User:Ishtihar
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Imran Mohammad Ishtihar (16th September 1987). Born in Bahrain, an archipelego in the Persian Gulf and moved to New York in 2000. Studied Pre-Med at Hillcrest High School located in Queens, New York. He then moved onto studying Physics at City College located in the Manhattan. After completing two years at City College Imran tranferred to Stony Brook University to join its Physics Department. Imran expects to graduate spring of 2009.
email: imran.ishtihar@gmail.com
Contents |
PHY 313 Cosmic Rays
In this class so far we have done experiments detecting cosmic rays. Harry Stuckey once told Imran about an interview between a reporter and Michio Kaku where the reporter asked Kaku about the Large Hadron Collider and the possibility of creating Black Holes. Kaku brushed off this argument by asking about particles of greater speeds bombarding the surface of the earth at a much higher rate than the particles in the collider, referring to cosmic rays.
Day 1
We were introduced to detectors that detect the cosmic rays hitting the detector in the following manner. The cosmic rays hit a plastic panel that is excited and gives off a blue light of very low intensity. To increase this intensity a photo tube is used. This photo tube multiplies the number of photons so for the counter. The counter then tells us how many time this process has taken place. This is a procedure that would accumulate a high error bar so our first experiment was to measure the accuracy of the photo detectors. This is hard because we have no known number of cosmic ray designated for a certain location like the Mariachi lab that we currently conduct our experiments in. So we calculated the efficiency of a cosmic ray detector by place one of the same detector on top and another on the bottom. We began by counting in intervals of 10 seconds. Here is our data.
Day 2
We repeated our trials to get a measurement of even greater accuracy. This was done by increasing the length of the trials. We measured the efficiency of the detector by applying different voltages. To figure out the most optimum voltage is to observe for a specific voltage, the relationship between efficiency and noise. A graph below depicts how efficiency is achieved if we increase voltage but so is the noise.
On the right is the graph of our efficiency measurements. The purple data shows the efficiency increasing as a function of voltage. It is visible that the optimum operational voltage is 5.7V. However the blue data shows the noise increasing as a function of voltage. Therefore our optimum operational voltage is at a section of the graph where efficiency is the highest while noise is the lowest.
Here is the data sheet from day 2
Day 3
This day was really exciting because we learning how much we are able to do with simple cosmic ray detectors. In the experiment we moved out detectors farther out so the area of detection is our variable. We see that as the area of detection increases so does our rate of detection. This is shown in the graph on the right
This graph shows a linear relationship with the area of the detector and the rate of detection. This means a few of things, it shows that the average number of cosmic rays over a small area the detector is almost constant throughout the detector. This is why we get an almost perfect linear graph. It also shows that we are able to control the area of detection.
Day 4 and 5
After the previous discussion about various experimental procedures, we broke up into groups to carry out these experiments. Our group was designated to obtain data of cosmic rays hitting the detectors oriented in different angles. Our data sheet attached below contains the number of times the cosmic rays were detected.
This is the data collected on day 4. Notice how the relation is not linear rather sinusoidal. We took our measurements from 0 degrees to 90 degrees. On day 5 we plan to take measurement from 0 degrees to 180 degrees.
This is our measurement for day 5. Here we see a better graph depicting a sinusoidal relationship. This is because we are measuring flux and flux is a dot product consisting of a multiple of a cosine function.
The following are information that we collected and plan to present in our presentation. Our PowerPoint is uploaded and can be viewed by clicking Here.
For those who cannot upload the file or would rather read the information from the page. Here are the following points that we will be discussing in out presentation.
Our purpose was to determine the relationship between the number of counts on the cosmic ray detector with the angle the detector is positioned.
The reason we have decided to connect the data points while graphing to depict a rate as a function of angle. This also allows us to clearly compare our data with data taken in previous sessions. On day 5 as opposed to day 4, we ran the trial a from 0 degrees to 180 degrees when on Day 4 we ran the trial from 0 degrees to 90 degrees.
As we expected most of the cosmic rays came in at 90 degrees with respect to the horizontal axis. Amazingly for the angles where the cosmic rays had less resistance, had less flux than the ones with greater resistance, as shown by our data.Perhaps the cosmic rays are colliding with particles in the wall to make a larger scattering of particles with less energy, but enough to trigger the double coincidences.
We can carry out more trials to confirm our suspicions about walls creating more cosmic ray scattering. This can be done by also measuring the energy lost by the cosmic rays by using the oscilloscope and measuring the voltage drop. We can also turn the machine with respect to the z-axis to see if the pillar located in the lab, and the concrete reinforced wall would support our thesis.
media:Day4.xls
media:Day5_plot.xls
Day 6
This was the day we presented our experiment to the class. The presentation overall went very well and gave us a good idea about what we can do to improve our data. Our data lacked error bars that are now added on. We discussed possible future experiments that we will be starting the next session. The experiment we plan to carry out is one of taking data by turning our detectors. We will then take data by turning the detectors and rotating it from front all the way to the back. Our previous experiment was done by rotating our detector from right to left.
Day 7 and Day 8
This day we started our experiment. We conducted a few trial at different angles and plotted our results. We are going to continue our trials through day 8 and formulate a graph depicting results from experiments before the presentation and after the presentation. Our data sheet from this day also shown to the right. Keep in mind the graph does not indicate the behavior of the function at which the comic rays are detected. However the graph is within error bars. The next session we completed our readings. Now we have a complete set of data in the following format, this format can be seen in the excel file below listed as Day 8. We have taken our readings in a form that shows the incoming counts as a 3-D image. On the left there is a picture of a sphere showing the rays taken by students in the 2008 summer REU program. We are planning to map the detection of the cosmic rays in a similiar manner.
results from day 7 results from day 8
Day 9
On this day we met up and prepared for our presentation. We have updated our powerpoint to reflect what our new experiments was about. Basically our first experiment dealt with coincidence of cosmic rays with respect to an angle in one direction. For our new experiment we added another dimension to it. Please come to our presentation to find our more about this experiment. a power point is linked Here
