We placed detectors 0 and 1 together, one on top of the other. 6 The detectors were connected to HyperTerminal (computer program) which read their information every minute. Since we were working with the 5000 Series, we had to manually reset the counter every minute, ON the minute, and input the data into a spreadsheet. We set the voltage of both detectors to 0.60 V; increasing by 0.02 V every minute until we were able to clearly identify a voltage where the paddle(s) plateaued.
7 Our data yielded a plot which made it apparent that our plateau range for Channel 1 was between 0.78 and 0.8 V.
8 A performance study should look something like a normal curve with preferably one peak. Our graph has its highest peak coming from channel 1.
9 We collected data for five days and used that data to do a flux study. A flux study studies the consistency of the events over time. A more stable graph shows the consistency of the data. The graph to the right shows the performance study for the data collected.
10 We ran another data collection session over night in order to conduct a shower study. The paddles were un-stacked so that the coincidence of all 4 paddles would be measured, which would depict a cosmic ray shower.
Lifetime Study 11 We stacked our detectors and let them run overnight. The graph to the right shows the lifetime as detected by our counters. The accepted lifetime of a muon is 2.2 microseconds. We just about hit that nail on the head!
12 To determine whether or not lead sheets could affect the flux of muons. Purpose Research Question Can one millimeter thick sheets of lead affect the flow of muons to Detector #2? Hypothesis Muons will be able to pass through the first three detectors without a problem, but will not be able to penetrate the sheets in order to hit the fourth detector.
14 Technical Responsible for… Setting up all HyperTerminals Saving and uploading Data Capturing Data
15 Physical Responsible for… Adjusting Voltage Checking Counters Keeping track of sheet count
16 Detector 0 Detector 3 Detector 2 Detector 1 Detector 0 is 0.46m above Detector 3 which is 0.25m above Detector 1 which is 1.01m above Detector 2. SHEETS OF LEAD!!
17 After the paddles were stacked, we ran HyperTerminal and told it to only count hits with four-fold coincidence (command: WC 00 3F). We ran HyperTerminal with the same command (WC 00 3F) seven times, once without any lead sheets and the other six times with lead sheets (adding ten each time). Since we are QuarkNet students, our day is planned for us; therefore, we werent able to stop each count at exactly one hour like we had intended. Not being able to stop it exactly when we wanted to wasnt a problem, though. We simply let HyperTerminal do its job and then divided the number of four-fold hits by the amount of time it had been running.
Data 18 Detector 2 average count after one hour with zero sheets: Detector 2 average count after one hour with ten sheets: Detector 2 average count after one hour with twenty sheets: Detector 2 average count after one hour with thirty sheets: Detector 2 average count after one hour with forty sheets: Detector 2 average count after one hour with fifty sheets: Detector 2 average count after one hour with sixty sheets:
Our data shows that the lead sheets did decrease the number of hits that were detected on Detector 2, but not as much as we had hoped. We believe that the lead prevented the slower moving/lower energy muons from passing through and hitting Detector 2. We believe that the reason our numbers didn't continue to go down was because we had enough lead to stop the slower moving muons, but the other simply had too much energy. We concluded that more lead would be needed in order to continue expending the energy of muons so that they don't reach Detector 2. 21
22 During our experiment, we had some trouble with our computer and the program (HyperTerminal) that we were using. The computer actually stopped collecting the data for some reason. We knew that we had gotten significantly more hits than the computer had reported because the DAQs number was much, much larger. So, we had to figure out what the problem was (a cable had come unplugged) and, once we did, we had to run that portion of the experiment over again. Near the end of our experiment, one of the worst possible things happened… eLab stopped working. Luckily, it was only down for a couple of hours, though, so it didnt hurt us too much. The DAQ board is probably the most important piece of hardware in the entire experiment since thats what talks to the computer and puts the data in a form that we can read and use, so when we found not one, but TWO cords that were making the board reset itself, we were worried. We ended up having to tape the cords down so they wouldnt move and reset the board. It was very inconvenient. The shortages were our biggest issue; they cost us a lot of time, but WE PREVAILED!!
23 When we started our experiments, one thing we didnt expect was for our equipment to malfunction, especially not as much as it did. The only errors that could have affected the results of our experiment is if one (or more) or our cables connecting our detectors shorted out and stopped working during the time we were collecting data. Our counts for Detector 2 seem to be consistent throughout the entire experiment, though, so we dont have any reason to believe that any of our counters or cables had shortages during the running of our experiment. We had a lot of noise getting through to Detector 2 before we started our experiment. So much that we had to take it apart and re-seal it. We seemed to have fixed the problem at the time, but since we sealed Detector 2 correctly the first time (or so we thought) maybe its possible that noise may have gotten in during our experiment.
What did we learn? We found that the lead sheets did have some affect on the energy of the muon. The general correlation for the first thirty sheets seemed to be that the more lead that was added, the less hits were detected on the bottom detector. We concluded that number of muons that hit is directly proportional to the number of lead sheets for the first thirty sheets. What is the next step for our experiment? Continue adding sheets of lead and see how many (if its possible) it will take to completely stop the flow of muons to Detector 2. 24