Doh...

Sorry I haven't been updating lately. I'm kind of running out of things to do up here while we wait for our room to be built. We've been told "3-4 weeks" several times over the past 3 months and I'm starting to get a bit frustrated. I don't mind doing all this non-science practical stuff, but I really don't want to leave this internship having done zero scientific research. I'm told our room will be built this week... we shall see.

Right now I'm designing a platform to be added on the recirculation cart that will hold a PLC rack (a rack of circuit boards that control solenoid valves and other electrical things), a power supply, and some gray box thing. It's not terribly complicated... I need to design a square board that will be suspended above the cart below via 3 aluminum rods. It's interesting enough to keep my interest for a day or two, but, really, anybody could do this. The good thing is that even if I get out of this internship without doing any real science, I still would have learned a lot. I wouldn't have even considered going back for my Ph.D. had I not come up here, so I'm still thankful I got the position.

I've uploaded a couple of pictures. The picture on the top is the helium recirculation cart while the one on the bottom is the same cart but with our filtration system included.

And now for something completely different!

I was reading a blog post (http://jackbootedliberal.com, check it out!) and in commenting on a certain post I realized how much I'd written! I said to myself "Self, you should post this on your LJ!" So, I am!

Just a note: I don't hate Christians, or anybody for that matter. Please don't think that I do :(

His post was pointing out a hypocrisy in that billboards that say things like "What part of 'Thou shalt not...' did you not understand" --God, are allowed to be put up but if someone puts up a billboard advertising an athiest group's website, then the billboard receives all kinds of media attention and is then usually forced down.

I’ve always disliked billboards like the second one for the reasons you’ve stated as well as my belief that they devalue the religion as a whole. I feel this way anytime I see a sign or bumper sticker that uses some clever-but-not-really pun or "cute" phrase to express one’s belief in Christianity (or any belief, for that matter). I feel that such things degrade what should be a profound and personal set of beliefs and values. Things like this also speak to the commercialization of Christianity, which is also degrading to the religion. T-shirts like “Satan is a NERD”, stickers like “REAL men love Jesus!” Really?On a similar note, I’ve always been puzzled why people need to use things like bracelets, bumper stickers, t-shirts, etc. to express their beliefs. To me, all these things do is apply a label to the person wearing them and they allow themselves to more easily be judged and stereotyped. Is simply believing not enough? Does one need to stand on a soapbox with a megaphone shouting “This is what I believe!” in order to feel secure about themselves? I could speculate forever, but at the end of the day I guess I really just don’t know. I guess this ties into the human desire to feel like one is a part of something greater than oneself.

Perhaps this has to do with the fact that I am wholly against any form of organized, structured belief system. I prefer to build my own belief structure based on my experiences in life as well as by adapting bits and pieces from other structured belief systems. I think that prescribing oneself to a cookie cutter set of ideals (like saying "I'm a democrat through and through!" or "I'm a Romano-Orthodox Latter Day Christian, type B) severely restricts room for personal growth. This ties into my belief that no set of values should be absolute. If one has a conflict between their actions and their values, I believe that changing their values is just a valid an option as changing the actions.

I believe that many people will jump through burning hoops over a pit of lava filled with armored laser sharks instead of doing a bit of introspection and soul searching to resolve their inner conflicts with a set a beliefs that they subscribed themselves to. I think the problem lies in that people decide to live by these values anticipating that they will be the same person X years down the road and then think something is wrong with themselves when that's not the case.

However, I'm fully ready to admit that all of what I've just written is a heap of elephant feces. I'm beginning to think more and more like a certain disco funk communist brother of mine that essentially believes that everything is arbitrary. I'm making conjectures based on nothing but self-anecdotal evidence. I'm beginning to think more and more that it's not that I dislike other people embodying these qualities, but that I'm afraid of myself becoming this artificial "Unhappy Person (TM)" that I've created in my head.

-shrug-

Interlocks

Over the past week or so I've been working on some of the electrical aspects of our experiment. We've decided that instead of having different components run at different voltages, we're going to run all of it at high voltage (around 30,000V). We decided to do this because if you've got one component running at high voltage and another at a much lower voltage, the possibility of a discharge between the two is much higher. Also, if such a discharge were to occur, it could be very dangerous. Ohm's law states that voltage is proportional to current via a constant, resistance. Hence, V = I*R. Assuming a constant resistance, the higher the voltage difference between to points, the higher the current between them. Air is actually a wonderful insulator, but it's just safer (and easier) to hold everything at high voltage.

There is still danger, though. You don't want people running around the the high voltage area while it's running, so we're having to design an interlock and grounding hook system (I think I mentioned this a few posts back? Now for more details!). The power supplies we use have two jumper screws on the back of them. Normally, there's a small wire that connects the two. If they are connected, then the power supply runs. If they're disconnected, it won't turn on. We're going to have a large cage built around the high voltage components and have a system such that if you open one of the three doors a switch will open, which opens the circuit between the jumper screws, and will shut off the high voltage power supply. Essentially, this is three switches in series that are normally closed when the doors are closed.

We've also got to have a way to discharge any latent charge in the components. Enter the grounding hooks! Each door will have a fiberglass rod with a metal hook running through it blocking the door during operation. Each rod is independently connected to a common ground (zero voltage). To enter the room, a door must be opened. Then, the hook has to be removed and then hooked onto a predesignated spot that will discharge any latent charge in the system. Voila! Safety!

I think I've found what I want to do research on during my Ph.D. Dr. Carter is trying to get a collaborative program between Nuclear Engineers and Nuclear Physicists started here at the lab. He wants to do decay heat measurements relevant to nuclear reactors. When a radioactive element decays from one species to the next, there is a significant release of energy (the decay heat). This energy is what's used to power nuclear reactors. Having a better understanding of all the different decay processes will allow better control of those processes which, in turn, allow for more efficient reactors. I talked to a guy at UT who will be working on this project once funding comes in and he was really excited about my background at Tech in physics. He was also excited to hear that I was working on the helium jet. What's awesome is that if I decide to work with this guy I could be using the same helium jet that I helped develop!

There's a problem, though: funding. The group may have funding come September, but there's no guarantee. If there's no funding, then I can't be hired. If I can't get hired, then my tuition isn't waived (which is stupid expensive, being an out of state student). This isn't all bad, though, since I've been told that funding will almost certainly happen... they're just not sure when. I've been assured that I'll have a job here at the lab until the end of the year. I may just have to wait until Spring to start classes if funding comes a little late. No big deal, but I'd rather start sooner than later.

I'm also talking to a few other professors about their research. One guy does measurements pertaining to space radiation protection as well as developing materials that will protect astronauts from this radiation. Another guy does research in nuclear non-proliferation, which essentially means keeping dangerous nuclear technology out of the wrong hands. All three professors are essentially doing applied nuclear physics research and tip-toe the line between nuclear engineering and physics. This just so happens to be the exact sort of thing I'd like to do!

A bunch of Psi U's are going on a cabin trip in the Blue Ridge mountains this weekend and I'm super pumped! It's supposed to be warm and sunny until late Sunday, so plenty of awesome nature things to see.

Idea for a Sci Fi novel?

On a completely ORNL-unrelated note:

I was riding to work today with Jeff listening to Shpongle and I had a great idea for an epic science fiction novel! Many science fiction authors present the idea of ultimate existence as transcending beyond physical existence. Some how humans figure out how to leave their physical bodies behind and become some kind of ethereal energy form that floats the universe for eternity whose only purpose is to learn the secrets of life.

Wouldn't it be totally rad if all of the electromagnetic radiation in the universe was actually other civilizations who have achieved such a transcendence? Assuming the big bang/big crunch model of the universe, what if past civilizations during the last universal cycle formed some sort of ultimate scientific coalition that figured out how to achieve this higher state? What if the only way to cause such a change WOULD BE TO INITIATE THE BIG CRUNCH thereby CAUSING ALL LIFE IN THE UNIVERSE TO TRANSCEND?!

But there's some new threat to the universe... one that could end all life, physical and energy, as we know it. One man (or woman) is chosen by the sum collective consciousness of the universe to stand against this evil. In the end, humanity prevails and the universe is safe. He is presented with a choice at the end of the story to take the ultimate journey into the FINAL FRONTIER... does he accept the offer?

Shit, ida know... somebody write this novel so I can read it. I hereby release this demon of an idea to the world. I wonder if I wrote a letter to one of my favorite epic sci fi authors, Peter F. Hamilton, whether he'd at least read it or not. Man, that guy knows how to write some pretty epic sci fi.

Ok, ok, ok... time to stop spiraling out into infinity and get back to work.

Fon Kaos

That was the password to get into the speakeasy at the prohibition party last weekend. I'm not quite sure what it means (what the hell is "fon"), but that's not really important. What's important is that last weekend was awesome! For a few hours on Saturday it looked like the weekend was going to be complete and utter suckitude, but that changed over the course of half an hour in the early afternoon. I was able to stop moping and get back to celebrating my acceptance into the Ph.D. Nuclear Engineering program at UT.

Oh yeah... I got into grad school! That's such a HUGE confidence boost! I've felt since graduating that I may not have gotten a lot out of my undergraduate education, but both working in the lab and getting accepted to a Ph.D. program has made me at least consider that maybe I know a thing or two about stuff. This is one of the few issues that I'm a bit shaky on when it comes to self-confidence. I'm getting much better about it, though :D

I was really happy with how the prohibition party turned out. The party we used to put on, Heaven and Hell, was essentially focused on making oneself miserable. The External Affairs committee decided to switch things up a bit and they did an excellent job! There was an initial shock when it was announced that the Prohibition party would replace it, but this situation just goes to show that trying new things is awesome! I was also super excited that some of my burner friends came. They're a couple of years older than most of the people there, so I was worried that they wouldn't fit in but that wasn't the case at all. It's always nice to have two separate groups of friends hit it off so well. Those friends have showed myself and other Psi U's good times before and it's nice to know that we can do the same in return.

JJ and I will hopefully start doing further leak testing today. We've got a set of two filters that purify the helium going into our recirculation cart. I was surprised to see that when the Radiation Control Technician (RCT) checked the filters, they were clean of radiation. These filters would be the most contaminated components in our system, however since it's been many years since they were last used whatever radioactivity was there must have decayed.

We've also got to start designing some electricity safety interlocks. Almost the entire helium jet system will be held at around 30,000 volts. Because of this, we've got to have a metal cage around our entire system so that people aren't running around and getting their asses melted by arcing electricity. There will be three doors to get into this area and we need to design an interlock system such that if someone opens one of these doors when the system is turned on, they system will shut down. I would also like to place a bucket of feces above the doors because if someone were to ignore the sign saying something like "IF YOU ENTER DURING OPERATION, YOU WILL EXPLODE" as well as the giant red light, I want them to suffer a bit for shutting our experiment down. I don't think the bucket will end up happening but one can dream, right?

Getting kinda bored

The past two weeks have been "ughhh...", at best. JJ went to India (that's where he's from) for a couple of weeks, so I've been on my own since he left. He left me three things to do: calculate the pressure drop from the argon flowmeter to the ion source chamber, read up on how to operate the turbopump, and leak test the helium recirculation cart. I've got a new value for the pressure drop, but I'm not that confident in the result. I was able to read up on the turbopump, but there's only so much I can do without turning it on. Finally, I was able to leak test a little bit of the cart, but not all of it. I found a really big leak! However, I can't fix it. Because of that, I can't get the background noise of the detector low enough to reliably check the rest of the cart.

What sucks is that I hit all of these roadblocks at the end of his first week away. Last week was really dull since I really couldn't do much. Thankfully, there were a couple of meetings with the nuclear physics group and a student symposium I had to present for, so that took up a bit of my time. I'm glad JJ is getting back so that we can get back to work!

I feel kind of bad that I wasn't able to completely finish everything... however, I've done what I can and I'll just hope that he's pleased. -shrug-

Quantum Physex

I've been trying to solidify my understanding of quantum theory and linear algebra for almost a month now and I've finally gotten it! I was reading Quantum Physics by Gasiorowicz this morning when I read this line: "...we drew attention to the fact that the complete set of eigenfunctions was similar to a set of unit vectors in a vector space, and the expansion theorem was similar to the expansion of an arbitrary vector in terms of unit vectors that span the vector space."

I almost shat a brick. Seriously.

Finally! Once again, months of my physics education clicked in an instant. This statement by itself isn't very complicated, but it's contents are fundamental and deeply profound when things like the uncertainty principle are examined. The uncertainty principle (one version of it, anyway) states that you can't simultaneously know with absolute precision both the position and momentum of a particle. The first reaction to these experimental woes was that somehow the measurement techniques were flawed. When examined from this mathematical perspective, the uncertainty is inherently a part of the system! Now, with just this alone not much can be said. The uncertainty principle could just be a consequence of the model we've constructed, however, there are many other factors involved that have a much more solid physics basis.

All in all, when things like this click in my head I feel as if I've unlocked some new door to the universe. I couldn't focus on much of anything for about half an hour... so profound!

Lab work is going well. I got my Radiological Worker II training, which means I can now work in High Radiation and High Contamination areas. I don't expect to have to do that often, but if I do I know how to put on the crazy radiation suit to do it.

Part of our helium-jet system has a recirculation cart that controls the flow of helium, provides pressure measurements at key points, and also recirculates the helium creating a closed system. Since this cart was shipped in from Canada and hasn't been used in 15 years, we need to test it for leaks. This involves pumping the system to a vacuum and using a leak detector.

The leak detector is essentially a mass spectrometer tuned specifically for helium. You use the detector to pump your system down and use a helium gas cylinder to spray tiny amounts of helium gas over parts you think may be leaking. If any helium gets through, it gets sucked into the detector and it makes this awful beeping noise. I found a pretty huge leak, which is good. However, I can't isolate it from the rest of the system. This is a problem because with such a big leak, I can't get the vacuum to the level I need it at. Because of this, the background noise of the detector can't get low enough for me to detect smaller, albeit problematic, leaks. I'm probably going to have to wait for JJ to get back from India before I can go any further.

I'm also working on a calculation concerning our Argon flow. We have our system set up such that Argon flows out of the flowmeter at a specific rate through about a meter of tubing and into the ion source chamber. Now, the whole reason that things flow is due to pressure differences. Mass flows from areas of high pressure to low pressure. This means that if my Argon is coming out of my flowmeter at a specific rate, but travels through some tubing, there is an additional pressure differential between the flowmeter and the ion source chamber. There is a formula that relates the pressure drop between to reservoirs and the associated flow rate. What I need to figure out is how our output flow rate will be affected by traveling through this tubing via the pressure differential. My problem has been with converting between different types of flow.

The flow that I know isn't actually a mass flow. It's in unites of Joule/second, but it's written as pressure*volume/second. What I need for the formula is volumetric flow rate: volume/second. So I've got to look at a lot of factors when converting between the two, like the relationship between density and pressure/temperature. Since I'm not expecting a huge pressure drop between the flowmeter and the chamber (since our flow rate is so small), I'm going to assume the Argon is at the pressure of the chamber and go from there. Now I just need to find a pressure/density relationship.

I'll be Atlanta inbound about 4 hours from now. Another chapter of my fraternity is visiting, so I'm stoked to see those guys. There's also a party at CoLab on Saturday that I'm really looking forward to. All in all, an exciting weekend awaits!

First shot at Group Theory

Ok, so I've been tossing this around ye olde noggin for a few days now. I've been reading about elementary group theory lately and I've been fascinated by it's implications. I've never really cared too much about abstract mathematics since this. I think the reason why I'm loving it so far is that it isn't buried in obscure jargon (not yet, anyway) and it's core principles are based solely on logic. The very basics of the theory aren't buried in a ton of numbers and odd greek letters.

After reading about a few simple number groups, and a few more abstract logical ones, I've tried to come up with a group concerning the logic of something I see in every day life. I chose how I think I could model the process involved in governing the final temperature of the water as it hits you. I, most appropriately, got this idea while I was in the shower. I'm still trying to work through the details but I think I might have something.

First, how I think the temperature is governed. It's not that big of a deal if this part is way off... what's important is the logic it follows. The idea is if such a system existed, then I would have, in essence, modeled a real-life system in an alarmingly mathematical way.

You have two shower knobs, hot and cold. A few notes about the knobs. There is some number of "ticks" you can make before the knob has gone from fully closed to fully open, i.e. a discreet system. The knob may feel continous, but at the smallest level it could be billions of tiny little steps. Imagine a really loooooong staircase with tiny steps. Anyway, each knob has a certain number of turns. Each knob can only send a single temperature of water to the final spiget. By turning the knob the intensity of the water is increased or decreased. Positive numbers denote hot water intensities and negative numbers denote cold water intensities. If we had a pair of knobs with 3 settings, they would be enumerated like this: -3, -2, -1, 1, 2, 3.

That's just how the water works. I now need to decide my set. My set consist of all possible final temperatures, illustrated as the set of all possible pairs of hot and cold temperatures. I won't list them all, but some possible pairs would be (-2, -2), (-1, 1), (1, -4), etc. The operation would "turning the knob", akin to adding the components of two pairs (-1, 2) + (-1, 1) = (1, 3).

To illustrate the group operation, if I turn the hot knob a lot and the cold knob just a little, the final temperature will be pretty hot, but not quite the hottest it can be. Now, I need to check my 4 rules and this is where I'm a bit iffy.

I'll start with the ones I think I've figured out.

1) Closure under the group operation.

Any combination of knob turns will reside within the realm of possible temperatures (since there are finite turns of each knob).

2) Associativity:

The order in which you turn the knobs doesn't matter. Any hot cold followed by a cold turn is the same were it reversed. -1 + 2 = 2 + -1 = 1

3) Existance of the identity element:

If I simply "do not turn", then the temperature remains unchanged.

4) Existence of the inverse:

Any combination of each knob that's at the same intensity yields the same exact temperature (felt as warm). 3 + -3 = 0.

However, this is wrong. Here's the zinger! I've modeled this system, under all the logic, based on a set of numbers (-3, -2, -1, 1, 2, 3) with the operation of simple addition. If you examine this from a purely mathematical standpoint (dealing with numbers only), the first rule is broken. If you add a positive and negative number that are the same intensity, you get zero. -3 + -3 = 0. The number 0 is NOT part of the original set of numbers, so this proposed group breaks closure and is therefore not a group. What's awesome is that the logical way that I've defined my group (with shower turns, and knobs) also fails BECAUSE they are the same exact group! These two concepts, on the most general level, are exactly the same in that their group tables are identical! The reason they both fail as groups is because there are more possible elements than should be allowed! -3 + -3 = 0; if you never turn the knobs, the temperature is undefined. These two fake-groups are homomorphisms! (I think?)

There are logical fallacies in the other rules, but I won't go into them.

I think I've exhausted my mental power for now. I shall continue to try to find my group.

EDIT: When trying to visualize the "group table", imagine the multiplication tables you saw in elementary schools.

Blah blah

These last two weeks have been rather boring. I've been mostly dealing with logistical stuff and trying to get this order from Matheson in. It's amazing that they make any money given the quality of their customer service. It's up in the air whether someone will ever answer the phone and god forbid I expect them to call or email me back. I wonder if Einstein's progress was ever halted because some bozo salesperson wouldn't call him back?

I've also been reading about something called outgassing. It turns out that when creating a vacuum, getting the molecules in the open air within your volume is the easiest part. The difficult part, then, is getting the molecules (like water vapor) that have absorbed into your surface. Water is a particular notorious substance. To better understand why, it's best to learn how evaporation works.

Evaporation is a process in which a substance in its liquid form transforms to it's gaseous form. Lots of factors effect the rate of evaporation off a surface including surrounding pressure, temperature, surface area, etc. For a water molecule to evaporate off of your head after a shower, it has to acquire enough kinetic energy (i.e., heat transfer) to overcome the tensile forces of the surrounding water molecules. This energy transfer mostly happens due to collisions with other molecules. This is why things dry faster when you heat them up; the extra heat you supply allows more intense collisions to happen which, in turn, allow more molecules to desorb (opposite of absorb) off of the surface. You can also lower the pressure of the surface's surroundings, which lowers the amount of exertion on the surface and lowers the required amount of kinetic energy to escape.

It's the lowering of the pressure of the surface's surroundings that we're interested in. Creating a vacuum is just that process: lowering the pressure in a sealed chamber. As soon as you get to even a modest vacuum, water starts to fly off of these surfaces at a fairly rapid rate. Thankfully, baking your surface at around 150 degrees C solves this problem wonderfully in that it greatly increases the rate of evaporation. Most reasonably sized surfaces can be made acceptably water free in an hour or two.

That is just one example of what is considered outgassing. Other gaseous molecules in the air, like Nitrogen or Argon, can absorb into metals. Baking is the most common method to accelerate outgassing, but there are other methods like electron-stimulation, ion-stimulation, photodesorption, etc. All of these methods use some special process to add kinetic energy to the molecules absorbed on the surface in question and allow them to evaporate off faster.

Star Trek Online is super fun. I'm finally being able to live out my fantasy of being a starship captain. I wish voice recognition software was a few decades ahead of its time so that I could shout "EMERGENCY POWER TO SHIELDS! FIRE A HIGH YIELD PLASMA TORPEDO! HARD TO PORT, HARD TO PORT!" instead of clicking it. Seriously, this game is like a dream come true. Sadly it's interfering with my Mass Effect 2 time (which is also super ballin). At least it will let me stretch the experience out a month or so.

Negative Temperature

Sorry I haven't posted much this week. I've been really busy in and outside of the lab. Negative temperature is something I encountered in my Statistical Mechanics course, but I didn't really understand it until I stumbled upon the wikipedia article on it.

First off, we're dealing with the Kelvin scale. There's nothing special about negative Farenheit or Celsius. Celsius is based off the freezing point of water and Farenheit is based off of... something? The important part is that the Kelvin temperature scale has it's zero as absolute zero. Absolute zero is a theoretical "cold limit" in that no physical system can actually reach this limit. Scientists have gotten to very low temperatures (.004 K is fairly common in condensed matter physics) but none have achieved absolute zero. So, with this in mind, when I say "negative kelvin temperature" you should be thinking something like "Wha...?"

Another aside: Negative temperature is actually a consequence of the definition of temperature and can only occur under a set of certain circumstances. No macroscopic system would ever be able to obtain such a state.

First let's look at the definition of temperature. Temperature is defined as the relationship between the change in energy of a system and the corresponding change in entropy. In calculus speak, T = dq/dS.

The system that we're going to consider is a nuclear spin system, that is a system of nucleons where we are only considering the energy associated with their spins. One caveat of negative temperature is that there must be a finite number of states in the system. For a spin system, that limit is two. A nucleon can either be spin up, or spin down. Nothing else. Also, we are assuming that the spin system is isolated from other sources of energy contribution (i.e., other degrees of freedom like vibrations, rotations, etc). We can make this assumption because the time scale at which this spin system receives energy from these other degrees of freedom is very large compared to the time scale in which we are considering this system. It's like assuming a radioactive element with a half life of 4 billion years won't decay during your experiment that will take 4 hours. Technically, it could decay since the probability for it to decay at each second is equal... but the probability is so low that you can safely ignore it. Now, moving forward...

Now let's say we apply a magnetic field to the system. What this does is break the degeneracy of the system. Before the magnetic field is applied both states of spin-up and spin-down have the same energy. With the magnetic field, those spins that align parallel to the field have a higher energy than the ones that align anti-parallel. Now, the second law of thermodynamics says that a system will evolve over time such that entropy is maximized (order to disorder). How this manifests itself in this system is an even distribution of spin-ups and spin-downs... a 50/50 split.

This is where the magic happens. There are certain techniques that allow you to flip the spin of the nucleons (say, from down to up) by using radio waves. By using these radio waves to move away from the 50/50 split, we are DECREASING the entropy of the system (since the maximum point of entropy is at 50/50) by ADDING energy, thereby creating negative temperature!

An interesting consequence of this is that negative temperature is hotter than positive! Heat will flow from a source of negative temperature to a source of positive temperature. So, the temperature scale goes (from cold to hot) like: 0 to +infinity to -infinity.

Work at the lab is going good. I've probably said this a billion times, but I think we're finally ready to wrap up the gas delivery system. I'll be glad to move on to something else :)

The week is almost over already?!

Time flies when you're doing really cool shit all the time. I'm almost at the end of my third week working at ORNL! It sure doesn't feel that way, though...

My adviser today told me that he's trying to get a collaboration group together that would solely fund research based on the advancement of nuclear energy. Since that's the exact field I'm going into, that was excellent news to hear!

There's just not too much to say today, really. I'm still working on the gas delivery system and we've got three possible solutions. They would all work fine so the deciding factor now will be cost. Some of this equipment is stupid expensive... $1300 for a valve! Granted, it's a SUPER fancy valve that has no detectable leaks down to 10^(-11) torr*liters/second and it was meant to operate in ultra high vacuum... The other mass flow controller we are looking at is $1800! Science is EXPENSIVE!

I'm heading back to Atlanta tomorrow for the weekend, so I'm super excited about that. There's a psytrance show at CoLab on Saturday night, so I'll get to see all my hippy friends and I'll get to spin fire! I'm stoked!

Setback

So, I kind of screwed up. When going over the final design for my gas delivery system to JJ today, he inquired about the accuracy of one of the flowmeters we were planning on buying. The accuracy is rated at +- 5% at the maximum flow rate, which you can pay extra to reduce to +-1%. That accuracy, however, only applies to the maximum flow rate. The further you get from the maximum rate, the worse your accuracy gets. When we calculated the uncertainty at the flow rate we'd be using we got 360% for the +-5% and 76% for the +-1%... both totally and completely unacceptable. Another reason this comes out so poorly is that the resolution of these flowmeters is given in minutes and we need good resolution down to seconds. At least we caught this error before we paid $400 something for the flowmeter. That's one more lesson learned in the world of experimental physics. It's not a huge setback, but it is going to take a few days to find another flowmeter. We're currently looking at electronically controlled ones since I can't find a manual one with the resolution and flow rate that we need.

I started the application process for graduate school on Monday. I sent in the main application (name, birthday, address, etc) and applied to be a Ph.D. student in Nuclear Engineering. I've got my transcripts being mailed to them and I've gotten all the people I need to write my recommendation letters. All I have to do now is wait... Aghhh!

Something interesting about nuclear structure that I read the other day. I'm sure most of you are familiar with the 4 forces that govern what happens in our world: gravity, electromagnetic, nuclear strong, and the nuclear weak forces. The nuclear strong and weak only manifest themselves inside the nucleus, but they are many orders of magnitude more powerful than gravity or the electromagnetic forces. Here's an interesting comparison between the gravitational and electromagnetic force. If the strength of gravity could be represented by the length of my forearm, the strength of the electromagnetic force would be represented as the length of the known universe. That' BIG. Back to the nuclear forces, though...

Here's something crazy I read the other day about nuclear structure. Protons and neutrons are both fermions, which means that in a given energy level no two particles can exist in the same quantum state. Also, within the nucleus, protons and neutrons are much closer together than electrons are which means that collisions between nucleons (protons and neutrons) is a fairly likely event. If a collision occurs, energy is transferred from one particle to the next. This energy transferal would be manifest in one of the nucleons moving up to an excited state (nuclear structure theory has a shell-like model, just like atomic theory and electrons). Now consider some nucleons in the ground state and further consider that there are many filled states above ground. Since all of the states above the ground are filled, if a nucleon were to transition to a higher state it would have to be given enough energy to transition to the very last energy level (like jumping from the bottom step in a staircase to the very top in one jump). What I find wild is that if a collision between two particles would not yield enough energy for such a jump, the particles are not allowed to collide! How #$%@ing wild is that?!

Something like this also happens with superfluids. I can't remember the specifics without looking at my book (which is in Georgia >_> ), but it involves particles being unable to move to excited states because collisions would not provide enough energy (below a critical velocity, in this case). I love physics.

Flat Tire amber ale is delicious.

The Helium-Jet Ion Source pt. 2

So now that we've got a beam of neutral atoms, we need to ionize them. That's where Argon plasma comes into play. Recall that a plasma is a partially ionized gas that has it's electrons on the outside with the ions and neutrals in the center. As this beam of neutral atoms stream in, the electrons strike the neutral atoms causing an electron from the neutral atom to be stripped off, which is called electron impact ionization. The chamber that houses this plasma is also negatively charged. Since the ions we care about are positively charged, they get sucked out of the chamber creating an ion beam! Now, I've skipped a lot of the details, but that's basically how this thing works.

Switching gears. This entire week has been devoted to designing the argon and helium gas delivery systems. Since very little argon is actually used, which means the tank is small and light, we plan on mounting that on a sheet of metal or wood (haven't made our decision yet) along with all the transport lines and a flow regulator. We also want the flow regulator for the helium as well. Since we can't be in the room where all of this is located during the experiment (since the room is being flooded with radiation) we want all of this in a nice, compact design such that we can put a video camera and monitor things from a control room. I've already figured out what components we're going to use, but now I've got to put it all together. I had heard of Google Sketchup, but had never used it before. It's a free 3D modeling program that's good for when you need a simple visualization. I read that it has all the doohickeys and doodads that other 3D CAD software has, but I also hear that it's atrocious for real engineering drawings. Thankfully, I just wanted a rough "sketchup" of the design.

I also got to meet with the rest of my group yesterday. I really only work with JJ and a lot of the other people in the group are in buildings so I'd never met many of these people before. I got to see a seminar on nuclear astrophysics from a potential new hire as well, which was fascinating. I was surprised that I was able to follow as much of the presentation as I did. I guess I did learn something during my undergraduate after all! I also got to network with some people that I could do research with as a grad student later on.

Speaking of grad school... I'm still trying to figure that one out. I'm certain that I want a Ph. D., but I'm trying to decide between nuclear physics and nuclear engineering. I like the idea of helping build things that will pave the way to the future, but I also like the idea of doing the science necessary to build those things. I'm going to be looking into possible programs with the Department of Defense and Department of Homeland Security as well. That's where all the cool classified stuff goes down. Tennessee's state legislature is also voting on a bill right now that will, if passed, provide funding in the hopes of getting more Ph. D. seeking students working at ORNL, specifically those interested in nuclear physics/engineering. That's good for me :D

I hear this pizza place around here called "Big Ed's" is awesome. Pizza being the best thing invented since best things were invented, Jeff, my roommate, and I are going to go check it out. Mmmm.... pizza....

The Helium-Jet Ion Source

I've talked a little about what I've learned and about a few tasks I've finished/I'm currently working on, but I haven't said much about the project I'm working on. So I think I'll do that now!

JJ and I are trying to develop a helium-jet ion source so that we can examine ions of refractory metals. That's a lot of jargon, eh? First off, what is an ion source? Well, it's a source of ions! Ions are atoms that have a charge due to gaining or losing electrons. How do we get these ions, though? There are lots of ways, but our method involves using a Tandem accelerator to send protons to collide with a uranium target that causes proton induced fission. Protons collide with uranium nuclei and break it into two separate, usually radioactive, nuclei.

When something is radioactive, that means that the nucleus is unstable and it must emit something until the nucleus becomes stable. Depending on what is emitted determines what kind of radiation it is: alpha, beta-plus, beta-minus, gamma, etc. Alpha radiation is when a nucleus spontaneously emits 2 protons and 2 neutrons bound together (which actually is the nucleus of a Helium atom) and the original nucleus loses those protons and neutrons. Since an element is defined by how many protons it has, the original nucleus is now a different element! The other types of decay involve protons converting to neutrons, or vice-versa, photons being emitted, and a plethora of other things. The point I'm trying to make is that radiation involves things flying off of radioactive elements.

Back to my project. So these nuclei that are shot off from the uranium target are themselves decaying into other nuclei, which then decay further, etc. etc. What we now have is a ton of different elements flying around. We use an isotope separator to select the specific element we want and then those atoms are shot towards the ion source, which is what I'm working on.

We now have a beam of electrically neutral atoms that we want to turn into ions by stripping them of one or more electrons. Normally, the helium jet isn't needed but it's currently the only way we think we can ionize certain elements called refractory metals. Normally, the beam is directed straight to the ion source, but with refractory metals they end up sticking to the walls of the transport tubes (due to some chemistry that none of us understand).

To fix this problem, we employ the use of a sodium chloride (NaCl) aerosol. Any pressurized spray can (like spray paint) consists of an aerosol inside and this NaCl aerosol relies on the same concept. We then direct the beam through a chamber of the NaCl aerosol, moving the atoms using a stream of helium, and the atoms stick to this aerosol. Since the aerosol + atom clusters are so much heavier than the helium, they all flow in the center of the tube (called laminar flow) and don't bounce around, which means they don't stick to the walls. I'll save what happens next for tomorrow!

I also figured out today our setup for the Argon gas delivery system! We ended up going with the Matheson setup. I'm particularly excited about this part of the project because it's mainly been designed by me. I'd report to JJ every so often and he'd poke and prod me in the right direction, but most of the research has been done by myself. I've learned a lot about how one should go about designing experimental setups and it's really awesome to know that this system will be one of many parts that make this project work. Woo!

Numbers make me cry

My job this week has been working on a delivery system for the Ar-36 gas that will be "plasmatized" (as of now, that is official jargon). I've got to come up with a way to get the gas from a tank into the ion source. It's not as simple as it sounds, unfortunately, and has been quite taxing on my sanity. The difficulty is being able to have this gas come into the ion source at a specific rate of flow, 0.02 std-cc/s specifically.

My first thought was to go to this company called Vacuum Technology Inc. (VTI), who operates in Oak Ridge, and have them design a specific reservoir and capillary leak (that's technical jargon for "tank that spews out gas") that fits our needs. My first calculation turned out to be super wrong when I estimated that given their maximum capacity tank we would only be able to run an experiment for around 14 hours before needing to refill. Since our experiments could run for weeks at a time, this isn't feasible.

I immediately threw that idea out and started looking into their open style capillary leaks, which differ in that you hook them up to your own source. The problem here started with the specs I have to provide to them: pressure coming into the device (known), the rate of flow (known), and the pressure coming out of the device (kind of known). Now, eventually the capillary goes into the ion source which is at vacuum. However, since we are transporting this gas a relatively long distance, there will be a difference in pressure from the exit of the leak to the entrance of the ion source. This pressure drop will affect the flow rate, which means if we want to have a final specific flow rate I need to figure out exactly how much pressure to have them calibrate this device to output.

It's easy, right! Just apply Poiseuille's equation, which relates pressure difference to rate of flow! Well, as I've come to find out, there are two different measures of flow rate: volumetric flow rate (measured in volume/second) and some other flow rate (measured in pressure*volume/second, which actually comes out to Joules/second). Poiseuille's equation uses volumetric flow rate and for most of the day I had been using the other kind. I also ran into numerous problems with determining the exact viscosity of Argon at the conditions we'd have it at as well as a cluster$%@# of unit conversions. Aghhh!

After my problems with the open capillary leak, my boss told me how to actually calculate how long my original plan would work for and it came out to 70 days or so. That's assuming a 1800 psi tank, which is approximately 122 atm, based on some specs I got from VTI. Thinking about it later, 122 atm is retardedly high for pressure so I'm going to have to call back and get those numbers again. Even if we can only squeeze 20 days out of a tank, that would work. Getting the capillary with reservoir calibrated is much easier than the open one so I'm hoping this works out.

I also examined getting one of the huge Argon gas tanks, getting a pressure regulator, and then attaching a flowmeter and adjusting the flow that way. But that wouldn't work because the flow rates possible with their tanks are way higher than what we need! Later I came to find out that I read their rates in std-cc/MINUTE and I was comparing that to std-cc/SECOND. So now that might actually be a viable option! Arghhhh!

The day wasn't wasted... I've learned a bit about how to be more careful with calculations and what not. I'm also that JJ (my boss) didn't get frustrated with me and wa shappy to help me out. I'm going to crunch the numbers again and give him a better report in the morning. Wish me luck? Please?

Plasmas!

These next few posts will be fairly technical in nature, though I'll do my best to not seep them with jargon. However there will be several posts (I've already got them in my head!) that will be chock full of jargon and these will be mainly for my physics friends back home.

I'm going to talk a bit about plasmas, the 4th state of matter. The ions that we're studying are created in plasmas (Ar-36 plasmas, to be exact) and these plasmas are controlled via magnetic fields. Obviously, it seemed to behoove me to understand them at least on a conceptual level. We're all familiar with the solid, liquid, and gas phases of matter. The plasma phase of matter is most closely related to the gas phase in that a plasma is a partially ionized gas. If you reach back to high school chemistry (a disgusting time, I know) you'll recall that an ion is an atom that has an electric charge either by stripping it of one or more electrons (giving it a positive charge) or by adding one or more electrons (giving it a positive charge). Depending on the field of science/engineering that you're working in, a "plasma" could need to be fully ionized (all the atoms are ionized) simply fractionally ionized. I'm not sure on what the True Physics Definition (TM) is, but that's really not important.

How are plasmas created? I'm not sure in general, but I know how we create our Ar-36 plasma: by applying a potential difference between the two surfaces between which the gas inhibits and causing an electric discharge from one surface to the next. In essence, we shock the shit out of it. By giving the gas atoms enough energy, electrons are stripped off the atoms. Where these electrons go and what happens to the ions is what makes plasmas so special. We now have this plum model picture of 3 things floating about: Neutral atoms, positively charge ions, and electrons (the ones stripped from the neutrals). One thing that's awesome about electrically charged things is that we can control them with a magnetic field. By applying a magnetic field with the right geometry and magnitude we can cause the plasma to flow around it's container in a nice, orderly fashion.

This flow has distinct, separate layers. Since the electrons have much lower mass than the ions/neutrals, they flow on the outer most layer (called the plasma boundary) while the ions and neutrals flow within this boundary. Now, due to conservation of charge, the plasma as a whole is electrically neutral, but that doesn't hold true for its constituent parts. With the electrons on the outside and the positive ions on the inside, a potential difference is created. This potential difference is what keeps the inner section inside the barrier. Imagine marbles rolling around in a bowl. To escape the bowl, you'd have to flick them, roll them, or somehow provide them with some external energy to escape the bowl; this is essentially what is happening.

I will go into why plasmas are important to my project in future posts.

First Week

I've finished my first week as an intern at Oak Ridge National Laboratory (ORNL) in Oak Ridge, TN. I'm working with Dr. J. J. Das and Dr. Kennon Carter in the Physics division at the Hollifield Radioactive Ion Beam Facility (HRIBF) on developing a Helium-Jet Ion source. I'll go into the science behind it a bit later. First, a bit of background information.

I graduated from Georgia Tech in December of 2009 with my bachelor's in Physics. I applied to the Science Undergraduate Laboratory Internships (SULI) program, an internship program funded by the Department of Energy (DOE), and was selected for a 4 month internship. There were other people selected as well, though we're all in separate divisions. I ended up rooming with one of them in a nice apartment about 15 minutes from ORNL, Jeff G., and that's been working out wonderfully. All in all, I'm very happy up here. Going to work is a pleasure and something I look forward to and I've learned so much about nuclear physics and ion sources this week.

This first week has mainly been devoted to reading papers on ion sources and basic nuclear physics. Being able to read professionally written papers from Real Scientists (TM) and learn from them is a huge ego boos; it makes me feel as if I actually learned something while I was an undergraduate. Not only am I learning a lot, but I'm enjoying it immensely! I have never found a specific field in physics that I was this excited about. Nuclear physics is @#$%ing awesome! I spent two semesters in Quantum I and Quantum II learning about atomic physics, but I never studied anything about the nucleus of the atom. Learning about how the nucleus works is only one part of our field. All the different types of radiation, how they work, and what data collected about these different types implies is also packaged into this. In this first week, because of this new found fascination, I've been reconsidering what to do with my future.

I'm now considering going back to my original plans of getting a Ph. D. in physics. My biggest reason for changing those plans was that I was both turned off by my undergraduate research experience as well as being unable to find a field of physics that I was excited about. Graduate school for physics is all about specialization and I wasn't able to find something I enjoyed enough to specialize in. Unfortunately, it's too late for me to get into graduate school for physics in 2010. I still haven't taken the Physics GRE as well as getting a bunch of other documents in check.

It's not all bad news, though! Dr. Das has stated several times that he would like to keep me on this project after my internship. If we can figure out a way to make that happen I'm going to stay up here for a while and continue the project. Getting the ion source working is only the first step... after that we could be exploring nuclei that no other human being has ever observed or studied before. How can I say no to that? I can't! If I can stay on here for at least a year I'll have more time to learn as well as getting very good references for my grad school application. I'm looking at the University of Tennessee at Knoxville (UTK) since they have such close ties to ORNL. All of that is a long way off, but I'm trying to get everything in line as soon as I can.

My next few posts will go more into the science of what exactly I'm doing up here. I'll try to make it accessible as possible, but my physics friends would never forgive me if I didn't wank just a little bit using as much jargon as possible, lol.