## Posts Tagged ‘coffee’

### Life Underground: Anything Anyone Would Teach Me

Friday, April 17th, 2015

Going underground most days for work is probably the weirdest-sounding this about this job. At Laboratori Nazionali del Gran Sasso, we use the lab to be underground because of the protection it affords us from cosmic rays, weather, and other disruptions, and with it we get a shorthand description of all the weirdness of lab life. It’s all just “underground.”

The last kilometer of road before reaching the above-ground labs of LNGS

Some labs for low background physics are in mines, like SURF where fellow Quantum Diariest Sally Shaw works. One of the great things about LNGS is that we’re located off a highway tunnel, so it’s relatively easy to reach the lab: we just drive in. There’s a regular shuttle schedule every day, even weekends. When there are snowstorms that close parts of the highway, the shuttle still goes, it just takes a longer route all the way to the next easy exit. The ride is a particularly good time to start drafting blog posts. On days when the shuttle schedule is inconvenient or our work is unpredictable, we can drive individual cars, provided they’ve passed emissions standards.

The guards underground keep a running list of all the people underground at any time, just like in a mine. So, each time I enter or leave, I give my name to the guards. This leads to some fun interactions where Italian speakers try to pronounce names from all over. I didn’t think too much of it before I got here, but in retrospect I had expected that any name of European etymology would be easy, and others somewhat more difficult. In fact, the difficult names are those that don’t end in vowels: “GladStone” become “Glad-eh-Stone-eh”. But longer vowel-filled names are fine, and easy to pronounce, even though they’re sometimes just waved off as “the long one” with a gesture.

There’s constantly water dripping in the tunnel. Every experiment has to be housed in something waterproof, and gutters line all the hallways, usually with algae growing in them. The walls are coated with waterproofing, more to keep any potential chemical spill from us from getting into the local groundwater than to keep the water off our experiments. When we walk from the tunnel entrance to the experimental halls, the cue for me to don a hardhat is the first drip on my head from the ceiling. Somehow, it’s always right next to the shuttle stop, no matter where the shuttle parks.

And, because this is Italy, the side room for emergencies has a bathroom and a coffee machine. There’s probably emergency air tanks too, but the important thing is the coffee machine, to stave off epic caffeine withdrawal headaches. And of course, “coffee” means “espresso” unless otherwise stated– but that’s another whole post right there.

When I meet people in the neighboring villages, at the gym or buying groceries or whatever, they always ask what an “American girl” is doing so far away from the cities, and “lavoro a Laboratorio Gran Sasso” is immediately understood. The lab is even the economic engine that’s kept the nearest village alive: it has restaurants, hotels, and rental apartments all catering to people from the lab (and the local ski lift), but no grocery stores, ATMs, gyms, or post offices that would make life more convenient for long-term residents.

Every once in a while, when someone mentions going underground, I can’t help thinking back to the song “Underground” from the movie Labyrinth that I saw too many times growing up. Labyrinth and The Princess Bride were the “Frozen” of my childhood (despite not passing the Bechtel test).

Just like Sarah, my adventures underground are alternately shocking and exactly what I expected from the stories, and filled with logic puzzles and funny characters. Even my first night here, when I was delirious with jetlag, I saw a black cat scamper across a deserted medieval street, and heard the clock tower strike 13 times. And just like Wesley, “it was a fine time for me, I was learning to fence, to fight–anything anyone would teach me–” (except that in my case it’s more soldering, cryogenics plumbing, and ping-pong, and less fighting). The day hasn’t arrived where the Dread Pirate Roberts calls me to his office and gives me a professorship.

And now the shuttle has arrived back to the office, so we’re done. Ciao, a dopo.

(ps the clock striking 13 times was because it has separate tones for the hour and the 15-minute chunks. The 13 was really 11+2 for 11:30.)

### A Physicist and Historian Walk Into a Coffee Shop

Saturday, July 26th, 2014

It’s Saturday, so I’m at the coffee shop working on my thesis again. It’s become a tradition over the last year that I meet a writer friend each week, we catch up, have something to drink, and sit down for a few hours of good-quality writing time.

The work desk at the coffee shop: laptop, steamed pork bun, and rosebud latte.

We’ve gotten to know the coffee shop really well over the course of this year. It’s pretty new in the neighborhood, but dark and hidden enough that business is slow, and we don’t feel bad keeping a table for several hours. We have our favorite menu items, but we’ve tried most everything by now. Some mornings, the owner’s family comes in, and the kids watch cartoons at another table.

I work on my thesis mostly, or sometimes I’ll work on analysis that spills over from the week, or I’ll check on some scheduled jobs running on the computing cluster.

My friend Jason writes short stories, works on revising his novel (magical realism in ancient Egypt in the reign of Rameses XI), or drafts posts for his blog about the puzzles of the British constitution. We trade tips on how to organize notes and citations, and how to stay motivated. So I’ve been hearing a lot about the cultural difference between academic work in the humanities and the sciences. One of the big differences is the level of citation that’s expected.

As a particle physicist, when I write a paper it’s very clear which experiment I’m writing about. I only write about one experiment at a time, and I typically focus on a very small topic. Because of that, I’ve learned that the standard for making new claims is that you usually make one new claim per paper, and it’s highlighted in the abstract, introduction, and conclusion with a clear phrase like “the new contribution of this work is…” It’s easy to separate which work you claim as your own and which work is from others, because anything outside “the new contribution of this work” belongs to others. A single citation for each external experiment should suffice.

For academic work in history, the standard is much different: the writing itself is much closer to the original research. As a start, you’ll need a citation for each quote, going to sources that are as primary as you can get your hands on. The stranger idea for me is that you also need a citation for each and every idea of analysis that someone else has come up with, and that a statement without a citation is automatically claimed as original work. This shows up in the difference between Jason’s posts about modern constitutional issues and historical ones: the historical ones have huge source lists, while the modern ones are content with a few hyperlinks.

In both cases, things that are “common knowledge” doesn’t need to be cited, like the fact that TeV cosmic rays exist (they do) or the year that Elizabeth I ascended the throne (1558).

There’s a difference in the number of citations between modern physics research and history research. Is that because of the timing (historical versus modern) or the subject matter? Do they have different amounts of common knowledge? For modern topics in physics and in history, the sources are available online, so a hyperlink is a perfect reference, even in formal post. By that standard, all Quantum Diaries posts should be ok with the hyperlink citation model. But even in those cases, Jason puts footnoted citations to modern articles in the JSTOR database, and uses more citations overall.

Another cool aspect of our coffee shop is that the music is sometimes ridiculous, and it interrupts my thoughts if I get stuck in some esoteric bog. There’s an oddly large sample of German covers of 30s and 40s showtunes. You haven’t lived until you’ve heard “The Lady is a Tramp” in German while calculating oscillation probabilities. I’m kidding. Mostly.

Jason has shown me a different way of handling citations, and I’ve taught him some of the basics of HTML, so now his citations can appear as hyperlinks to the references list!

As habits go, I’m proud of this social coffee shop habit. I default to getting stuff done, even if I’m feeling slightly off or uninspired.  The social reward of hanging out makes up for the slight activation energy of getting off my couch, and once I’m out of the house, it’s always easier to focus.  I miss prime Farmers’ Market time, but I could go before we meet. The friendship has been a wonderful supportive certainty over the last year, plus I get some perspective on my field compared to others.

### No cream, no sugar

Monday, January 6th, 2014

My first visit to CERN was in 1997, when I was wrapping up my thesis work. I had applied for, and then was offered, a CERN fellowship, and I was weighing whether to accept it. So I took a trip to Geneva to get a look at the place and make a decision. I stayed on the outskirts of Sergy with my friend David Saltzberg (yes, that David Saltzberg) who was himself a CERN fellow, and he and other colleagues helped set up appointments for me with various CERN physicists.

Several times each day, I would use my map to find the building with the right number on it, and arrive for my next appointment. Invariably, I would show up and be greeted with, “Oh good, you’re here. Let’s go get a coffee!”

I don’t drink coffee. At this point, I can’t remember why I never got started; I guess I just wasn’t so interested, and may also have had concerns about addictive stimulants. So I spent that week watching other people drink coffee. I learned that CERN depends on large volumes of coffee for its operation. It plays the same role as liquid helium does for the LHC, allowing the physicists to operate at high energies and accelerate the science. (I don’t drink liquid helium either, but that’s a story for another time.)

Coffee is everywhere. In Restaurant 1, there are three fancy coffee machines that can make a variety of brews. (Which ones? You’re asking the wrong person.) At breakfast time, the line for the machines stretches across the width of the cafeteria, blocking the cooler that has the orange juice, much to my consternation. Outside the serving area, there are three more machines where one can buy a coffee with a jeton (token) that can be purchased at a small vending machine. (I don’t know how much they cost.) After lunch, the lines for these machines clogs the walkway to the place where you deposit your used trays.

Coffee goes beyond the restuarants. Many buildings (including out-of-the-way Building 8, where my office is) have small coffee areas that are staffed by baristas (I suppose) at peak times when people who aren’t me want coffee. Building 40, the large headquarters for the CMS and ATLAS experiments, has a big coffee kiosk, where one can also get sandwiches and small pizzas, good when you want to avoid crazy Restaurant 1 lunchtimes and coffee runs. People line up for coffee here during meeting breaks, which usually puts us even further behind schedule.

Being a non-drinker of coffee can lead to some social discomfort. When two CERN people want to discuss something, they often do it over coffee. When someone invites me for a chat over coffee, I gamely say yes. But when we meet up I have to explain that I don’t actually drink coffee, and then sit patiently while they go to get a cup. I do worry that the other person feels uncomfortable about me watching them drink coffee. I could get a bottle of water for myself — even carbonated water, when I feel like living on the edge — but I rarely do. My wife (who does drink coffee, but tolerates me) gave me a few jetons to carry around with me, so I can at least make the friendly gesture of buying the other person’s coffee, but usually my offer is declined, perhaps because the person knows that he or she can’t really repay the favor.

So, if you see a person in conversation in the Restaurant 1 coffee area, not drinking anything but nervously twiddling his thumbs instead, come over and say hello. I can give you a jeton if you need one.

### Why India is a Modern Country

Friday, April 20th, 2012

–by Nigel S. Lockyer, Director

I am back in India to attend the first International Advisory Committee meeting for the ANURIB project at VECC. It is hard to ignore how rapidly India is changing. But to have some fun with them, I came up with the Top Ten reasons India is a Modern Country.

1. It is Saturday, April 15th, Nabobarsho, the Bengali new year. Poila Baisakh is the first day of the new year and is cause for celebrations and speeches by politicians. A sign of the times was the message was sent out in West Bengal by Chief Minister Mamata Banerjee to millions of cell-phone users.
2. Katy Perry opened the India Premier League’s opening cricket game….OK, not a reason.
3. Kolkata has just launched its first online radio station
4. Attention squirrel lovers: The India forest department is using satellites to track down giant squirrels. What the heck are giant squirrels? Apparently they look like cats with long tails (2 feet) and weigh about 4-5 pounds. They are famous for jumping 20 feet between branches. The head and body of this scary animal is up to sixteen inches in length, compared to the ten of the Eastern Gray found in the US.  Relax, it is herbivorous!
5. MS Dhoni, the cricket star, just signed a contract worth 200 crore or about $40M. With his TV contracts etc. he pulls in about 700 crore or$140M. Still waiting for his team to win a championship!
6. The AC power adapter in my hotel room is universal. No need to carry around an adapter. Time to return the one CERN DG Rolf Heuer gave me several years ago that was useful about 50% of the time.
7. Recently famous Bengali native Shah Rukh Khan (locally referred to as SRK) was detained in a NY airport because of his name. King Khan, the Bollywood superstar just laughed it off. However we hear the U.S. envoy was called to New Delhi for explanation. The U.S. said they have now invented and are ready to release an automatic South Asian apology machine for such cases—and the software was written by Indians!
8. I couldn’t get a beer in the Mumbai hotel bar after 1:30 AM. Last call!
9. Next evening I ordered a Kingfisher (a national Indian beer and quite good) and all they had was Heineken.
10. Variable Energy Cyclotron Centre (VECC) in Kolkata is starting Phase I of a major new “green field” initiative in Rare Isotope Beam physics called ANURIB in Rajarhat, near the Kolkata airport. ANURIB is building off their present cyclotron driven RIB program. It involves a 100 kW, 50 MeV electron linac driver, a post accelerator, a cyclotron to raise the energy to over 100 MeV per nucleon and then a fragment separator. A very ambitious vision for India and it is getting strong support from the Government of India. Congratulations, VECC!

### Travelling 10,000 miles for breakfast

Tuesday, April 17th, 2012

–by T. “Isaac” Meyer, Head of Strategic Planning & Communication

I am on location in Kolkata, India, at the Variable Energy Cyclotron Centre (VECC). It took me 36 hours travel time to get here from Vancouver, including two red-eye plane flights. It feels like 42 deg C outside and the computer firewalls are configured so that I cannot send or receive e-mail from my laptop. And the tap water is not potable.

Why did I come?

To have breakfast with scientific peers from around the world (RIKEN in Japan, ESS in Sweden, Cockcroft Institute in the UK, VECC and IUAC and BARC here in India, and so on). Okay, not just breakfast. Also a few lunches and dinners.

Of course, we actually came together to participate in the International Advisory Committee meeting for VECC and its proposed ANURIB project and the subsequent VECC/TRIUMF semiannual collaboration meeting. It still sounds like a cliché, but the reason we attend these meetings in person is because of the sidebar conversations.

At a single breakfast meeting with three colleagues, I got updated on the budget situation for UK science, learned why Higgs spectroscopy is so intrinsically compelling that its worth several billion dollars, reviewed Japanese recovery from the earthquake & tsunami, debated “coal smuggling” in West Bengal, speculated on the international flow of in-demand talented workers in accelerator physics & engineering, and re-learned the rules for scoring in cricket. I also drank four cups of masala tea.

In global computing and networking, the experts still say, “Never underestimate the bandwidth of an overnight package stuffed full of DVDs.”

In global science, I’d say, “Never underestimate the amount of collaboration & partnership that is supported by flying people 10,000 miles to share a coffee break.”

25-acre Rajarhat site of VECC...soon to contain a world-leading electron accelerator and isotope laboratory

### That’s Right, Count Them: 4 Quarks

Friday, January 20th, 2012

Hi All,

Exciting news came out the Japanese physics lab KEK (@KEK_jp, @KEK_en) last week about some pretty exotic combinations of quarks and anti-quarks. And yes, “exotic” is the new “tantalizing.” At any rate, I generally like assuming that people do not know much about hadrons so here is a quick explanation of what they are. On the other hand, click to jump pass “Hadrons 101” and straight to the news.

## Hadrons 101: Meeting the Folks: The Baryons & Mesons

Hadrons are pretty cool stuff and are magnitudes more quirky than those quarky quarks. The two most famous hadrons, the name for any stable combination of quarks and anti-quarks, are undoubtedly the proton and the neutron:

According to our best description of hadrons (Quantum Chromodynamics), the proton is effectively* made up two up-type quarks, each with an electric charge of +2/3 elementary charges**; one down-type quark, which has an electric charge of -1/3 elementary charges; and all three quarks are held together by gluons, which are electrically neutral. Similarly, the neutron is effectively composed of two down-type quarks, one up-type quark, and all the quarks are held strongly together by gluons. Specifically, any combination of three quarks or anti-quarks is called a baryon. Now just toss an electron around the proton and you have hydrogen, the most abundant element in the Universe! Bringing together two protons, two neutrons, and two electrons makes helium. As they say, the rest is Chemistry.

However, as the name implies, baryons are not the only type of hadrons in town. There also exists mesons, combinations of exactly one quark and one anti-quark. As an example, we have the pions (pronounced: pie-ons). The π+ (pronounced: pie-plus) has an electric charge of +1 elementary charges, and consists of an up-type quark & an anti-down-type quark. Its anti-particle partner, the π (pronounced: pie-minus), has a charge of -1, and is made up of an anti-up-type quark & a down-type quark.

If we now include heavier quarks, like strange-type quarks and bottom-type quarks, then we can construct all kinds of baryons, mesons, anti-baryons, and anti-mesons. Interactive lists of all known mesons and all known baryons are available from the Particle Data Group (PDG)***. That is it. There is nothing more to know about hadrons, nor has there been any recent discovery of additional types of hadrons. Thanks for reading and have a great day!

* By “effectively,” I mean to ignore and gloss over the fact that there are tons more things in a proton, like photons and heavier quarks, but their aggregate influences cancel out.

** Here, an elementary charge is the magnitude of an electron’s electron charge. In other words, the electric charge of an electron is (-1) elementary charges (that is, “negative one elementary charges”). Sometimes an elementary charge is defined as the electric charge of a proton, but that is entirely tautological for our present purpose.

*** If you are unfamiliar with the PDG, it is arguably the most useful site to high energy physicists aside from CERN’s ROOT user guides and Wikipedia’s Standard Model articles.

## The News: That’s Belle with an e

So KEK operates a super-high intensity electron-positron collider in order to study super-rare physics phenomena. It’s kind of super. Well, guess what. While analyzing collisions with the Belle detector experiment, researchers discovered the existence of two new hadrons, each made of four quarks! That’s right, count them: 1, 2, 3, 4 quarks! In each case, one of the four quarks is a bottom-type quark and another is an anti-bottom quark. (Cool bottom-quark stuff.) The remaining two quarks are believed to be an up-type quark and an anti-down type quark.

The two exotic hadrons have been named Zb(10610) and Zb(10650). Here, the “Z” implies that our hadrons are “exotic,” i.e., not a baryon or meson, the subscript “b” indicates that it contains a bottom-quark, and the 10610/10650 tell us that our hadrons weigh 10,610 MeV/c2 and 10,650 MeV/c2, respectively. A proton’s mass is about 938 MeV/c2, so both hadrons are about 11 times heavier than the proton (that is pretty heavy). The Belle Collaboration presser is really great, so I will not add much more.

### Other Exotic Hadrons: When Barry met Sally.

For those keeping track, the Belle Collaboration’s recent finding of two new 4-quark hadrons makes it the twelfth-or-so “tetra-quark” discovery. What makes this so special, however, is that all previous tetra-quarks have been limited to include a charm-type quark and an anti-charm-type quark. This is definitely the first case to include bottom-type quarks, and therefore offer more evidence that the formation of such states is not a unique property of particularly charming quarks but rather a naturally occurring phenomenon affecting all quarks.

Furthermore, it suggests the possibility of 5-quark hadrons, called penta-quarks. Now these things take the cake. They are a sort of grand link between elementary particle physics and nuclear physics. To be exact, we know 6-quark systems exist: it is called deuterium, a radioactive stable isotope of hydrogen (Thanks to @incognitoman for pointing out that deuterium is, in fact, stable.). 9-quark systems definitely exist too, e.g., He-3 and tritium. Etc. You get the idea. Discovering the existence of five-quark hadrons empirically establishes a very elegant and fundamental principle: That in order to produce a new nuclear isotope, so long as all Standard Model symmetries are conserved, one must simply tack on quarks and anti-quarks. Surprisingly straightforward, right? Though sadly, history is not on the side of 5-quark systems.

Now go discuss and ask questions! 🙂

Run-of-the-mill hadrons that are common to everyday interactions involving the Strong Nuclear Force (QCD) are colloquially called “standard hadrons.” They include mesons (quark-anti-quark pairs) and baryons (three-quark/anti-quark combinations). Quark combinations consisting of more than three quarks are called “exotic hadrons.”

Happy Colliding.

– richard (@bravelittlemuon)

PS, I am always happy to write about topics upon request. You know, QED, QCD, OED, etc.

http://en.wikipedia.org/wiki/Neutron

### There Will Never be Enough…

Monday, July 18th, 2011

During my brief time participating in the wide world of High Energy Physics (HEP) I have learned many, many things.   But above all, if there is one thing I’ve come to understand, it’s that there will never be enough:

# Coffee

While some people may concern themselves with blood alcohol content.  I spend my time thinking about blood caffeine content.  I’ve become thoroughly addicted as a grad student, and without my daily (or sometimes hourly) “fix,” I doubt I would get anything done.

But caffeine isn’t just my own vice (or at least that’s the addict in me talking), I’ve come to think its a necessary evil within all fields of research.  As an example, there are not one, not two, but four coffee pots on my floor of the Physics & Chemistry building; and I’m not even counting the chemistry side (or those that may be found in offices).

The coffee pot that I contribute to is filled twice a day (at least).  We go through several containers of half & half every week, along with a tub of say Maxwell House coffee.  We rely on everyone to contribute to keep this stream of liquid productivity flowing.

My own coffee mug has become to be known as “The Soup Bowl” among the grad students & professors on my floor.  I maintained that it is a coffee mug, however I’ve been fighting a losing battle ever since the start of last spring semester.  But whether its a mug for drinking coffee or a bowl for holding chicken noodle soup, I would get a whole lot less done in a day without this beautiful piece of ceramic:

My coffee mug, compared with a "normal" coffee mug

And even though this mug fits a gigantic amount of coffee; I’ve come to think that it’s never enough.

# Hours in a Day

While I need coffee to get through the hours of my day, I just really wish there were more of them.

My day begins between 8-10 am (usually depending on when I get home from the night before); I usually end up having to work until as late as 8-9pm (or sometimes even midnight) to accomplish what I need to for the day.  I spend my time corresponding with other physicists via email, attending meetings, reading papers, and computer programming.  It’s a lot of work, but I enjoy what I do.  However, I am of the opinion that the sunrise and sunset should be a bit farther apart.

"Zed, don't you guys ever get any sleep around here?" - Jay, "The twins keep us on Centaurian time, standard thirty-seven hour day. Give it a few months. You'll get used to it... or you'll have a psychotic episode." -Zed (Men In Black, 1997)

# Personnel

It’s been my experience that every single analysis in CMS can always benefit from more people becoming involved.

To give you an idea of what tasks are involved in an analysis, here’s a generic outline most conform to:

1. Define experimental techniques
2. Perform measurements
3. Determine backgrounds
4. Analyze experimental/theoretical uncertainties
5. Obtain approval (each of the LHC’s Collaborations undergo an internal peer-review process before submitting for publication in an external peer-review journal).

These tasks take time, and above all, they need warm bodies (who sometimes have more in common with Zombies, sans coffee that is).

But HEP is a collaborative science. Within a given experiment (such as CMS or ATLAS) we all work together to make sure research is conducted precisely, and promptly.  Each individual within the CMS Collaboration is usually juggling a series of different analyses.  The time they invest in each of these analyses varies.  However, each researcher usually has one project which is their “pet project,” and  occupies the majority of their time.

But needless to say, HEP is a massive undertaking, and it seems like there are never enough Physicists/Grad Students involved.

# Data

What’s the difference between one inverse femtobarn (fb-1) of data, and say ten, or a hundred??  Only a series of discoveries that will forever change our understanding of the universe.  You know, nothing major.

Humor aside, the experiments at the LHC have collected over 1 fb-1 of data this past year.  And there have been several times in which we collected more data in a day then we did in all of 2010 (which I find astounding):

Integrated luminosity delivered to/recorded by the CMS Detector per day. Note the 2010 data set consisted of only ~43.3 pb^-1. (Image Courtsey of the CMS Collaboration)

Total integrated luminosity delivered to/recorded by the CMS Detector in 2011. (Image Courtesy of the CMS Collaboration)

But what’s the big deal?  Well, one of the rules of thumb in particle physics says: to have a discovery, you need to have a statistical significance of five sigma over your current theory/background.  Simply put, the chances that your discovery is a statistical fluke must be less then 0.01%.

While this may seem a bit ad hoc, it is actually necessary.  Three sigma effects come and go in particle physics.

But because of this stringent requirement we are always asking for more.  We always wish for our colliding beams to have a higher luminosity.  We always want the time between crossings of particles in the detector to be minimized.  In short, we always want more data, and there is never enough!

Who knows what is on the horizon of tomorrow’s proton collisions.  I for one have no idea, but I avidly look forward to the coming “more glorious dawn.”

# CPU’s

I’m sure my colleagues have differing opinions on what is and is not needed in high energy physics.  But, I adamantly believe there are two things all of us would agree on.  We always need more data, and we always need more CPU’s.

Cluster computing is the name of the game.  There are rooms at HEP Labs that can usually be heard from “miles away” (or at least a few meters).  They literally hum with activity.  To me it sounds like raw science.  To someone more “normal,” it probably sounds like hundreds of fans all operating at once (which is exactly what it is).  These rooms are filled with racks upon racks of computers, all linked in some fashion.  Users all over the country/world submit hundreds of thousands of “jobs,” or research tasks, to these clusters.  In each of these jobs, a piece of the cluster is given some software a researcher has developed, and use this software to analyze data.

As an example, I perform a relatively small analysis (with respect to the scope of LHC Physics), but I run between 7.5-14K computing jobs a week.  Job number is a bit arbitrary though; this is because a user specifies how large each job is.  To be a bit more concrete, the size of all the data & simulated samples I need for my work is over 80 terabytes.

So how do I, and other physicists, analyze all this data?  With jobs!

And here’s how it works: one of my data sets has roughly 35 million events.  If I attempt to process this data all at once, with one computer (even recent jeopardy champion Watson) it will take forever.  Instead, I break the task of data analysis up into many many tasks (aka jobs).  Each job will analyze 25-50K events.  In this manner high energy physics makes use of “parallel-computing,” and save time.

But why do we need this job system, how long would it really take to process that data in one shot?  Well assuming a spherical cow, each of my jobs takes ~12 hours.  To run over those 35 Million events I mentioned, I need 3836 jobs.  So at 12 hours a job, it would take Watson ~5.3 years to process all the data if it was done in one job.

So much for getting my degree in less then a decade (and heaven forbid I make a mistake!).

But the irony of having so many physicists participating in a HEP experiment, is that not everyone will have all of their jobs running at a time.  Each cluster has a finite number of CPU’s, and a seemingly infinite amount of jobs submitted to it (continually).  What usually happens is a person will have anywhere between 6 to 600 of their jobs running at a time (depending on who else is using the cluster).

So to analyze data, it could take anywhere between a night to a week.  And in this regard, I believe we will never have enough CPU’s.

Until next time,

-Brian

### Night Shift

Wednesday, October 27th, 2010

Bonsoir!

It’s late at night, and here I sit in the control room for the H6B beam line at CERN’s SPS North Area facility. The light is harsh fluorescent, the air is redolent of espresso, and the room is thrumming to the sound of heavy machinery. I am on a night shift.

(An aside: If you thought particle physics stopped for the night — and particle physicists for sleep, ha! — please recall that we have accelerators that create light, and calorimeters that eat light for breakfast. Besides, as a world-spanning collaboration, the sun never sets on our empire.)

There’s a certain charm to working the night shift, or at least a comforting familiarity. One generally follows a similar routine:

[00:00] Arrive a few minutes early and catch up on events from the previous shift(s). Scan through the e-log, then start an entry of your own. Don’t forget timestamps!

[00:15] Follow some sort of start-of-shift checklist. Ensure proper data-taking in spite of your presence. Find the most comfortable chair around and settle in for a long haul.

[01:00] Time for coffee.

[02:00] Continue checking up on the detector at regular intervals, updating the e-log as necessary. Engage yourself with work, or entertain yourself with Internet. Now is a good time to tick items off your to-do-but-not-urgent list.

[03:10] Snap out of a daze that lasted for five minutes.

[03:15] Time for coffee. And lunch.

[04:45] Check email repeatedly in case some industrious person over in the States is still working. Be productive regardless: Your advisor is visiting CERN, and he may appear without warning at any given moment.

[06:00] Enter the night shift doldrums, and despair.

[07:30] Note when the beam shuts off for a planned intervention. Take this opportunity to run a couple of scans on your sensors, if only to break the tedium.

[08:00] Look back on the past eight hours and take pride in the amount of data you’ve helped collect! Finish writing up the shift e-log, make sure the control room is in order, then head home for sleep. Mind that extraneous step in front of your apartment building. Definitely do not trip on it.

Fortunately, this was a smooth and trouble-free night shift during which boredom was the biggest problem faced, but you can imagine how some shifts are made truly terrible: no (stable) beam, sensors failing for mysterious reasons, repeated software crashes, too many emails from industrious people over in the States, the dilemma of whether or not to call an expert at 5am for something that may incite their ire… Clearly, I lucked out tonight.

Oh, one last thing! Be sure to check your work from last night before submitting it for other people’s approval. (Really, “eat light for breakfast”??? It’s staying in, but only as an instructive example.)

— Burton

### CERM Start-up

Thursday, September 18th, 2008

No, that isn’t a typo; I’m talking about the activation of a completely different machine. This one is cheaper, and the practical applications are more obvious, but you can see it doesn’t work quite as quickly as the LHC did:

It has exactly the same probability of destroying the earth that the LHC does.

This excellent video was pointed out to me by someone from the Accelerator and Beams department; his enthusiasm should come as no surprise, because coffee is a major part of the institutional culture here at CERN. We’re powered by it when we’re tired. We drink it when we have informal chats with our colleagues. There are many machines and kinds of coffee to suit all different tastes and nationalities — and yes, you’d better believe there are international coffee issues. For example, if you’re buying coffee and an Italian asks for an espresso, you have to know to buy what the cafeteria coffee machines call a “ristretto” — which apparently just means “small, dense espresso” — because that’s how they make espresso in Italy. As an American, I miss my Venti Double Chip Mocha Frappes, but alas, the coffee machines don’t make those under any name.