MARIACHI-LAB FINAL REPORT- VERONICA TREADWELL
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Contents |
I. Introduction
Cosmic rays are charged particles that originate from space and intrude on the Earth’s atmosphere. In order to understand the properties of these particles, we composed our own experiments. Using the MARIACHI lab equipment, and staff, we collected and analyzed data that would help us understand the rate of cosmic ray detection versus orientation, that angle with respect to the earth, and the rate of detection versus compass, angle with respect to N, S, E, and W.
II. Methods
Before beginning our experiments we must make sure that all of our equipment is set up and operating properly. First we download the DAQ program into the counter. Open "Mariachi DAQ" folder on the desktop, then go to "Lab-DAQ" subfolder, run (double-click) "Morph-IC Loader.vi" Choose the "Device" "Morph-IC A XXXXXXXX".Click "Program" button, you should see "Status: Programmed OK" We then check that the wires are running from the detector into the proper sockets on the counter. (Run a test run to ensure you didn’t cross the wires anywhere.) In order to test the first part of our experiment we needed to use a special holder:
Rotating the detectors, with respect to the horizontal, we collected data for different angles. Now to test the rate versus compass we follow the same procedures in a & b, but now we rotate the detector with respect to the vertical.
III. Data
FOR RATE vs. ORIENTATION
We first ran the “major” angles: 0, 45, 90 so that we could have an idea where the rest of our data would fall.
We calculate this data using the following formulas
Rate=# of coincidence/total time
Statistical Error=SQRT(# of coincidence)/total time
Graphically:
FOR RATE vs. COMPASS
On our first trial with this experiment, we stood the detectors up vertically and placed them on a scooter, for easy rotation. Our results are as followed:
From this we constructed a graph:
Although this data seemed reasonable, with the way that the detectors were positioned we had no way of differentiating between North and South, or East and West. So in an attempt to eliminate the rays from coming from the opposite direction, we tilted the detectors to 45⁰, with respect to the earth. We then repeated the experiment.
And now our graph looks like this:
IV. Conclusion
Part One: RATE vs. ORIENTATION: We detected the most coincidences when the detectors were at 0 degrees, or directly on top of each other. Although my experiment did no conclude this, we believe this is true because at this angle the rays have less to travel through. It is highly unlikely that the rays would travel through mass of the earth and still get detected, while at angles in between 0 and 90 the rays have to travel through more of the atmosphere.
Part Two: RATE vs. COMPASS: In this experiment, our data shows that in all directions the count is more or less the same, with the exception of the west direction. In another groups presentation we learned that the material between detectors can affect the number of rays detected, so we can attribute the lower count to the west because that’s where the mass of the building is. This data may appear to be conclusive, we feel that in order to obtain more accurate results we must take the detectors out into an open field, where there is nothing to get in the way of detection. In this setting we expect to see some affect of the earth’s magnetic field.
Part Three: Closing Remarks
I enjoyed this lab very much. I liked that we were allowed to pick our own experiments and that it was extremely hands on. We got to not only hear about what we were learning but we got to see for ourselves the affects of numerous things on detection rate. The instructors were very helpful and made the lab that much more worth-while. I look forward to see them again in further physics studies.
