User:Mwaters01
From MariachiWiki
Michele Waters
Sex: Female
Age: 18
Birthday: November 5, 1988
Hometown: Freeport, NY
Major: Biomedical Engineering
About Me: I enjoy reading fantasy novels, thriller novels, romance novels and fanfiction, watching anime, playing tennis, experimenting... throwing rocks, climbing trees, and taking long bare-footed walks on the beach, at sunset.
Hidden Talent: I can wiggle my nose. Not too much, though, or else it'll fall off.
Favorite Music: Everything... except the music I don't like. And I'm still not too sure about Queen.
Favorite TV Shows: 'House' is all there is, was, and will ever be....
Favorite Movies: See 'Favorite Music.' Except insert the word "movies" where it says "music, " and the words "Clint Eastwood movies" where it says "Queen."
Favorite Books: The Harry Potter Series, Sir Apropos of Nothing, The Importance of Being Ernest, Pride and Prejudice, Bergdorf Blondes, Davinci Code/ Angels and Demons/ Digital Fortress/ Deception Point/ AKA anything Dan Brown, Seventh Tower Series, Sabriel Trilogy, Keys to the Kingdom Series/ AKA Go Garth Nix!, His Dark Materials Trilogy, The Curious Incident of the Dog in the Night-time, Jo Beverly/ Julia Quinn books/ AKA Hurrah for Historical Romances!, 100 Years of Solitude, Neverwhere, And Then There Were None, Murder on the Orient Express, Stephen King books, Perfume, The Wind Done Gone, The Alchemist, Eleven Minutes, The Artemis Fowl Series, Howl's Moving Castle, Confessions of a Shopaholic, Brave New World, and Calculus For Dummies
Future Plans: I'm really excited about the prospect of becoming a Biomedical Engineer. I really enjoy the research aspect of it all... and my dream is to create something marvelous that will revolutionize the entire world! In a good way, of course. My other dream is to write a fantasy novel about the magical adventures of a Biomedical Engineer named Shelly Aguas. I'm not quite sure if I want to go to med school yet, but I'll pave that road when I come to it.
Journal
February 26, 2007
Our first day of class proved to be fascinating. We were immediately immersed in the world of cosmic rays and particle detectors. After a very informative lecture on the many characteristics of cosmic rays, we were taken on a small tour of the lab.
The lab itself, is filled with interesting-looking equipment; some of the equipment we weren’t introduced to, but we did get to look at an old-fashioned Geiger counter and a scintillation detector. We were shown how the detector worked, how an oscilloscope picked up its signals, and we eventually were allowed to play around with the connections, to get a feel for using the machine.
The highlight of the class was the cloud chamber, which is used for detecting particles of ionizing radiation. We were actually able to see the curvy trails left by high energy particles swirling within the mist of the super-cooled vapor at the bottom of the tank.
Overall, the experience was super-cool and quite scintillating!
March 1, 2007
On our second day of lab, we were given a more in-depth explanation of how a scintillator works, and even gained some hands on experience. It was hard going, learning how to properly connect everything in order to get a good signal; for a while we weren't seeing anything at all on the oscilloscope, but we eventually realized that we weren't seeing a signal because it was too small, and needed to be put through an amplifier, first. Finally, we were able to take some data.
As you can see, as we increased the voltage, the rate of counts per second increased. It wasn't surprising that Scintillator 1 had the greatest rate, followed by Scintillator 2, then the Double Rate, (the # of rays per second that passed through both scintillators). Scintillator 1 was situated on top of the second device, exposing more surface area for rays to hit; it was less likely for a ray to pass through both scintillators than it was to pass through only one.
I'm glad to say that I'm not really confused ablout any of the things we did in lab. I think I just need more practice hooking up the machines. I'm excited to know more about the other methods there are for detecting cosmic rays!
March 6, 2007
During our last lab, we were able to use a more efficient method of taking data: the computer was able to record all of the measurements we had taken by hand last week. First, we imported the data from the program to Excel, in order to graph the rate of rays that passed through one scintillator per second vs. trials. We took five rate measurements at ten seconds, and five rate measurements at sixty seconds. Of course, we expected these points to form a straight line; the average number of counts per second should have stayed the same. However, the graph we produced wasn’t quite linear. But it could be seen that the part of the graph taken over the sixty second intervals were more linear; thus we concluded that over longer periods of time, we are able to see a straighter line.
The second part of our experiment involved measuring the efficiency of a scintillator; the basic concept behind measuring the efficiency is that after ascertaining the fact that a ray passed through two scintillators that are strategically placed above and below the third scintillator you are measuring the efficiency of, you know that a ray should have passed through the third scintillator. By dividing the number of rays you received through the third scintillator by the number of rays you received going through both the first and second scintillator, you are able to calculate the efficiency of the third scintillator.
Here you can see that we graphed the efficiency of the scintillator vs. the voltage applied to the scintillator:
This data was taken over sixty second intervals.
As you can see from the graph, the scintillator seems to perform at its highest efficiency when a voltage of 5.7V is applied.
March 8, 2007
During our last session, we spent our time brainstorming, trying to come up with as many ideas as we could for experiments to perform with the scintillators. Kim and I narrowed down our ideas, and chose two:
(1) Where do the majority of cosmic rays come from? above? side? etc.?
Experiment:
- Use hexagon-shaped(!) apparatus to hold the scintillators in place; use two scintillators at a time.
- Place one scintillator in the top slot, and one in the bottom slot; this has the advantage of putting a distance, d, between them, which controls for rays that come at an angle.
- Perform three trials for each position, (scintillators at 180, 45, and 90 degrees), over two minute intervals.
- Graph the number of double counts, (counts that go through both scintillators), vs. their position.
(!) Minor Correction: Stand is actually octagon-shaped.
Question: Can a scintillator detect rays from both sides? If so, why isn’t the count number picked up by the machine doubled?
(2) Does the time of day (morning/afternoon/night) have an affect on the rate of cosmic rays being received every second?
Experiment:
- Place four scintillators side by side on a table, in the center of the room.
- Take average rate (counts/sec) of the four scintillators over two minutes.
- Perform three trials in the morning (9 AM), three at noon (12 PM), and three at night (9 PM), over a period of two days, for a total of eighteen trials.
- Graph Average Rate vs. Time of day.
We’ll probably have to modify when we actually perform this experiment, since we want to take data during class, which starts at 3:50.
Here are some notes and sketches I saved from our brainstorming session:
March 13, 2007
Last time, we began performing one of our experiments. We decided to begin with experiment # 1, since all of the equipment was already set up. We followed the procedure outlined in previous journal, (see March 8), manually turning the octagon stool, so we could use the same two scintillators throughout the experiment. Overall, I believe we received some pretty decent data.
From our data, it can be concluded that most cosmic rays come from either above or below.
March 14, 2007
Yesterday, we tried to expand upon experiment #1 by trying to discover if most of the cosmic rays we were recording were coming from above or below. To do this we hooked up two scintillators, one above the other, putting as much space as we could between them using a lift, in an attempt to control for the direction of the rays. We hooked up a long cord to one scintillator, and a short cord to the other, and fed the lines to an oscilloscope after being put through an amplifier; we did this, anticipating that the signal coming from the scintillator with the longer cord would take longer to reach the oscilloscope than the signal coming from the other scintillator. The theory was that if signal one (with the longer cord) arrived before signal two or right on top of the signal, we'd know that the ray passed through scintillator one first.
We were able to achieve this with minimal results; there wasn't any way to take quantitive data, so we were a bit at a loss as to what we should be recording. By the time the confusion was lifted, it was almost time to go....
However, even with this failure, our next experiment looks promising. Thanks to Dima, one of our guides on our cosmic travels, we will now be able to take the data we need for experiment #2 from home! We can control the lab computer from our own computers to ultimately determine the number of counts/ second as function of the time of day.
March 19, 2007
In our last session, we tried again to determine from what direction most cosmic rays come from, above or below. We set up the scintillators in the same way as last time: two scintillators, one above the other, with a varying amount of space between them between trials. Again, we used the lift to change the distance between them. We hooked up the scintillators to an oscilloscope, triggering on the channel that measured the coincidences of the rays, in order to see both graphs to scale.
The idea is that, you should see the signal from the scintillator that first received a ray before you see the other signal; if a ray came from above, you would see a signal from the top scintillator first.
Below are links to two graphs of the signals: the first graph is of the signals when there is a small distance (0.45 meters) between the scintillators; the second graph is of the signals when there is a large (2.76 meters) distance between the scintillators. The blue line represents the signal from the top scintillator, the yellow line represents the signal from the bottom scintillator, and the green line is the signal coming from both (coincidence).
As you can see from the Voltage vs. Time graphs, the signal from the top scintillator always arrived first. When they were a smaller distance apart from each other, it was slightly hard to tell which signal came first, but when they are farther distance apart, it was easy to see that the ray passed through the top scintillator first. From this experiment, it can be concluded that most cosmic rays come from above.
Experiment #2 is also in progress, (see March 8 entry for full details of experiment); we’ve taken data over a period of two days, and we’re planning on taking more.
March 20, 2007
Today was our last day. We presented our projects in class, and shared our thoughts on each group's experiments. Overall, I thought this class was a great learning experience. I not only learned a lot about cosmic ray particles, but I learned how to design my own experiment. I'll miss being able to have a free reign with such high-tech equipment; not many classes give you that kind of hands-on experience. I only wish we had more time to develop our second experiment, and collect more accurate data.
Thanks to all the professors who helped us get a better understanding of cosmic rays and all of the equipment you use; I'm really glad to have been a part of it!
March 25, 2007
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