Kristian Harder

thanks everyone for participating, asking questions and voting! It was great fun. Back to normal work for me now. ;-)

Favourite Thing: find problems with electronic equipment. wait, that’s not actually science, is it?



studied Physics with minor Philosophy at Hamburg University, 1993-1998. PhD at Hamburg University and the DESY research institute, 1998-2002


I usually call myself a PhD, but in fact it’s a German doctorate degree, Doktor rer. nat. phy. in experimental physics. Oh, and I also have the corresponding undergraduate degree, which we call Diplom-Physiker

Work History:

Ok, I have been grocery store shelf refiller, gardener, tutor, soldier, programmer, lorry driver. But since this is probably about my career history in physics: for my PhD, I was employed by DESY in Hamburg. Then I worked as postdoc for Kansas State University (go Wildcats!) at Fermilab near Chicago for four years. Then I got hired onto a permanent staff post at Rutherford Lab in England.

Current Job:

I am particle physicist at Rutherford Appleton Laboratory. My current project is the CMS experiment at the Large Hadron Collider at CERN, and those guys are planning to use me full-time for at least the next five years.


Science and Technology Facilities Council.

Me and my work

I work with the largest machine that mankind has ever built, but most of the day I just sit in front of a computer and wonder why my software isn’t working.

In principle my job is quite dramatic. I am one of the scientists working with the largest machine that mankind has ever built,Β the Large Hadron Collider at CERN in Switzerland and France, and try to understand how the universe works.
This job is exciting because it is at the very frontier of science, the most fundamental quest for knowledge, “to boldy go where no man has gone before”.

In practice, the daily work is a bit less exciting, because knowledge comes very slowly, needs a lot (A LOT!) of work to be uncovered, and most of my work is dealing with the practicalities. This means, I don’t spend my day asking myself things such as “would the existence of a second Higgs boson tell us more about how the universe behaved in its first second of existence?”, but rather things like “why does this LED stop blinking if I press this button here?”.

But hey, you’ve got to look at the big picture, and doing that it’s quite a nice job to have. πŸ™‚


My Typical Day

my typical day can look very different in one year than in another, but I can give a few examples.

I am an experimental high energy physicist, and that means I have to do my part in inventing new experiments, designing them down to very technical details, running the actual experiments, and, finally, analysing the data. Because in particle physics experiments are extremely big, extremely complicated, and run for an extremely long time (talking 20 years here!), you tend to do a specific thing for a year or so at a time, and then possibly do something completely different. So, here’s a few of my typical days at work:

2004: Wake up at 3am. Go to the loo. Check on laptop whether the detector is still running fine. All good. Go back to bed. Get phone call at 4am, detector not working, person on shift needs help. Push a few buttons on my laptop. Tell person on shift off for messing it up. Go back to bed. Wake up again at 7am. Get ready, jump into huge car, race to Fermilab, get coffee, go to control room of the experiment, check whether the detector is still running fine. Spend first half of the day discussing a few minor problems with an electronics engineer. Have lunch. Spend second half of the day lying next to the outdoor pool with my laptop, writing software to make monitoring our detector more automatic, so I get more sleep at night. Get coffee. Discuss with senior scientist what priorities we have in fixing minor problems with the detector. Write more software. Go home, get dinner, get back to laptop, write more software. Go to bed.

2007: Wake up at 7am. Get ready. Jump into tiny car, drive to Rutherford Lab. Get coffee. Sit in front of computer all day. Help student to simulate a possible future experiment, to see whether the quality of results with a particular type of detector would be good enough. Disagree. Have meeting with people in Germany, Switzerland, Russia and Japan via phone conference software on laptop. Resolve disagreement. Have coffee. Improve software that simulates possible future experiment. Go home, have dinner, bring children to bed, clean up after children, sleep, repeat.

2010: wake up at 6pm. Get ready. Jump into CERN van, drive to CMS experiment. Have coffee. Have more coffee. Talk to other people to learn how to operate the CMS experiment. Formally take over shift responsibility for the night. Surf the web while waiting for things to go wrong. Nothing going wrong. Sit there for 12 hours trying to kill time. Too tired to do some actual work on the side. Drive back to our work flat near Geneva, go to sleep.

2011: back to getting up at 7am, but now with seven seater car (more children…), but same coffee. Spend all day looking at graphical representations of data derived from Large Hadron Collider collisions. Some crazy (?) theorist had said that there might be a particularly exotic kind of particle might exist that we hadn’t noticed yet because behaves so unusual that our experiments may have simply not seen it because they were mostly tuned for more normal-looking particles. Check with simulation whether we would actually be able to see this. Compare simulation with real data to make sure simulation makes sense. Of course it doesn’t. Try to figure out why. If I look only at particles like this, does the difference go away? If I look at particles only in this part of the detector, does the difference go away? If I compare particles from cosmic rays that accidentally cross our detector with simulated particles, do they look the same? Lots of coffee in between, lots of meetings with status reports on video conference with people interested in similar kinds of things, and even more coffee.Β  Repeat for many weeks. Help graduate student do almost the same thing, but with slightly different particles, to cover more ground.

2013: Same time getting up, same car, same lab, different room. Now spending the day in the basement, in a huge lab filled with electronics. CMS experiment needs to be improved. Several universities develop new electronics to read data from new detectors. New electronics is very complicated. Need people to write firmware (which is something in the middle between writing software and developing electronics), and we formed a team of engineers and physicists to do that at Rutherford Lab. Spending the day sitting in front of a computer (again…), having lots of coffee (again…), and trying to produce firmware that makes our new electronics do what it is supposed to do. Liaise with physicists and engineers in other institutes all over the world, trying to negotiate how to share the work, who is responsible for what, exchanging results, helping each other when things don’t work. Kicking people’s behinds if they fall behind schedule. Being kicked by other people if I fall behind schedule. Wondering why science is so stressful – why can’t we all just sit below a tree and wait for an apple to fall onto our head? πŸ™‚



What I'd do with the money

buy an exotic island and retire :-)

Well, given that’s its probably not going to be enough for buying an exotic island, I had one idea where this amount of money would come in quite handy. Our office+lab building is being refurbished right now, and when done, they want to set up an exhibition area that showcases particle physics. I tried to persuade our senior staff to have projector and chairs in that room as well, so we can not only show visitors around, but also give introductory lectures that explain in a bit more detail what all the items are that are on show. Unfortunately the people in charge told me they won’t have money for a projector in the exhibition area, so maybe that would be a good use of the money? And hey, you all could benefit from it on your next visit to RAL. You *are* planning to visit RAL, aren’t you? πŸ˜‰

My Interview

How would you describe yourself in 3 words?

not. at. all.

Who is your favourite singer or band?

right now, Epica. Check out their album “We will take you with us”! And Anton Bruckner, even though he was a) crazy, and b) neither singer nor band

What's your favourite food?

nothing in particular. I actually don’t care that much about food. if it tastes ok, it’s good enough for me. It is a lot easier for me to tell what food I *don’t* like.

What is the most fun thing you've done?

driving 40 ton trucks through Russia. running obstacle courses during my army days.

What did you want to be after you left school?

either particle physicist or professional soldier. In retrospect, doing particle physics was probably the better choice.

Were you ever in trouble in at school?

never. in fact, I wasted most of my teenage years being the most boring kid in class. no, the second most boring. Olli was worse.

What was your favourite subject at school?

Latin. believe it or not. The only subject I even took voluntary extra hours per week. Ever.

What's the best thing you've done as a scientist?

vacation. And that’s also the rarest thing I’ve ever done as a scientist.

What or who inspired you to become a scientist?

a university textbook about the theory of relativity that I got my hands on as a 10 year old kid. And excellent and very supportive teachers in maths and physics.

If you weren't a scientist, what would you be?


If you had 3 wishes for yourself what would they be? - be honest!

world peace. a much more tolerant society. general happiness. more time. (And I insist, you can have all this with only *three* wishes!)

Tell us a joke.

religion. although sometimes even that isn’t funny.

Other stuff

Work photos:


Above is an aerial view of our machine, the Large Hadron Collider. Well, you can’t actually see it from above because it is some 100 meters underground, but you get an idea of the size. Compare it to Geneva international airport on the right! My, office, whenever I am working in Geneva, is right there in the middle. There. THERE. Don’t see it?



This is a photo of the CMS experiment that I work on. Kinda cool. Even though it wasn’t finished then. Important things: nice choice of colours, and the bright spots, which are actually tags for a laser positioning system. We want to know where each part of our detector is at all times. πŸ™‚



And that is another view of the CMS experiment. See the person for size comparison. The part in the middle was built by my colleagues at Rutherford Lab. I wasn’t here yet when they did that, so my job revolves around other projects.



This is what I am dealing with right now: electronics that is supposed to decide within microseconds whether a particle collision happening in the LHC is interesting enough to be recorded or not. This is a selection of prototype electronics modules to be built into the experiment over the next few years, and my job is to make sure they boot properly, talk to the outside world, cannot accidentally mixed up and so on. Sounds not like science at all, and is definitely more engineering, but it needs to be done, otherwise the science won’t happen! And it’s fun to switch back and forth between various completely different tasks at work.



This is another project I just finished. This is electronics developed by an engineer and myself at RAL, from beginning to end. We came up with this thing to test a series of 16 prototype electronic readout chips (like CCD chips in a digital camera) in a test with an actual particle beam. We had no funding for this project, so we basically did this in our spare time. And it really worked.


This shows a typical situation at work, this time at CERN, where we put the above electronics to use. This is a pseudo “control room” (metal cage) between concrete walls that shield us from the radiation of the particle beams. Lots of people working around the clock to make the test work. As usual, everything goes wrong, and after two weeks of working 20 hours a day (!) it all falls into place within the last eight hours of the test. Yeah.



And after the test, we get to celebrate with a proper dinner at the boss’s home. As you see, this particular project was a collaboration between Chinese, Polish, American, German and Italian scientists, formed pretty much spontaneously because we were interested in this particular thing.



Above: a completely separate part of the job. Teaching! Being a staff scientist at Rutherford Lab, I don’t really have to teach much, but I volunteer as tutor for an annual school for graduate students, where they spend two weeks tucked away in a secret location, being pounded upon by theory professors, and being tutored by semi-clueless experimentalists like me. Great fun, and I also learn a lot.



Or this: trying to explain the general public why we deserve their tax money. The photo is the STFC “LHC on tour” exhibition that tours from place to place. Here we were in a tent at the Bristol Balloon Fiesta. I think I didn’t spend much time with physics that weekend. πŸ™‚ Not sure whether there was more hot air outside or inside the tent.



Oh yeah, and just to prove the geek thing: science is everywhere, even in my cupboard at home. Recognize the Higgs potential there?