if only the strong force wasn’t so strong…

Hello phyisics fans!

So I have been doing a bunch of cool stuff lately!  First off, last weekend I did my first ‘touristy’ thing and went to visit the nearby town of Marburg.  It was really awesome!  The brothers Grimm lived there for a while and there is a cool castle and stuff like that.

Here’s how it went:  Around 3:30 (I almost wrote 15:30!!) I decided I was bored and it was lame for me to just sit around.  Thus, via train, I was in Marburg at 4:30.  The train system here is amazing!  Then I wandered around for a while, eventually seeing a giant church tower.  I knew Marburg was really famous for the old section of the city, so I walked towards the tower.  It was Elizabethkirke and it was awesome.  I then, following anything old I saw, found the old city.  It was really neat.  The streets were very narrow and it was built on a hill, so the town literally had more steps in its alleys and roads then in its houses!  From here, more exploring yielded several awesome churches, a ton of cool houses, a gigantic castle, a scary dark underground tunnel that I think was left unlocked on accident, and other cool stuff.  It was a fun day, and I got home that night around 11 just in time to go out to a pub with Andreas and one of his friends.  We had some good beer and played some bad pool, so overall it was a pretty good night!

From there I had a very productive week of work.  I have continued working on the FORTRAN program and now it works!!  It is almost done, I have a few little tweeks and things, but overall I got it all working and Andreas said he was surprised at how much I had already accomplished!!  That put me in a pretty good mood…

Also, on thursday we had a presentation of some experimental physicist.  It was actually really boring because he mostly just showed us graphs, then the smart profs would ask crazy questions that he usually didn’t know the answer to.  Whenever he did say anything that could have been interesting it went way over my head.  During the presentation Andreas got out some paper and proceeded to scribble away.  After a few minuets of this, he just walked out of the presentation.  It was really loud and a bit awkward!  Later I went to his office to discover he had solved a problem with his model that I had pointed out earlier.  He was so excited that he had to try it out right then!  He told me there are two types of colloquium, one type is good because it is interesting, and the other type is good because they are so boring that you start thinking about other stuff!

Ok, so I have had one other adventure.  Yesterday me and two of the RISE girls, Jennifer (biologist from Canada) and Elise (biochemist from Alabama) went to a random town in Germany to meet one of Jenifer’s friends from high school who was randomly also in Germany.  We just chose the town that was halfway in between us, and it turned out to be an awesome place!  We climbed a large hill (or small mountain) to get to a giant statue of herkules.  Elise and I dangerously climbed over a spiked fence (that was really high up) to get on to an abandoned aqueduct.  It was super cool.  We also saw a palace and an old awesome castle.  We spent hours walking around the woods to find all these places.

After these adventures, we began to forage for food (look for a restaurant).  We were hungry and tired and wandered the streets until we found a place to eat.  The rest of the day consisted of running across a 6ish lane road, going to an awesome Grimm brothers museum, and randomly finding a festival in the town.  I bought a giant bag of candy.  Then we took a train home.  Overall, it was a good day.

Thus the point becomes, dear reader, America is lame compared to Germany because even a randomly chosen German town has a statue of herkules with 535 steps leading up to him.

Well, I’ll update when I’ve done some more physics or adventuring… until then, have fun!

-Joey

Physics Adventures in Idaho

Hey everybody!

It seems like as good of a time as any to update everyone on my project here. In the very opposite of Joey’s REU, I have been pretty much entirely experimental here in Idaho so far. My project has many stages, and I mentioned that one of the ultimate goals for my project is to help determine a characteristic signature for different fissionable material when they are shot by a linear accelerator. This way, the government can scan more of the industrial shipping crates that come into our ports everyday, helping keep our country safer.

The first aspect of this research is building a pair spectrometer. What is this/what is it used for? Well, the linear accelerator is going to shoot a beam of photons at a converter, which will convert the photon into an electron/positron pair. This converter will be placed right up next to a magnet, so the two particles will move in opposite circular trajectories. After they leave the magnet, they will fly straight into scintillation detectors. Where do I come in?

Well, they have two magnets here. There is a variable B-field electromagnet and a permanent one. The plusses of the electromagnet? It is variable. The upside of the permanent magnet? It doesn’t have a leak in it. My first task was to see if we could use the permanent magnet, whether it would bend the electron/positron pair enough to  avoid each other and the beam. Since it is a permanent magnet, there is a return yoke. So, how much energy do we need to give the electron to clear the yoke. Balance the Lorentz and centripetal forces, use the relativistic energy equation and a ton of nasty trigonometry later, we worked out that the magnet was feasible.

From there, we had to make two scintillation detectors. The was a lot of finding the right parts. A scintillation detector is just a light guide connected to a photomultiplier tube connected to a voltage module. Light hits the light guide, which guides the light (shocker, I know) to the PMT, which sends an electric impulse to an oscilloscope or whatever so we can measure whatever radiation we need. We hooked these up to about 1000V and were able to measure cosmic rays, which I found pretty cool.

For us to gain any useful information from all of this, we need to make sure that our two detectors are collecting data from an electron/positron pair from the same photon. Right now, I am working on these coincidence measurements. We have the two detectors right next to a Sodium-22 source, so we are getting hits  on our detectors more often than the cosmic rays. We send the signals to a constant fraction discriminator, which helps put the two measurements into the same shape. We send both of these signals into another box. This box is a nice “and” or “or” circuit box. It is a lot simpler and nicer than what we had to do in Electronics Lab. We are able to adjust the threshold of each detector, so we are getting hits and not just background noise, and the width of the circuit. Basically, what it takes to generate a signal and then how much time between the two different signals we give it to register them both together and thus activate the and circuit. We are talking in the nanosecond range for these things.

The last part that we need to do for this setup is send the and circuit into a counter. That way we can plateau our detectors. Basically, find the optimum energies to run them at to get the best counts. That will all be done tomorrow. Then we can get into the particle lab and try out this part of the experiment before I move on to my next task. I think that all should make pretty good sense, but feel free to ask any questions.

In other news, I have been making myself feel like a complete wimp lately. I have been running around town and among the hills here lately, and hills can really take it out of you. It has been my goal to finish this 2.3 mile run that ends at the top of this hill. I haven’t made it all the way up the final stretch without stopping yet, but there is always tomorrow. Today, another REU student/my roommate Zac and I went to a local park to participate in their Tuesday/Thursday Open Climb. A very cool guy named Peter taught us how to do figure 8 knots and belay. We both made it up our first wall, but the second proved a little too hard for us, so we both got only halfway. I never knew how much finger strength it took! We tried a third wall, and while it should have been doable, my arms were hurting so much that we called it a day. Next Tuesday, though, I am showing it who is boss.

Later tater haters,

Ian

Physik!

Hey!  This post is actually going to be about the physics im doing, so get ready!

The PhD student that I am paired with, Andreas Fedoseew, has developed a model for the structure of the nucleus that takes into account both quantum and relativistic effects.  Most of my work is writing programs in FORTRAN 90 (thank goodness its not FORTRAN 77) which carry out calculations with this model.  I will then analyze these results and he will take this into account as he modifies the model.  It is a good job, and I really like programming.

My job for the first few days was just to read and learn about the problem.  Andreas mentioned that since we are doing a purely theoretical project, I actually have to understand the Physics to be any sort of help.  I’m going to do my best here to describe the Physics, but I have yet to take quantum and it has been difficult for me to keep up with everything.  Here goes…

The traditional theory of nuclear structure is based on the nonrelativistic many-body Schrodinger equation, but this just isn’t good enough for several reasons.  Under many extreme conditions (such as particles in high density situations) it is important to take other (such as relativistic) effects into consideration.  Also it is important to consider that in quantum mech a vacuum is a dynamical object (because of pair production).  There is growing evidence that learning about these high density and high speed situations will give a lot of insight for the normal situations.  There is obviously a lot more to this… but this is a good summary I think.

Thus, the goal becomes:  Find a relativistic model for the nuclear many-body system (within quantum hadrodynamics(QHD)) where the degrees of freedom are baryons and mesons which is both Lorentz covariant and causal.  So we pretty much would like to make a theory that is like quantum electrodynamics (QED).  There is, of course, a bit of a problem here.  For those of you who remember your QED, it depends on a parameter alpha ~ 1/137.  Since alpha is small it is possible to do some sort of (Taylor i think) expansion in QED.  In QHD the coupling constants are much larger (thats why its called the strong nuclear force and the other is the weak nuclear) so the expansion does not converge.

That is a decent summary of the motivation I think.  From here I examined the Dirac Equation, and the Dirac Hole Theory.  This was a lot of crazy math, but nothing too bad.  I learned that the Dirac Equation provides a Lorentz covariant solution to free particles.  From here, using a little Lagrangian magic, we can end up with several fields which control the interaction of particles.  The particles change the fields and the fields change the particles, and we have several of each… so it is sort of a mess!

In the model we work with we use Mean Field Theory.  This theory is exactly what it sounds like, the field operators are replaced with their expectation values to make everything simpler (but still very complicated overall).  In this process we end up with what is called the effective mass(for each particle), Mstar:

Mstar = M - (coupling constant)(scaler meson field)

As it turns out, once you have Mstar you get everything else for free, chemical potential, baryon pressure, etc…  So we want to get Mstar, but when you solve for it in terms of things we get to know about, it is very very messy.  So that is my job!  Find Mstar, then find everything else.

Mstar depends on an integral which has no analytical solution.  Doesn’t sound so bad yet… but Mstar is also in this integral… which sucks!  Also we use 8 particles and each has two equations (one for Mstar and another for chem pot mu) so that is 16 linked equations which are self-consistency equations(we cant isolate the variable we care about).  To do this we use a program that is a generalization of newtons method for finding zeros (iterating over tangent lines, it is a simple idea that converges very quickly if you have a good starting point) changed to accommodate any number of dimensions which uses a Jacobian instead of a derivative.  This is the program i am optimizing.

The problem with newton’s algorithm is you need a starting point close to the zero in question.  Thus, to find solutions for high temperature we have to solve for T=0 (which is easy), then solve for a small T using the previous solution as a starting point, then work our way up to the T we care about.  This is slow and no fun.  So I have currently been programming the algorithm to decide what step size of T is the maximal possible at each point, so we dont have to do so many points just to get some high T.  it is going well so far.

So for the next few weeks i will be optimizing this program and extending it.  I will also be studying its output and looking for anything interesting.  I am glad that I am so interested in programming, because that has turned out to be my main job here!  Anyway, this is a summary of what physics is going on here.  It isnt very thorough because it is a lot of information, so feel free to ask me if you have any questions!  There is way more I could write but I feel like I have already written too much!

next post will be about my german adventures thus far, i suppose?

have fun!

-joey

Idaho- Famous Potatoes…and awesome Physics

Hey everybody!

This is Ian Noble coming to you straight from the Gem State, Idaho. I am just starting my second week in the program. I am going into my final year at Truman and figured it would be a fantastic experience to spend a summer doing an REU. At the intersection of interesting physics, fun extras, and well paying (it is a 6-way stop apparently) is the REU program at Idaho State University.

This is their first year doing an REU program, so they decided to resolve any doubts by just trying to do more. I have one of the sweetest deals when it comes to money. $4,500 plus free room and board plus full travel reimbursement. The town here, Pocatello, is absolutely stunning. It is larger than Kirksville, but it is quite dead during the summer. Luckily for anyone who likes the great outdoors (like me) this is a perfect place to spend a summer.

I had to get used to the elevation here for the first day or so, because I am definitely not used to being 4,500 feet in the air. There are many large hills and mountains plainly in view from my room. Three of us hiked up a 1,500 foot “hill” on Saturday, and I was glad that I have adjusted to the elevation. We went with a professor’s family and their horses. We even had a neighborhood dog, Abdul, who wanted to tag along. It ended up being about 5 miles when it was all said and done with, but boy was there a view. The sky is so clear here that you feel like you can see forever. We were able to see the Portneuf river, which we will be inner tubing down on July 4th.

There is no end to the beauty of nature here. We are a short trip away from Yellowstone (which they are taking us to pretty soon), 40 miles from Lava Springs (which some of us are doing a bike trip to so we can relax there before heading back), white water rafting, and so many trails to take. I took a run today that ended at the top of the school’s big hill, and that proved to be interesting. I guess I should get more into the physics that I’m doing here though, shouldn’t I?

After touring the facilities, I believe that this school has to be one of the best for nuclear and particle physics research, especially for graduate work. They have 3 linear accelerators (call linacs in the business) ranging from a “pitiful” 20 meVs to 44meVs I believe. They work closely with the Idaho Accelerator Center, which is basically on campus, to do experiments. An hour of beam time here is $2,000/hour I believe they said. They also have a mini nuclear reactor that was especially designed for use in universities to teach students about nuclear physics. It is designed so that it is impossible to go Czernobyl. They are really dedicated to this stuff and giving their students the ability to work with these machines.

I will get into the big details of what I have been working on in my next post, which may happen tomorrow after a big research project meeting we’re having, but I can summarize the concept behind it now. My project’s title is “Linear Accelerator Techniques for Homeland Security and Nonproliferation.” I finally understood what we’re doing about last Wednesday.

There are thousands of shipping crates that are sent into the United States everyday. The big ones that fit on trains and such. Only 2% of them are subjected to random safety checks, so ISU received a grant from the government to investigate if they could work out a way to have a linear accelerator to beam particles into the crates to see if there is any fissionable material in them, increasing our ability to monitor the shipments. So, we need to see if we can find a unique “signature” for different fissionable materials.

I’ll get into my work tomorrow? but until then, enjoy your summers everybody.

Ian

Pre-REU in Buenos Aires, Argentina

¡Hola! I’m Martín Di Stefano, Kirksville native. I just finished my second year in Truman’s physics program (BA) with a (as of now undeclared) math minor with a pre-engineering concentration. I am on track for the 3+2 program and will be leaving Truman after the Spring 2010 semester to continue my education in Aerospace Engineering.

I’m currently in Buenos Aires, Argentina, visiting my extended family. It’s awesome here. This is my sixth or seventh time here (maybe - I’ve lost count), but this place never ceases to amaze me. With all the wonderful food, crazy fútbol games, and beautiful winter weather (70°F), I want to throw away my return plane ticket. On the other hand, I have an exciting summer ahead of me at Los Alamos National Laboratory.

I will be working with Josef Koller at LANL on a project tracing particles through our planet’s magnetic field. So far, I’ve had to do a bit of ‘homework’ before I arrive at LANL on June 1. My first ‘homework’ was to research a bit on numerical methods. I turned this into real homework by making it my topic for the term paper for Math Phys. My second assignment is to read up on the basics of Python. I’m working on that in my spare time here in Buenos Aires.

I don’t have much more to say for now - I think I’ll just go enjoy my final days in Argentina before reluctantly getting on the plane next Wednesday (May 27).

-Martín

Hey all,

Since this is my first post here, I believe a bit of an introduction is in order. My name is Isaac Angert, I’m originally from St. Louis, MO and I’ll be entering my 4th (and final) year of the physics major at Truman State in the fall. I’ll be working this summer with the Laser Interferometer Gravitational-Wave Observatory (LIGO) project at their detector site in southwest Washington State near Richland, WA. Details of LIGO in general: Wikipedia LIGO

LIGO is fundamentally an astrophysics experiment, but the complexity of the apparatus and the difficulties of detecting gravity waves leads to a lot of other interesting research and technological development. Many of the summer REU projects offered in association with LIGO aren’t directly related to gravity waves, but deal instead with the hardware and methods that support the functioning of the interferometer. My project is one of these. I will be working with laser locking, particularly the Pound-Drever-Hall technique. According to my advisor, the work will be mostly hands-on-experimental. I will be working to characterize and test electronics, and other equipment as well as techniques that may potentially be useful for the detector sensativity upgrades that will be done as part of the Advanced LIGO project.

REU’s in general are great experiences, and great fun too. I did an REU last summer at Hope College in Michigan. It was a chance to get a feel for how research works, and it helped seal the deal on my interest in physics as a career. (I can’t fail to mention here that summers in Michigan are really nice, I think it got to 90 degrees just once). Most REU projects pay a stipend and provide room and board, though the exact logistics differ. My housing last summer was subsidized, but we had to buy our own food. Housing this summer has to be paid out of my stipend and again I’ll have to buy my own food. It looks like I’ll have about $4000 (a fortune to a college student) at the end of the program, not counting what I spend on food (and knowing me, this will be a lot).

My REU starts fairly late (the middle of June), so I’m currently visiting my parents in St. Louis, catching up with some old high school buddies, doing some summer reading and preping for a road trip that I’m really looking forward to. I’m planning to drive from Missouri to Washington State, taking about two weeks to drive around the western USA and stop and see the sights.

Isaac

Alles Besser Auf Deutsch!

[this post is pretty long and does not have any physics in it]

Guten Tag!

So I’m Joey Palmer.  I just finished my third year at Truman, I’m a Math and Physics double major with a minor in Computer Science… and right now I’m in Germany.

So why am I in Germany?  Well, for one, Tom Hogan convinced me it would be fun if we both got physics internships here, so I signed up for the RISE program and here I am!  Notice Tom is in Boston (making way more money than me…).

So the rise program is pretty awesome.  You sign up, look at some projects (that grad students here are working on) and see which ones you care about.  Tell RISE the ones you like and in a couple of weeks if you got in then you’re assigned a project.  You get about 650 Euro a month (approx 900 US dollars) and you chill in Europe.  You also get some train passes to go places for free!  The problem is you have to pay for the flight oversees (~$600) and then you have to pay to live here (~$200 per month) and then you’ve got to pay for food.  In the end, you’re lucky if you break even.

So here’ s how its gone so far… The flight was fine, I didn’t sleep much but I watched Paul Blart: Mall Cop in German, which was cool.  I landed in Germany last Friday and the grad student I’m paired with (Andreas) picked me up.  I’ve been here a week and I have yet to be in a car.  We took a train from Frankfurt to Giessen and he showed me where I’d be living.  It’s a pretty okay place, and I get to live by myself, which is nice, although I do have to use a community bathroom (I’m in a dorm).

So I forgot to mention I know very little German!  There is a language course you can take through RISE in Berlin or something… but it costs money and I am already beyond broke.  It’s fine though, almost everyone speaks fluent English, and everyone I’ve met speaks at least a little.  So we’re a little spoiled, but knowing German is not vital to living in Germany.

So he shows me my office (yes I have an office!) and he shows me the break room (and it turns out my office is also the break room…) and I get to meet some people but then I go home to sleep.  So that was a good day.  Also, jetlag is horrible… I went through a 7 hour time shift, so I’m wide awake at 4:00 in my bed and really really tired at 13:00 when I’m at work.  Oh, and for the first few days I had no internet or phone… so that was fun.  So other than a quick call with Andreas’s phone to my parents and girlfriend to say “hey, I’m in Germany and still alive” I had no communication with the outside world.  By Monday I had bought a new phone here and gotten internet in my room, so that was nice.

Now, since Monday I have been working and exploring Giessen a bit.  It is an interesting town.  Apparently it is really old (like older than our country) and used to be a very cultural German town, but then it was bombed all to hell during the war and thus the architechure here is a mixture of old German style and build-quickly-in-the-60s style.  It’s pretty easy to tell which is which…

I see alot of the other people in the Theoretical Physics department here, and they are all really nice.  They have often spoken English around me so I could understand their conversations and they are very okay with me not knowing anything about their culture.  I also met with one of the other RISE students here in Giessen today, we ate lunch and explored a little bit.  It was pretty fun.  Apparently there are nine other RISE students here, and they are all female!  I think the chance of that happening was no so high…

Also, I’ve been spending a lot of time with Andreas, which is pretty cool.  He is a really nice guy.  Last night he took me out around the town and I got to try some German beer and whatnot.  The beer was pretty good, I’m not a big drinker but who could be in Germany for more than a few days and not try some of their beer?  Then later I had some Apfelwine (I’m going to let you translate that on your own) and that was good too.  It tasted a little like I had left apple juice out for to long, and then I realized that is pretty much what it is.  We eat together a lot, and have gone a few places.  So I came into this country not knowing anyone, but now I’ll be able to spend time with the RISE girls and Andreas and the physics crew.  Things are working out well so far!

So yeah, thats the last few days in a nutshell.  Its been interesting to be here and the physics is really cool too (I’m saving that for the next post).  There is a lot more to write… but I am sick of writing and I think this is enough for now.

Auf Wiedersehen!!  (i think thats spelled right…)