HStuckey PHY315/CEB558 Fall 2008
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Impressions of PHY315/CEB558 - Fall 2008 by Harry Stuckey
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September 3, 2008
The session began with Prof. Marx introducing the staff and presenting the introduction to the course. This included some discussion of cosmic rays, fundamental particles, and detection. Students were informed of the obligation to maintain a wiki page and that the first assignment was to set up their page. This was followed by a demonstration of the cloud chamber, which enabled students to observe visible cosmic ray tracks. After that, Dr. Vavilov discussed and demonstrated the MARIACHI detectors. Using a digital oscilloscope, he described the "raw" pulse produced by the photomultiplier tube and the digital pulse that resulted from the raw signal passing through the FPGA. He discussed the idea of coincidence in the detectors and related it to what was visible on the oscilloscope. The concept of detector efficiency was presented, and the class broke up into smaller groups to determine the efficiency of individual detectors. At least one group produced the calibration graph. The entire class will pick up at this point next week.
September 10, 2008
Prof. Marx asked me to do some wiki demos. I prepared a summary of operations that can be found at Wiki Tips. A link to this file can also be found in the "Additional Resources" section of the PHY315/CEB558 course page. I reviewed the student wiki pages and found that about half had completed the assignment, but some seemed to be having trouble with the links and uploading files. I went through quick examples of using most of the buttons on the wiki toolbar. I also showed how to upload files and size images using both Paint and the "thumb" designation in the embedded image format, as seen in the example image in this section. With a thumb, size can be controlled through the "px" value; "right", "left", and "center" can be used to place the image on the page; and a caption can be added. We discussed spacing and tabbing, which does not work the same way as standard word processing programs, like MS WORD. It is probably best to avoid indenting at this stage of wiki construction. Again, it was suggested that students look at other wiki pages in the "edit" mode to see examples of how to perform tasks. My presentation was probably too long, but this was the first time so I wasn't sure of the timing. Next time, it might be better to do a brief wiki intro in Week 1 and then a more advanced discussion in Week 2 after students have had a chance to try some of the skills in Assignment 1.
Since September 10 marked the first beam produced at the LHC, Prof. Marx presented two music videos from CERN. One was a rap on the LHC and the goals of its detectors/experiments. The other was the classic of the Cernettes singing "Collider."
Dr. Vavilov made a short presentation on using Excel. This included importing data and making XY scatter graphs. This would be used in the efficiency exercise, as well as in experiments throughout the semester.
The class then broke into smaller groups to work with the detector apparatus. They again went through the routine for determining detector efficiency. This time, they were asked to make the calibration graph and upload it to their wikis. Following this, they took data sets for several trials at 10 seconds, several at 30 seconds, and one at 300 seconds. Analyzing this data would comprise Assignment 2, which would be emailed and listed on the course page.
September 17, 2008
Dr. Vavilov began with a presentation on error analysis. He included discussion of the Gaussian distribution and what error bars show. Some examples were presented to illustrate the discussion, and placing error bars in Excel was demonstrated. Prof. Marx briefly recapped the lab work so far and talked about the number of counts recorded by the detectors could be changed. This led to the idea of changing detector area. With that, students broke into groups to investigate the effect of moving the middle detector in a three-detector stack to vary area. The goal was to display the relationship graphically and determine a value for flux, bearing in mind teh initially stated value of about 1 particle per minute per square centimeter. Finally, the class reconvened and Prof. Marx led a brainstorming session pertaining to what students could measure with the detectors.
