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Nicole Ackerman | SLAC | USA

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DPF in Detroit (part I)

Wednesday, July 29th, 2009

On Saturday I flew to Detroit where I am participating in the APS Division of Particle and Fields conference at Wayne State University. This was exciting for me as I both get to present an EXO talk and I get to return to my “homeland”. This is the first time I’ve been back to Michigan in over 5 years. I’m spending my time outside of the conference catching up with family, friends, and seeing the area.

The conference has been full of exciting physics, and I’m not yet to the end of the 2nd day! There are 4 parallel sessions, and each one has a neutrino session. In addition to the big accelerator based experiments (like MINOS and NOvA) there have also been theory talks, astrophysical neutrino talks, and representation from the smaller experiments. Unfortunately some of the neutrino talks are in other parallel sessions, like the particle-astro or “Low energy searches for physics beyond the standard model”, and I’ve had to choose between two really interesting talks. I’ve heard about an new analysis method that could be applicable to EXO, hierarchy tests with supernova neutrinos, and tests for Lorentz violations with neutrinos. I’ve always thought that neutrinos were an exciting and fast developing field, but I am still surprised by everything they can be related to!


WiTricity: A revolution from physics?

Thursday, July 23rd, 2009

I was quite excited when the development of “witricity” was announced – the ability to transmit power without wires. It’s amazing in its simplicity – it doesn’t require carbon nanotubes or rare elements – just electromagnetic fields and a bit of resonance. It works in a similar way to a radio transmitter and receiver – something creates an electromagnetic field with certain properties, and another device detects those fields. A normal transformer – the thing that converts 120 Volts AC into something your laptop can use – even uses a similar principle, but the distance is really small and the field is passed through iron.

Diagram shows how magnetic fields transmit power, even around obstacles (from WiTricity Corportation)

Diagram shows how magnetic fields transmit power, even around obstacles (from WiTricity Corportation)

I was re-excited when I read an article in BBC news saying that the WiTricity Corporation has demonstrated a system (ie, something destined for consumers!) at the TED conference. I remember making a guess of how long it would take for the product to hit markets – I don’t remember what the exact timescale was predicted to be, but it certainly looks fairly soon!

I will admit to not having followed the development over the past few years, so I had feared that the WiTricity Corporation was somehow (unfairly?) profiting from the hard work of the MIT physicists who developed it. I am quite happy to see that the management team seems to be made up of the original scientists (as well as a few others) and that there is a Scientific Advisory Board of MIT Professors who worked on the development as well. Additionally, Prof. Soljačić received the MacArthur Fellowship (aka Genius Grant) for the work. So not only did a few physicists create an invention that may revolutionize consumer technology, but they received scientific recognition, and stand to actually receive the financial windfall as well! I think this represents the luckiest few graduate students since Larry Page and Sergey Brin!


The Physics Talk

Saturday, July 18th, 2009

I’m in the process of preparing a talk for an upcoming conference. More specifically, I’m preparing a physics talk. I always battle to find the compromise between giving a good talk and creating a good physics presentation, which seem to be different.

I did competitive speaking in high school (with no visual aids!) so I’m never too nervous about giving a talk. More honestly, I am used to my knees shaking. In general, a key to a good talk is to use the slides as visual aids to emphasize particular content. There shouldn’t be too much info presented on a single slide, and as few words as possible. The first few presentations I gave involving physics could obey these rules – they were oral reports for an undergraduate lab and a presentation for parents. All of the feedback I received from professors and communications experts were always to get rid of the words and simplify the slides.

Now I’m in the world of “real” physics talks and the rules have changed, for relatively good reasons. Slides do not just serve as visual aids, but as a resource to people who missed the talk or who want to refresh their memory later. In this case the chart or picture needs to be accompanied with analysis or some sort of summary of what was said. While the warning against words on a slide was that the audience would read the slides instead of listening to the presenting, now this has become a blessing. I’ve seen talks where I can’t understand the presenter and I’m thankful I can get all of the content out of the presentation.

One example: if I show a diagram of the detector on a slide, the “better” presentation style would to have it large, with few words. Perhaps I could have a few slides with the same picture and a different component highlighted on each one. The “physics way” is to have each component labeled with a small description. I’m still erring on the side of the minimalist talk – I’m just giving a talk in a parallel session that others will not want to read later.


Physics Family Trees

Sunday, July 12th, 2009

In a variety of fields of science, people keep track of their “academic family tree”. I’ve seen it traced through PhD advisors, but perhaps other fields do it somewhat differently. It isn’t as common in experimental physics as it is in other fields – some specialties have their own websites – but I hear theorists value it more.

Recently I saw an article in Symmetry Magazine regarding the physics family tree. While I absolutely love Spires, I had never explored the HEPNAMES section before. It isn’t perfectly up-to-date; it seems to rely on self-reporting. However, I did learn some things. I already knew that my “academic grandfather” was Jerome Friedman, one of the winners of the 1990 Nobel Prize. I did not know that his advisor was Enrico Fermi! Interestingly, of the 14 students listed on HEPNAMES for Enrico Fermi, 7 have the Nobel Prize. It seems like the people who run Spires have a great sense of humor – physicists who have retired, passed away, or left physics are signified with an icon. The icon for “left physics” is a dollar sign!


Tools of the trade

Friday, July 10th, 2009

Computers are supposed to be great tools, allowing us to be more efficient and complete tasks not previously possible. Most of us may feel differently during the course of the day – whether it is seg-faults or viruses or compatibilities issues – but I realize that computers significantly change how I do my job. Physics analysis itself has changed from doing log-log plots or scanning images to neural-nets categorizing and plotting millions of events. When I think of the tools that make my job easier, I think of specific computer programs:

Latex Beamer is what I use to make presentations. I often create latex documents as notes, so I have tables and equations ready to go into a presentation if I use latex, rather than needing to recreate everything if I use OpenOffice Presentation. I tried different latex classes for creating presentations, and beamer is my favorite. It even comes with a 224-page user guide. Beamer was created by someone who couldn’t find the right tool for creating his dissertation.

Zotero has freed me from printing every paper I am interested in reading or referencing in the future. Zotero is a way of bookmarking papers (and pretty much everything else) in different libraries, attributing meta-data, creating timelines, and exporting bibliographies. The new version even will sync your data with the zotero server so that it can be available on multiple computers.

ELOG is what I use to take notes in meetings and organize my thoughts. I run my own elog on my laptop, but my experiment also uses it. When I had a fixed IP I mirrored it so I could access my notes from anywhere. Since the source is available, I was able to modify it to recognize latex commands and display them as MathML. I consider getting latex into elog to be one of my greatest achievements.

I’m stuck right now at (more or less) the beginning of an extensive literature review. How do I keep notes on the papers? I want to do out calculations, so it seems like pen and paper is necessarily. I need to keep track of dates and the relationships between the papers, so it seems like Zotero would be helpful. There are some questions I need to answer about each paper, so maybe a spreadsheet is right. I’m starting by using all of these, but I wonder if it worth the time for me to write a tool that would combine all of the features I need. Seeing how I barely have time to actually read the papers, it doesn’t seem like I should dump time into the infrastructure.


Food and other elements

Friday, July 3rd, 2009

Two weeks ago I saw the new documentary “Food, Inc” in San Francisco. It was very enjoyable with much of its content based on the books The Omnivore’s Dilemma and Fast Food Nation, both of which I hadn’t read prior to the movie. I now own both books and have started reading The Omnivore’s Dilemma. As a scientist, I like receiving information as “objectively” as possible. There is always some level of subjectivity – even in particle physics – but journalism tends to balance objectivity with the sensationalism that will actually sell books, newspapers, or magazines. I certainly hope that this book is heavier on the facts than sensationalism.

I haven’t made it very far yet, but I was disappointed to find the phrase “Next to water, carbon is the most abundant element in the body…” I understand what he was trying to say, but he fell a little short by implying that water is an element. Later he deals with some of the chemistry of carbon capture in corn, but his notation makes it very unclear. He uses “C-4” to denote a molecular process where 4 atoms of corn are processed, which would be more clear as C4.  He also refers to different isotopes as “C-13”, where it would be correct to use 13C or carbon-13.  Why does he choose to use the SAME wrong notation for both molecular and nuclear specifications? Later, he describes the means by which corn reproduces (ie, pollination) and the genetic mutations responsible for turning teosinte grass into zea mays (corn). He refers to the “changes on as few as four chromosomes” as “teosinte’s sex change”. His description of “corn sex” is disturbingly anthropomorphic, and includes the phrase “the male anthers resemble flowers and the female cob a phallus”, which he considers an “oddity in the sex life of corn”. Last time I checked, plant reproduction usually is not broken down into a flower and phallus – often the “male” and “female” parts all reside in the flower (see the lily). This not only offends my scientific sensibilities, but also my feminist ones as well.

How is it he manages to violate both high school chemistry and biology in the first chapter? Did neither he nor his editor (nor any of the others who may have done early readings of the text) have a basic understanding of high school science? Was it decided that using proper chemistry notation would scare off readers? Was the sensationalism of corn sex (and sex change) more interesting than a mature discussion of corn reproduction? I’m not so offended that I will stop reading, but I am certainly disappointed.


Steven Chu: Tomorrow is Today

Friday, June 26th, 2009

This morning, Secretary of Energy Dr. Steven Chu spoke at SLAC. At a national scale, Secretary Chu is notable since he is a Nobel-prize winning physicist. Locally, he is well known since he was a professor at Stanford (and Physics Department Head) and was most recently the director of the Lawrence Berkeley National Laboratory, which is geographically close to SLAC.

I expected his talk to focus on SLAC and the relationship between the DOE and the National Labs. He began by discussing how the DOE has supported the work of 88 Nobel Laureates and assuring us that basic science research was a priority for him. While the DOE may be often seen as involved in nuclear weapons and power or energy research, to many of us it is the main funder of basic science work. It is refreshing to know that the head of DOE shares that idea.

The majority of his talk focused on climate change and what we can do to reduce emissions. This is an issue he worked on before he was head of the DOE and he is now in an excellent position to make progress. It was very useful to see climate change discussed in terms of data, plots, and 90% confidence intervals, rather than the usual ideological arguments. I can see how certain pundits twist the data – there was one prediction in the early 90’s regarding a certain climate change parameter that did not match the measurements taken since. While one can say, “Wow, that data is outside of the 90% confidence error bars so climate scientists really don’t know what they are doing” – it is important to realize that the prediction underestimated the change. Likewise, he showed that there is a carbon cycle in the earth’s crust that has been mapped out for the past 800,000 years. Yes it is a cycle, but the current value is outside of the amplitude of this cycle and it is predicted to get much, much worse. The earth has seen temperature changes of 6 degrees before, but those changes occurred over thousands of years, so that adaptation was possible. We’re looking at a change of 6 degrees of 100 years – adaptation does not happen that quickly. These are all details that get lost in normal news coverage of the climate change “controversy”. Perhaps we don’t know all of the details yet, but the data still makes it look like the world is going to end.

His talk was not just doom and gloom – it was a challenge for us to apply our “intellectual horsepower” to the problems at hand. He discussed how a predicted fertilizer shortage in the early 1900’s was averted through the creation of artificial fertilizer. Predictions in the 1960’s that the world would run out of food were wrong because of new grain hybrids created to grow more efficiently. If the world doesn’t end, it won’t be because our data is wrong. It will be due to the scientific achievements of the next few decades.

He ended with a brilliant quote from Martin Luther King, Jr:

We are now faced with the fact, my friends, that tomorrow is today. We are confronted with the fierce urgency of now. In this unfolding conundrum of life and history, there is such a thing as being too late.

I thought about summarizing the numbers and data that he presented, but it is too extensive for me to do it justice. Instead, I will point you to the Technical Summary of the Intergovernmental Panel on Climate Change. It is 74 pages of data and plots regarding patterns in the ice, atmosphere, temperature, and precipitation of our planet. As a scientist, I look and see that our climate is changing. Secretary Chu’s response to those who question the ideas of climate change was “People are entitled to their own opinions, but they are not entitled to their own facts.”


Physics and Celebrity

Tuesday, June 23rd, 2009

Susan Boyle has risen to fame after being mocked for her interest in fame and success. So here I go – I want to be famous. She wanted to be as successful at Elaine Paige. Who would I model my success after, if I were given the chance?

Neil DeGrasse Tyson

Neil DeGrasse Tyson

Just as Susan Boyle did not want to be as successful as say, Madonna or Britney Spears, the physicists with the most air time are not my biggest role models. Stephen Hawking may have been featured on The Simpsons, but his fame is more about him personally, rather than his science. I think Neil deGrasse Tyson is a very successful physics “celebrity” – he’s been on The Colbert Report 5 times – but his appearances are about science as much as they are about him. I don’t necessarily want to be on The Daily Show, or late night television, but being called on as an expert for a Nova show would be pretty awesome. I certainly wouldn’t want to go onto a reality show – as a MIT grad, I’d be stuck in a geek role.

My true dream (and if only there was a reality show for this) would be to be a science consultant for tv or movies. I certainly don’t want to run away to Hollywood, but I’d love to be called up someday to make sure that the background for a “science” shot looks more like an actual lab than the back of a Spencer Gift’s store. I worked at a store called Glow!, where I saw many plasma lamps and plates (pictured below). I’ve sadly even seen them in “labs” in Stargate SG-1 but have never seen one actually being used for science. So Hollywood – feel free to give me a call. My business cards are already made. And if you’d rather have some spiffy looking glowing things in the background – rather than actual scientific devices – I can hook you up with that as well.

Plasma Plate

Plasma Plate - fun decoration, but not in a scientific lab!


Commencement Tours of SLAC

Thursday, June 18th, 2009

Stanford’s commencement was this past weekend, and one of the activities celebrating families could choose was a tour of SLAC. I happily volunteered to be a tour guide – I’ve actually wanted to be a SLAC tour guide for some time. I planned to “try out” to be a tour guide when I began graduate school, but the SLAC tour program went on hiatus shortly after I arrived. Now that tours will be starting up again – in the fall – I really wanted to do a commencement tour. I liked it, and I’m optimistic that I’ll get better at it with some practice.

Inside the Klystron Gallery. (Photo by Nicholas Bock.)

Inside the Klystron Gallery. (Photo by Nicholas Bock.)

In some ways, commencement tours are more difficult than “normal” tours. Talking to a tour bus of 50 people, it is hard to gauge reactions and interest. The majority of the “tour” occurs as the bus is driving from Stanford to SLAC, so the guide must fill about 20 minutes with material before the visitors have even seen the accelerator. The normal tours given at SLAC tend to be to a specific group of people: high school physics class, researchers visiting campus, or a large family on vacation. Some people may find the rich history of SLAC interesting, others may appreciate the recent work done at the Stanford Synchrotron Radiation Lightsource (SSRL). With a commencement tour, each family has a wide range of expertise and interest.

I tried to anticipate the questions I might get asked: What is the main difference between SSRL and LCLS? How does a klystron work? What is the maximum distance of acceleration that plasma wakefield has ever been sustained? What is the longest SLAC has gone between accelerator upgrades? I tried to prepare for the more obvious questions – likely about CERN and the LHC – but I was terrified of being quizzed on the details of SLAC’s long history. I hated that I might have to reply with “I’m just a graduate student, I don’t know” since I was a representative of SLAC. I’ve grown more comfortable with giving that answer during scientific talks, but I was hoping to not face it during tours. I ended up being asked very few questions – thankfully, none about the LHC destroying the world. I hope all visitors left having learned something about SLAC, and hopefully more interested in the science we do here.



Monday, June 15th, 2009

Installing APD's

Installing APD's

Today is a milestone in my scientific career: I gained a SPIRES entry. I feel disingenuous saying “I published a paper” – many people did a great deal of work for the paper (their names come before mine) and all I did was join EXO. From here, I can next look forward to making a sizeable enough contribution to move from the alphabetized collaborator part of the author list to being a “numbered” author – but that may be quite far off.

Author lists can be a tricky thing. Large collaborations have complicated policies about who is on what papers, since it is difficult to say who really contributed to a given result. Once we are publishing data-dependent papers, it will be the result of the work everyone has put into commissioning at WIPP, writing the Monte Carlo, designing the electronics, building the detector, installing the veto system, and measuring the radiopurity of our materials. It won’t just be the work of whoever wrote the code to fit for a number.