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MARIACHI 2008 SUMMER WORKSHOP: July 7-11
QUARKNET 2008 SUMMER WORKSHOP: July 14-18 Blog
Class Syllabus for Hands-on Science with Cosmic Rays PHY315-08
Stony Brook University course PHY315/CEB558.
Week 2 _ February 5, 2008
We spent the beginning of class discussing the efficiency of the cosmic ray detectors. Some of the high lights included:
- How to calculate the efficiency of a detector
- Using two-fold and three-fold event counters
- Optimal operating voltage
After a brief discussion, we divided into small groups and began some hands on experiments using the doctors to determine the efficiency of the particle counts. Lena, Pat and I ran several tests using 3 doctors stacked one on top of the other. We Collected data on Three fold occurrences and correlated them to two fold occurrences (top and bottom detectors). Our rationale was; if the top and bottom detector recorded simultaneous hits at the at the same time a three fold event occurred, and then the middle detector was accurately counting the particle hits. We varied the voltage from 5.1V to 6.0V in 0.1V increments. The sampling time was set to 60 seconds. The results of our work are below.
We found that an operating voltage of roughly 5.75V will yield the best efficiency. A voltage fluctuation of +/- .15V will not affect the results. We also found that as the voltage increased, the efficiency increased until it plateaus at roughly 5.6 volts.
In our second experiment we slid the center detector out from in between the top and bottom detector by 0.25m, 0.5m and 0.75m. As the distance increased, the number of simultaneous occurrences dropped in proportion to the distance moved.
For a view of our data click here
Week 3 Feb 11
Make-up session The weather kept me from traveling to class last week, however, I was able to sit with Dr. Marx the following class and discuss some of the data analysis that we will perform on our experiments. The statistical analyses are based on the counts and the error associated with these counts. The following is a quick summary of the statistics involved:
1) N represents the cosmic ray count
2) The square root of N will give us the absolute error
3) The Square root of N divided by the count will give us the percentage error.
4) The Square root of N divided by the time will give us the rate per second
There are some implications to these analyses
1) The higher the count, the greater the absolute error
2) However, the higher the count, the smaller the percentage error
Conclusion- Larger sample size will yield smaller percent error.
Week 4 Feb 18
At the beginning of class we discussed the larger plan for the Mariachi program. The basic premise assumes the following: 1) The cosmic ray detectors currently employed in the classrooms are a proven and reliable technology. 2) TV signal detectors could be used to identify cosmic ray showers based on the fact that cosmic rays will reflect distant TV signals. This is an unproven technology. 3) The array of cosmic ray detectors in the classrooms around Long Island will be used in conjunction with the TV signal detectors to validate the ability of TV signal detectors to identify cosmic rays. 4) If the TV signal detectors can detect cosmic rays accurately then scientists will have a new tool for studying high energy cosmic rays without the need for large arrays spanning many miles.
Cosmic Chris Experiment.
Our group began experimenting with Cosmic Chris, a portable cosmic ray detector mounted on a dolly with a wood manikin, CHRIS, bolted to the front and back. According do Dr Marx's notes from the first day of class, the cosmic ray rate increases as you move further up in the earth's atmosphere. We decided to test this hypothesis by wheeling Chris around the building and taking measurements on different floors of the building. We used the following protocol while gathering data.
- Chris was laid flat on the ground so that the detector’s large flat surface was parallel to the ground
- We took two counts on each of the following floors D,C,B,A,PL and SL. The highest floor is D and PL represents the ground floor. SL was one story underground and will be referred to as the basement.
- All counts were taken in the stairwell so that all counts were taken in the same vertical 'column'
- Counts lasted for 60 seconds. Time was measured using a hand held stopwatch
- The counter was turned on and off manually.
- One person operated the stop watch and a separate person operated the counter.
The data below indicate that the ray count does in fact increase with altitude. We took an average count on each floor by adding the two counts together and dividing by the total time. This essentially reduced our percentage error and minimized our error bars. We plotted the data on Excel and included error bars for each reading. Please see our results below.
Our data click here
The graph indicates that a direct relationship exists between the altitude and the ray count; however, we need to quantify the height which lies on the x-axis of our charts. We plan to do so next week.
We also plan to investigate the sharp drop in ray count once we headed underground in the same stairwell. We plan to move our testing area to the center of the building next week to reduce the influence that the proximity to the basement walls and surrounding earth may have had on our counts in the basement.
February 25th
In todays class we ran some further experiments using Cosmic Chris. Based on our results from last week pertaining to the counts we received on the SL (basement) floor, we decided to repeat the experiment at different reference points in the building. We collected data on each floor roughly 20 meters from the exterior wall. We believe that the origibnal data collecetd last week in the stairwell was affected by the proximity of the detector to the exterior wall in the basement.
After collecting the data we placed it in Excel and began the process of analysing the numbers using the chi squared function.
The raw data is are posted below:
Media:Rate_versus_height_middle_building.xls
Now we are able to compare the past weeks results with this weeks:
Media:comparing_both_weeks.xls
March 4th
The presentations that we saw today in class helped me to gain a better understanding of what others are doing in class as well as gave me some ideas for future work. I was particularly intereested in the apparatus on the wall of the lab that enabled the user to raise and lower a detector. I would like to try to measure the time it takes for a particle to travel from one detector to another and calculate the particle's velocity. I realize that some work has already been done with this idea, but I would like to take a shot at it.
I was also very impressed with everyone's ability to manipulate data in Excel and use statistical tests. I hope to learn more about using excel and the tools that it offers.
March 11th 2008
We changed our groups this week as people decided to follow different investigations. I teamed up with james and Desiree to begin work on calculating the speed of the particles. We are using the apparatus on the wall which allows us to separate two detectors by a maximum distance of nearly 3 meters. We ran some preliminary tests data which indicate that as the separation distance between two detectors increases, the time between "simultaneous" signals between the two detectors increases. We need to focus on the "simultaneous" aspect of our measurements.
We have not analyzed the data yet and we are still attempting to identify and eliminate the sources of error in the experiment. One factor that we intend to investigate is the length of the cables and the effect it has on the timing of teh signal reception between the detectors and the scope. This signal has a certain speed and associated time. We plan on changing the lengths of our cables and analyzing the time time differences for the signal to travel through the cable.
March 25th 2008
This session started out great when Prof. M pointed out that the slope of our best fit line for the data we gathered was very close to the speed of light, thus indicating that the particles we are measuring are travelling at that speed. This measurement is frought with errors, thus we spent most of the evening honing in on those errors to determine if our initial calculation was accurate. We began by attempting to determine the speed of the signals in the cables travelling from the detectors to the box using direct measurements and then comparinng our values to the published speed. We varied the length of the cables as well as the cable gauge (thickness) Unfortunately, as we approached our very last measurement of the evening, the hard drive crashed on our computer. Very frustrating. We did manage to reproduce some of the data but we lost the majority of it. I will upload our results next week once we have more info.
April 1st
By the end of class today, after dealing with more tech set back, we were finally able to gather some relevent data pertaining to our first experiment. Dima helped us program the scope to grab 130 two fold occurences and dowload teh data into a usable Excel file. We have not yet analyzed that data but hope to use the results to add error bars to our original graph analyzing the speed of the particles. presentation
April 22nd I have been spending the last two classes working with Gillian on her project involving the detectors (and the data that they collect) located in various high schools on Long Island. Gillian helped me to understand the data files that are currently being recorded on our computer at Bay Shore High School. She also helped me to convert the data into an Excel readable file that can be easily manipulated. Thanks for all of your help Gillian.
Since downloading the Bay Shore data I decided to compare the two fold coincidence rates to the Barometric pressure as found on www.uweather.com. The following chart displays that information.
You can access all of my data at the following link.[[Media:|Bay Shore Data]]
Well, I just spent 20 minutes trying to upload that data and it does not wNt to cooperate. I will try it later this afternoon.
In the meantime, Gillian and I plan on comparing her data gathered at Smithtown with my data from Bay Shore. We hope to find a similar pattern in coincidence rates and barometric pressure.
April 29th
SUCCESS! Gillian and I were able to compare our two foild coincidence rates and plot them on the same graph. The following graph is a snap shot of the week dated March 5th 2008.
According to the graph, the time and counts coincide with one another from one school to the next. A general pattern is evident; If the number of counts at Bay Shore increases, the number of counts at Smithtown increases as well. There are two notable locations on the graph however that indicate that "SOMETHING HAPPENED". on the far left of the graph you will note a spike in the rate count at Smithtown that appears to be a short lived event. Gillian and I believe that this must be some sort of computer malfunction based on the raw data.
The other notable exception to the trend occurs on 3/7/08 at Smithtown. It appears that Smithtown records an increase in rate counts over a period of roughly 12 hours that Bay Shore does not record. The spike in counts at Smithtown is notable in its size and duration. If I were to further investigate these results I would try to figure out what happened on that date. If I had to speculate on the possible reason for the prolonged spike in counts I would guess that it was weather related.
In addition to comparing our data, I decided to work on creating a quick download formnat for converting the data files, found on our school's MARIACHI computer, into Excel. The conversion into Excel is tedious and boring for a high school student. If we hope to hook students into the study of particle physics, we need to eliminate the tedious nature of obtaining the data and focus their efforts on processing and analyzing it. I created a download template that quickly converts the date and time stamps into an Excel readable format. Gillian Winters is the one who figured out all of the formulas neccesary to convert the time/date in Excel, without her help I never would have made it this far. Thanks Gillian.Excel Download template. I still need to work out the security on the template. I have been able to write-protect the page and certain cells on it, however, it appears that Excel will not allow teh user to import external data into a protected worksheet, even if some of the cells on that worksheet are not protected. HELP DIMA!!!
You can check out my presentation for this weeks class at the following link. presentation
Our Last week together.
Today in class each student presented their final work in class and we all parted ways. Most students got a lot out of this class. Some fulfilled their goal of simply learning about a new and interesting topic, some fulfilled their degree requirements, some are on the verge of taking it to the next level and some learned about new technologies and software applications.
As for me, I started the course with the hope that I would learn about the scintillators currently installed in my physics classroom and the data that they collect. I am excited to say that after finishing my last project with Gillian, I feel comfortable using the scintillators that we have. I learned how to mine the data stored on our computers and draw comparisons between it and useful weather information. In addition, I now have a better understanding of particle physics and the goal of the MARIACHI program. I feel confident enough to stand in front of my class of physics students and speak intelligently about particle physics. In addition, I feel comfortable leading some of my Scienec Research students towards a project involving the ray detectors. I want to thank Dr. Marx and Dima for all of their help throughout the semester. It was a great class that I will gladly recommend to other science teachers.
bradleykenedy@yahoo.com
