the first time, galaxies forming at the edge of the Universe in the distant past. SCUBA played a leading role in showing that the physical processes that select the masses of stars have already done so while the protostellar clouds are cold and large, before these clouds begin their gravitational collapse to form stars. Polarimetry (the measurement of the polarization of light) with SCUBA showed an amazing correlation between interstellar magnetic field geometries and the structure of interstellar clouds. Observations with SCUBA have found the dust leftover from the process of forming stars and planets in nearby solar systems, finally confirming established

Phys 13 News / Winter 2004

Fig. 4: (Left): SCUBA 850 micron observation of the faint dust ring surrounding ε Eridani (Greaves et al. 1998). (Right): numerical simulation of dust trapped in mean motion resonances with a putative planet (Liou, Greaves & Holland 2002, in prep).

The Centre of our Galaxy A recently produced very large scale SCUBA image of the plane of our Milky Way galaxy in the vicinity of the Galactic Centre is shown in Fig. 5. This superb image (made by a team of 14 astronomers from 5 countries including Canada) shows a great deal of structure and will be the object of extensive further study. The observations required to produce this image consumed many days of time using the JCMT, and yet this represents approximately 0.01 percent of the plane of our Galaxy, and the plane of the Galaxy is only a small fraction of the overall area in the sky. While SCUBA is currently the most powerful instrument of its kind, it is still limited in what it can produce. There is a large international effort underway to image the entire Galactic Plane at other wavelengths, but with current instrumentation this has not been possible at submillimetre wavelengths.

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Fig. 5: The Plane of our Galaxy towards the Galactic Centre (Sagittarius A)

Star Formation

Polarimetry

With SCUBA it is possible to produce moderatearea (fraction of a square-degree) fields of nearby molecular clouds (such as the 850 micron image of Orion shown below in Fig. 6). A great deal of structure is found within these maps on all scales, from individual pointsources and moderately resolved clumps of prenatal dust and gas, through clusters of clumped sources, to largescale filaments, with and without internal fragmentation. These SCUBA maps reveal that the molecular cloud material condenses into individual clumps, with a distribution in masses similar to that of the initial stellar mass spectrum. Yet only some regions of the cloud are able to form these clumps, and the clumps that form appear stable to internal gravitational collapse. On larger scales, details of the filamentary structure within molecular clouds provide evidence for the presence of ordered magnetic fields, which may be dynamically important.

The study of polarized radiation is the primary means of investigating the geometry of magnetic fields within astronomical sources. These fields are prevalent throughout galaxies, from the largest scales to the small cores that are collapsing to form stars within molecular clouds. Understanding the geometry of these fields, both at a global and a detailed level, is crucial to our understanding of star formation processes and the physics of molecular clouds. Polarimetric maps of dense filamentary clouds in Orion obtained with SCUBA have shown that the magnetic field structure (the many small straight lines in Fig. 7) can be explained with a theoretical model of filamentary clouds with a helical magnetic field.

Fig. 6: Orion at 850 microns

Fig.7: Polarization observations of Orion's Molecular Cloud

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Recently, it has been possible to combine three observational techniques to obtain a 3-D map of the field configuration in the M17 molecular cloud. The strength of the magnetic field along the line of sight is provided by Zeeman measurements, polarimetric measurements give the orientation of the field in the plane of the sky, and the ion-to-neutral molecular line width ratio determines the angle between the magnetic field and the line of sight. SCUBA-2 will provide essential measurements for studying magnetic fields in 3-D in other regions.

Phys 13 News / Winter 2004

Cosmology: The Formation of Galaxies Observing in the submillimetre region offers equal sensitivity to dusty, star-forming galaxies over an enormous range in redshift (1 < z < 10), and hence access to the Universe at epochs from about half way back to only 5% of its present age. Current SCUBA surveys have uncovered about 100 submillimetre galaxies, which have changed our view of early star formation. Follow-up of the current samples suggests that the brightest sources represent the formation of the massive elliptical galaxies, which contain about half of the massive star formation occurring at these early times. SCUBA-2 will allow us to probe more normal galaxies as well. The population revealed in the submillimetre region has proven to be extremely faint at other wavelengths. (see Fig. 8 for an illustration of this!) Cosmology: The Formation of the First Stars We know from studies of the Cosmic Microwave Background that the Universe began in a very uniform smooth state, with few structures. At some point the “Cosmic Dark Ages” came to an end through the birth of the first stars within primordial galaxies. Nuclear energy was converted to light in stellar interiors, and had important heating and ionization effects on the surrounding medium. Exactly how this process began and evolved is currently one of the greatest cosmological puzzles. Recent work in the submillimetre waveband has shown that luminous infrared galaxies evolve more strongly than their more normal optically-bright counterparts. It has also become clear that luminous obscured galaxies at high redshift contribute a substantial fraction (arguably the majority) of the total emitted radiation in the Universe. Roughly half of all the stars that have presently formed, probably formed in highly obscured systems. To trace the star-formation history of various galaxy types over cosmic history with precision requires much larger samples

than currently available. SCUBA-2 will for the first time allow us to trace this cosmic star-formation history.

SCUBA-2 The SCUBA-2 project is a unique opportunity to exploit emerging new technology to produce the world’s most advanced camera for astronomical research in the poorly explored submillimetre region of the spectrum. SCUBA-2 will replace the original SCUBA camera in mid-2006. SCUBA-2 is being built by a large team of researchers with members from various universities and research institutions in the UK and Canada, with the detectors being fabricated under contract by the US National Institute of Standards and Technology (NIST). The lead UK institution in the project is the Astronomy Technology Centre (UK ATC) at the Royal Observatory, Edinburgh, and the lead Canadian institution is the University of Waterloo. The Canadian SCUBA-2 consortium consists of eight Canadian universities (in addition to University of Waterloo these are: Saint Mary’s University, Université Laval, Université de Montreal, University of Lethbridge, University of Calgary, University of British Columbia, and University of Victoria). The international SCUBA-2 team includes the Canadian Consortium plus a number of other world-renowned groups, including the group at NIST in Boulder, Colorado, the Astronomy Instrumentation Group at the University of Cardiff, and the Scottish Microelectronics Centre at the University of Edinburgh. To achieve the scientific potential of SCUBA-2, with a mapping speed that is at least 100 times that of SCUBA (this is the design goal), SCUBA-2 will have focal planes operating at two wavelengths simultaneously (450 and 850ìm) that utilize most of the usable field of view of the telescope. This requires ~10,000 pixels - a pixel count

Deep-etched trench (10 µm)

1.135 mm

Implanted Absorber

TES Quarter-wave Si Brick

Fig. 8: (l) a long exposure of a small part of the sky with the Hubble Space Telescope. Almost every object in this picture is a galaxy. (r) A “deep” exposure of the same part of the sky with SCUBA. Everything shown is a source of submillimetre light (there is no “noise” in the image). Essentially every object seen in the submillimetre image is not detected in the visible image.

Phys 13 News / Winter 2004

SQUID MUX Backplan

Indium bump bonds Nitride membrane (0.5 µm)

Fig. 9: A single SCUBA-2 pixel. Submillimetre light enters the instrument from above and is absorbed, heating up the absorber. The TES “measures” the temperature increase and the temperature is read out by the SQUID MUX (multiplexer). cont'd on pg 16

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Moving Objects by Walt Duley Dept. of Physics, University of Waterloo The visual detection of motion has perplexed scientists from the earliest days of research into the mechanisms of vision. An ability to detect motion, of course, has obvious evolutionary advantages and so it is not surprising that this capability has been “hard-wired” into the eye. This hardware takes the form of special detectors: rods at the outside of the retina that are sensitive only to motion. Motion of an image over this area on the retina has been programmed to invoke a response in which the eye rotates to acquire an accurate image of the moving object. This acquisition then permits the object to be identified and assessed as a potential threat. It is important that the eye rotate because the detectors at the edge of the retina respond only to a change in illumination. Indeed, one cannot see an object in peripheral vision unless it is moving. Motion of an object can also be detected by following it with the eye while retaining a focus. In this case, the background to the object may also move across the retina causing a perception of motion, but it has been shown in a large number of well-controlled experiments that motion can still be detected even in the absence of a background reference. This suggests that there are two distinct systems to acquire and measure motion, both hard-wired into the brain. One of these is the response of a stationary eye to the motion of an image across the retina. The other would appear to consist of a bio-mechanical measurement system that records the movement of the eye and produces an output signal that the brain evaluates to detect motion and velocity. While both mechanisms are plausible, they provide only a simplistic description of the manner in which motion is detected. From common experience it is known that under certain conditions motion appears to occur even when an object is stationary. Well known is the waterfall illusion, wherein a stationary object, viewed after watching the waterfall, will appear to move in an opposite direction to the water flow. Similarly, a blinking light in a dark room will also appear to move when one stares at it. Even a stationary light will seem to move erratically in a completely darkened room or a small mark on the wall may seem to migrate in dim light. When objects do move, the eye can follow them without disorientation. We also sense no motion when the eyes turn to scan a stationary scene, even though this

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means that the image is being moved over the retina. On the other hand an after-image produced by a photographic flash will remain at the same point in the field of view as the eye is turned, so that the act of rotating the eye cannot itself introduce an element of motion into a stationary scene. These observations argue that there are at least two separate mechanisms contributing to a determination of the motion of objects in the visual field, and that both act together in acquiring and processing this information. Inhibiting or compromising one of these mechanisms can have the effect of introducing motion where none exists. The disorientation that accompanies over-indulgence in alcohol may be an example of such a compromise. Elements of motion sickness may also be related to conflicting visual and other sensorial stimuli as the motion detection and assessment system associated with vision yields different information from that provided to the brain by the inner ear. This can be experienced in driving as peripheral vision detects motion asynchronous to signals from the inner ear. Detecting and assessing motion visually involves these “hard-wired” subsystems, but it also has elements of an acquired knowledge base. This “practical” knowledge has been obtained over time through experience of how things should look in relation to their size and shape. Simulation of the overall response of the eye to motion, now done by analysts using a variety of increasingly sophisticated computer models, shows that signals from all the body’s motion sensors (head with respect to body, head with respect to world, eyes with respect to body, etc.) are referenced to this knowledge base in order to reach a decision as to the nature of the event. It is as if the brain applies a filter to visual signals to select those characteristics that are needed to invoke a physiological response. In reaching conclusions based on this filtered information, the brain is required to make a decision and it tends to pick the one that is most consistent with the information available. In effect, it is a sort of “fuzzy logic” analysis to the data available. If this leads to the conclusion that an object is moving, then it must be moving, or one must be moving in relation to it. A good example of this phenomenon is the image of a rotating spiral that, if it fills the field of view, stimulates a response that makes it feel like one is being drawn either toward the spiral or away from it. Another effect can be seen when the moon appears to move with a car when driving, but at slightly slower speed. All of these phenomena show that visual data has strong temporal as well as spatial components, and that the brain does its best in evaluating these data and coming up with a conclusion that matches its perception of reality. Fortunately, most of the time this works, but occasionally when no clear decision is possible, the brain opts for its own interpretation, a sort of mental slight of hand!

Phys 13 News / Winter 2004

Dr. Phil is a "Prize"! by Gretchen Harris Dept. of Physics, University of Waterloo At a gala awards ceremony in Ottawa on November 19, Phil Eastman was one of five winners of the 2003 Michael Smith Awards which recognize outstanding achievement in the promotion of science in Canada. These awards are sponsored by NSERC (the Natural Sciences and Engineering Research Council) and are named in honour of the late Canadian Nobel Laureate Michael Smith. Anyone who has taken the Sir Isaac Newton exam knows who Phil Eastman is and that this award is long overdue, but SIN is only a part of how his career in physics has enriched literally hundreds of thousands of lives for more than 30 years.

the people who came up to speak to him at the awards gala wanted to say how important the SIN exam was to them. One of those was Rajiv Gupta, who is currently President of the Royal Astronomical Society of Canada and was at the ceremony to accept a Michael Smith Award to the RASC. But he wanted to tell Dr. Phil how much the SIN exam and its challenges meant to him. Among the letters we received was one from Jeff Catania, once a SIN exam participant and now with the Halton District School Board; he speakes eloquently about how the challenge of the SIN exam stimulated by the joy of figuring out the answers was at least as important as doing well and possibly even winning - which he did. For him the problem solving skills developed through SIN have been important throughout his career. The SIN exam has been at least as important to physics teachers who find it valuable in honing their own skills and motivating students. Retired Grade 13 physics teacher Ted Passmore recalls that "...SIN questions ... inevitably raised the bar and allowed for interaction between them (students) and me on a level beyond that which normally occurred in class". If you have not seen the "Circus of Physics" you have missed a major treat. According to Carl Thompson, a teaching colleague from engineering at UW, "his show has been honed to perfection... after each punch line... Phil explains the science behind each result in a simple, easy to understand manner." He could hold groups of 200 or more grade 6 students in rapt attention for these demonstrations. Another colleague tells of his 87 year old mother who saw Dr. Phil spread the excitement of physics to a group of retired learners in Woodstock. Afterward she went up to him and said she had a son who taught physics - Phil remembered him and impressed her forever.

Phil Eastman has a contagious love of physics that he has shared successfully with people of all ages. As I was gathering material to support his nomination, I was amazed by the variety of people I could call on and who were thrilled to write their stories of Phil Eastman and physics. When all was collected we had too much material and had to cut it back! Most people wanted to talk about the SIN exam or the "Circus of Physics" but of course he was also editor of Phys 13 news for many years and I learned that he also co-authored a high school physics text which has been used for decades in both Canada and the United States. Phil Eastman created SIN in 1969 and since then over 150,000 high school students in more than 1000 schools have been tested and entertained by it. The combination of good, challenging problems with delightful (often Canadian-based) humour has made the SIN exam something that both students and teachers still look forward to 35 years later. Phil Eastman told me that many of

Phys 13 News / Winter 2004

Another, perhaps less well known element of Phil Eastman's contribution to physics and physics learning has been his work in the development of physics textbooks. He and David Martindale developed several books between 1987 and 1992; at the present time there are over 250,000 copies of these (in both French and English) in circulation today. His outreach included science fairs and their development. To Dawn Scheifley he "was a catalyst to interest the students and parents" as they developed science fairs at elementary schools in Waterloo region. These are only some of the stories to be told about Phil Eastman and I am sure many of you also have fond memories of Phil. Just in case any of you are interested, Dr. Phil's wife accompanied him to Ottawa and made sure he had a haircut and decent suit to wear. As the photo accompanying this article shows, he does dress up ok. Congratulations for an honour well deserved!

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UNIVERSITY OF WATERLOO EIGHTY-SEVENTH CONVOCATION OCTOBER 25, 2003

Saturday, the 25th of October, would have been a very normal day for most of us. However, for a few (11 to be exact) physics students this was one of the most important days of their lives. After four, five or even six years of very hard work at the university, these students would receive their Bachelor's, Master'ss or Doctorate Degree at the 87th Convocation Ceramonies. Some were given very special recognition for their outstanding achievements. The University of Waterloo Alumni Gold Medal: For Outstanding Performance in a Master's Program: Adrian Del Maestro Doctor of Philosophy Degree: Gautam Das - "Multiwavelength Fiber Laser" Sanjeev Seahra+ - "Physics in Higher-Dimensional Manifolds" Master of Science Degree: Andrew Chen Adrian Del Maestro+ Ryan Kerner Casey Myers

Robert Nieckarz being congratulated by Dr. Lazaridis. Robert plans to continue with graduate studies here at Waterloo.

Bachelor of Science Degree: Honours Science (Physics Minor): Michael Gomes Ian Szufnara Honours Science - Physics Babur Butter Nikki Chan Dean Gibson* Sean Jackson Aleksandar Jevtic* John Newsome Bart Piwowar Connie Sutherland† Dhruv Vagale Honours Science - Chemical Physics Robert Nieckarz *Co-operative Program † Dean's Honours List + Outstanding Achievement in Graduate Studies

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Bart Piwowar receiving a word of advice from the Provost. Bart first came to Waterloo as a high school co-op student.

Phys 13 News / Winter 2004

Adrian Del Maestro being congratulated by Chancellor Mike Lazaridis on winning the Gold Medal for his performance as a Master's student. Adrian is now pursuing Doctoral studies at Yale University.

(l to r) Sean Jackson: graduate student at Univ of Waterloo, planning to be a teacher. Connie Sutherland: graduate student in the Ph.D. program at Univ of Ottawa Aleksandar Jevtic: environmental researcher, planning to do graduate studies. Dhruv Vagale: Teaching Assistant for the Dept. of Physics, and plans to pursue graduate work in business entrepreneurship.

Phys 13 News / Winter 2004

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Canadian Undergraduate Physics Conference by:

Nathan Babcock Owen Cherry Mark Eaton Rob Helsten

Sebastien Casault Chris Cookson Mike Garrett

The 39th annual Canadian Undergraduate Physics Conference took place from October 30th to November 1st 2003 at McGill University in Montréal, Quebec. From the moment of our arrival, we were enthralled by the welcoming atmosphere of one of Canada’s oldest cities. From the historical character of the old city to the hustle and bustle of Chinatown, Montréal weaves a rich tapestry of the diverse Canadian identity.

We arrived Wednesday evening, the day before the conference commenced. After settling into our accommodations (and, of course, a quick trip to the nearest dépanneur) we made straight away to Schwartz’s Smoked Meat Restaurant. Since 1903, Schwartz’s has been a central attraction in Montréal, offering some of the most mouth-watering smoked meat you ever did taste. Honestly, it was incredible. The conference roared ahead at full steam bright and early the next morning, with an opening address given by Scott Tremaine on the long term stability of our solar system. Understanding the stability of the solar system amounts to solving an N-body problem on a time scale of many millions of years. Simulations of the present configuration of the solar system have been performed for planetary orbits over the next 100 million years, and approximate analyses have been given for longer time scales still. The conference also featured lectures delivered by a number of other keynote speakers, including Waterloo’s

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own Ray Laflamme. Professor Laflamme spoke on recent advances in Quantum Information Theory as well as some of his own work at UW’s Institute for Quantum Computing. Cecile Fradin of McMaster University gave a fascinating description of her methods for observing single macromolecules inside living cells. Peter Grutter of McGill University spoke on nanotechnology, explaining how he uses scanning tunneling microscopy to build nanoscale structures, atom by atom. The conference’s closing lecture was given by Geoffrey West, who delivered a light-hearted but thought-provoking address on the scaling laws of biological systems, ranging in size from microbes to whales.

Of course, the main focus of the conference is not the talks given by the keynote speakers, but those by the students themselves! For many undergraduate physics students, it was their first opportunity to formally present their own work and research. Each student delegate was allotted twelve minutes for his or her presentation, followed by a three-minute question period. To provide useful feedback to the speaker (and to award prizes for the very best), two judges also evaluated each talk. Four talks in four separate conference halls took place simultaneously during each fifteen-minute time slot, with a three-minute transition period in between. Choosing which talk to hear next could often be a difficult decision. This year’s first prize talk was given by Hyun Youk from the University of Toronto and was entitled, “Magnetic Trapping of Neutral Atoms Using Anti-Helmholtz Coils and Microchip Traps.” Those who attended attested the fact that it was one of the best presentations there. Another notable talk titled, “Quantum Physics: There’s Magic Everywhere” was given by William Archer of the University of Calgary. Ever the entertainer, Archer presented some of the most intriguing aspects of quantum theory in the form of a magic show, complete with tuxedo, top hat, and magic wand.

Phys 13 News / Winter 2004

Students who preferred not to give an oration also had the option to submit a poster describing their work. Three hours were allotted to poster viewing, providing ample time to peruse the wide variety of topics presented, ranging from biomagnetism to mathematical magic cubes. A particularly entertaining poster on the Slinkyä was presented by Patrick Clancy and Fraser Turner of St. Francis Xavier University. Clancy and Turner investigated spring constants and critical slinking angles of a number of commercially available slinking devices. They also measured the “slinkiness” of each device, that being the number of stairs it can slink down before it gets pooped out and stops. As all good slinky researchers know, the “slinkiness” factor is directly proportional any Slinky’s degree of “fun.”

No CUPC would be complete without a tour of the hosting university’s laboratories. Most of the tours took place in McGill’s Ernest Rutherford Physics Building. There was much too much interesting research to describe all of it in detail, but it is worth mentioning some of the highlights. At Dr. Maria Kilfoil’s Soft Condensed Matter lab, her group gave a short presentation on the use of optical tweezers to manipulate matter. Many of us also visited to Dr. Peter Grütter’s NanoScience and Scanning Probe Microscopy lab, where we saw various applications of atomic force microscopy, including their research on nanoscale transistors.

Phys 13 News / Winter 2004

On Friday evening the annual Grad Fair was held, providing a chance for the delegates to get a flavour for the graduate research opportunities available at schools from all around Canada. Each year, representatives from universities across the county set up displays describing work being done at their schools. Some institutions send professors currently looking for grad students and others send the graduate program advisors, but they’re all quite keen to endorse both their schools and their research. This year, as the Grad Fair took place on Hallowe’en, many of the school’s booths offered candy, but that wasn’t the only treat in store. At the end of the night, McGill brought in its own “Red Shift Blues,” a band composed of McGill physics profs played classic hits from such groups as the Beatles and CCR (and we’re not talking about the Canonical Commutation Relations, either!). Playing to a packed house of rowdy physicists, the show was an obvious success.

After the closing ceremonies on Saturday evening, we all had a chance sit back and relax with our newfound friends before our long train ride home. The next day we departed from Montréal happy, exhausted, and a little envious of the people who live their daily lives in exciting Montréal. The people there love their city and truly enjoy sharing what they have with visitors. Next year’s CUPC will be held at the University of Victoria in beautiful British Columbia. See you there!

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FIND THE NOBEL LAUREATES PUZZLE #1 The answer to this Phys 13 news (#108) puzzle is

Tony Anderson

"SCHRODINGER"

Erwin Schrödinger (1887 to 1961) from Austria, received the Nobel prize in physics in 1933, shared with Maurice Dirac, for the discovery of new productive forms of atomic theory.

We received correct entries from Chris Curran, Ali Reza Sharafat, Robert Bandurka, Brenda Gerein, Marc Craig, Chris Edwards, Robin Bunner, V. Srinivasan, Helen Kro and E. Dunning. The winner of our book prize, drawn by our Assoc. Chair, is Ali Reza Sharafat, a grade 12 student from Lisgar Collegiate Institute, Ottawa. Congratulations Ali! A copy of "Astronomy - Journey to the Cosmic Frontier" by John D. Fix has been mailed to you.

DERANGED SCIENTISTS - BONUS PUZZLE NOBEL LAUREATES WITH CANADIAN CONNECTIONS By popular request (well, the editor asked me!), here is another puzzle involving five more Nobel Laureates who were either Canadians or had strong associations with Canada. Unscramble the letters below to form the names of these scientists. Then use the letters with asterisks to find the name of the fifth scientist in this category. Note that several of the scientists are not physicists and none of them were featured in our earlier Canadian puzzle #10. Send your entries to reach us before March 1, 2004. (Please include your full name, affiliation and address). MAIL: FAX: E-MAIL:

R. Jayasundera, Department of Physics, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada (519) 746-8115 - attention of R. Jayasundera [email protected]

A draw for a book prize will be made from all correct entries. This contest is open to all readers of Phys 13 news. The solution and the winner's name along with the biographical sketches of these five scientists will appear in the next issue of the magazine.

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THISM S H O W C LAW TA M LA N FURTHERDOR

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SOLUTION Page 14

Phys 13 News / Winter 2004

THE SIN BIN A problem corner intended to stimulate some reader participation. The best valid solution to the problem will merit a book prize. We will always provide a book prize for the best student solution. Send your favourite problems and solutions to our BINkeeper, John Vanderkooy, [email protected]. Problem 109 We received the correct solution from Ali Reza Sharafat, who also sent the correct solution for the Laureates Puzzle and happened to win the draw. Lucky Ali! It would be nice if we had more solutions from students! To promote more student involvement the problems for the next while, although challenging, can be done by students even if they have not finished all their physics. Eg. the problem below needs a little bit of optics, but geometrical reasoning will get you a long way. Of course we expect that teachers and others alike will still send in their solutions! We continue on the theme of energy use in the future and consider a society that wants to use the Sun for everything. The flux of energy from the Sun near Earth is 1400 W/m2. What we want to do with mirrors orbiting the moon is to illuminate its dark side (people on Earth still want to sleep at night…) in order to grow plants in biospheres continuously. The Sun has a diameter of 1.4 × 109 m and is 1.5 × 1011 m away. The moon has a diameter of 3.5 × 106 m. To the best of your ability, find the minimum mirror size, radius of curvature of the mirror, and orbit height from the moon which will allow us to have a radiant flux of 400 W/m2 at the moon? You may assume that all the energy striking the mirror will end up on the dark side of the moon, uniformly illuminating it. To guide your thinking, if we used a very large flat mirror behind the moon, the flux would be close to 1400 W/m2, since this merely reflects the sunlight near Earth undiminished to the dark side of the moon. Of course only a small portion of the mirror would be needed.

about 200 km × 50 km, and is 80 m deep, how long will the water in the lake supply Ontario’s power needs of about 20 gigawatts? Assume that Lake Ontario keeps its level as water drains out the St. Lawrence River, and that no other water drains into Lake Erie, so that the lake will be depleted to produce the power. I had the feeling that this would give an almost inexhaustible supply of power, but numbers do have to be respected… The Solution! Thanks to Chris Curran for a correct solution. I still keep hoping that students will send in a solution! Perhaps the realities of physics teaching are such that there is very little time for that extra hour… The potential energy of the water in Lake Erie can be calculated based on centre-of-gravity concepts. The CG will be halfway between the top and bottom of the lake, so if the total volume of the lake is V, the density ρ, and the height of the centre of gravity h=40m, then the potential energy of all this water E is: E = V ρ g h = 80 × 200000 × 50000 × 1000 × 9.8 × 40 = 3.136 × 1017 joules. If this energy is used to produce power P (2 × 1010 W) over a time t, then E = P × t, thus t = E / P = 3.136 × 1017 / 2 × 1010 = 1.568 × 107 seconds = 181.5 days. Thus all of Lake Erie would be depleted in 6 months. My initial guess was for a much longer time period! We certainly are massive energy consumers.

World's Easiest Quiz The questions below appear to be straight-forward but don't be fooled. Only four correct answers will give you a passing grade. (answers on back cover).

Problem 108 from last issue: We keep on the theme of energy in this issue and now want to supply Ontario’s electrical power requirements by using water from Lake Erie. It is about 80 m above Lake Ontario. If we assume that Lake Erie has a surface area of

Phys 13 News / Winter 2004

1) 2) 3) 4) 5) 6) 7) 8) 9) 10)

How long did the Hundred Years War last? Which country makes Panama hats? From which animal do we get catgut? When do Russians celebrate the October Revolution? What is a camel's hair brush made of? What animal are the Canary Islands named after? What was King George VI's first name? What colour is a Purple Finch? Where are Chinese Gooseberries from? What's the colour of the black box in an airplane?

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cont'd from pg 7

A single 40x32 sub-array

on the order of 100 times greater than any existing camera for this wavelength region. Since existing technology is not scalable to such pixel counts, it has been necessary to develop a new approach incorporating superconducting Transition-Edge Sensors (TES) linked to multiplexed SQUID (Superconducting Quantum Interference Device) amplifiers. Such innovative new technology has applications for future astronomical missions as well as a range of industrial, security, and medical applications (e.g. X-ray spectrometers for diagnosing contaminants in silicon chip fabrication lines and detectors for medical imaging). Each pixel of SCUBA-2 will be more sensitive and more stable than the SCUBA pixels such that in common usage the sensitivity will be only limited by the background of the sky. The design for a typical pixel is shown in Fig. 9 while Fig. 10 shows the lay-out for several pixels in a regular grid. Detector wafer

Fig. 11: The focal plane assembly for 850 microns showing four sub-arrays fitted together (at the top). The wide copper bands coming out at the bottom on each side are the cables that connect the detectors to the electronics that controls the camera and reads out the data.

Absorber and TES

Multiplexer wafer Bump bonds

Fig. 10: Several pixels laid out in a rectangular grid. Note that there are two wafers, a detector wafer and a multiplexor wafer, and these are connected together by “bump bonds”, a very high technology technique.

Due to the physical size of the pixels and limitations on the fabrication of an individual wafer, SCUBA-2 will use four sub-arrays of 40 by 32 pixels at each wavelength, fitted together as shown in Fig. 11. These sub-arrays will come very close to filling the focal plane of the JCMT and therefore covering all of the area where the light collected by the telescope is brought to a focus to create an image of the sky. SCUBA-2 is scheduled to have the first prototype arrays completed in early 2004, and the plans will have the camera ready for installation in late 2005 with first science operations in May 2006 after extensive commissioning and testing of the instrument on the telescope. In the year following the first science usage of the SCUBA-2 the camera will be augmented with “ancillary” instruments, a polarimeter (to be made at Université de Montréal) and a spectrometer (to be made a the University of Lethbridge). By early 2007 this will be a fully operating submillimetre camera, the best in the world, and Canadian astronomers can expect to continue in their leading role in this field.

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Phys 13 news is published four times a year by the Physics Department of the University of Waterloo. Our policy is to publish anything relevant to high school and first-year university physics, or of interest to high school physics teachers and their senior students. Letters, ideas, and articles of general interest with respect to physics are welcome by the editor. You can reach the editor by email at: [email protected]. Alternatively you can send all correspondence to: Phys 13 news, Physics Department University of Waterloo Waterloo, Ontario N2L 3G1 Online editions can be viewed at: www.science.uwaterloo.ca/physics/p13news Editor:

Guenter Scholz

Editorial Board:

Tony Anderson, Rohan Jayasundera, Jim Martin, Chris O'Donovan, Guenter Scholz, Thomas Thiemann, John Vanderkooy and David Yevick

Publisher:

Judy McDonnell

Printing:

UW Graphic Services Department

Phys 13 News / Winter 2004

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Answers to the World's Easiest Quiz: 1) 2) 3) 4) 5) 6) 7) 8) 9) 10)

Phys 13 News / Winter 2004

116 years Ecuador Sheep and Horses November Squirrel fur Dogs Albert Crimson New Zealand Orange, of course.

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