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Quarknet 2011: Students: N. Tarshish, S. Mc. Namara, B. Goldblatt, P. Suganthan Teachers: M. Baron, S. Polgar Note: some graphics taken from 2008 Quarknet site
What does CREAM Stand for? Cosmic Ray Exposed Acquisition system of Muon track data that is later interpreted analyzed at Quarknet 2011, a summer program for high school students at UPENN.
Goals Set up hardware so that cosmic rays trigger scintillators and detect the rays’ paths through chambers, which contain sets of 32 proportional drift tubes Create a program to analyze data from the drift tubes Determine, graph, and store equations of the muon tracks.
Muon Tracking Process Abbreviated Primary cosmic ray strikes Earth’s atmosphere SAD PUTIN
Capturing The Cosmic Track Primary cosmic ray strikes Earth’s atmosphere INVERSE CIA/KGB RELATIONSHIP SAD PUTIN
The Apparatus Photomultiplier Tubes Scintillators
Scintillators The scintillators’ signals are sent first to the discriminator and then to the logic unit. If the logic unit finds a coincidence, it sends a trigger signal to the Xilinx chips. Upon receiving a trigger signal, the Verilog captures data from the proportional drift tubes. Problems: Checking for light leaks Finding the optimal running voltages Making sure we received coincident signals At the beginning of the project, we swept through different voltages in order to find a voltage, at which we could be confident that we were detecting the presence of muons and not noise interference. Midway through the program, the top scintillator began reporting thousands of more events per second than was expected. This impelled us to identify a new voltage that yielded stable results.
Proportional Drift Tubes Photo Drift Tubes (PDTs) detected muons and sent signals to the ASD-Q and Xilinx chips Problems: Finding the optimal running voltages for the tubes Getting a proper ground to reduce noise Finding broken tubes and documenting malfunctions
Drift Tube Problems Several of the tubes were not connected to the ASD chips and many of the connections needed to be fixed. A handful of constantly firing tubes needed to be grounded. Thresholds had to be reestablished after the faulty tubes were removed. In the end, since we had too many faulty tubes in chambers one and two and not enough time to fix them, the two chambers had to be abandoned.
ASD-Q Chip This chip amplified, shaped, and discriminated “raw” signals from the drift tubes. These signals were then sent to the Verilog program in the Xilinx chip. Problems: Reducing noise through making better grounds Finding the optimal threshold for the chips
Verilog/Labview/Java We inherited past years’ Labview and Verilog programs. Slight modifications were made to the Verilog program to correct a few errors in the code. Isaac also threw together a Java program to convert Labview’s unstructured hex output into a structured decimal data file. Nathaniel and Ben further developed the program to match the C++ program’s needs.
C++ Program A major component of this year’s project was the development of a program to analyze the data C++ was selected because it was the only language that Nathaniel was familiar with. The program takes in the Java program’s data txt file and outputs the graphs of the muons and the respective time circles that the track is tangent to. The program successfully identifies tracks, but defines a limited solid angle. Therefore, only a small subset of the data matches the parameters set by the program. Also, the program currently finds the path of the muon in only two dimensions due to the lack of functional tubes in the ZY plane.
Data Analysis Mathematics We developed a method for finding a generalized common tangent line for any four possible timing circles. We had to design the mathematical solutions so that they were programmable. We learned much about the subtleties and faults of our system during this stage of the project.
Final Analysis Over the last few days, we have been collecting data. Unfortunately, the majority of the events involved fewer than four tubes firing and therefore the C++ program was not applicable. Some of the events involving three or more tubes appeared to be useable. While the coincidence times did not fit our expectations, the geometry of the tubes registering the events did.
Future Quarknet Goals Identify and fix all problematic tubes Increase solid angle Generate a 3 -dimensional graph of the muon paths Create other data analysis programs, which are based on tube firing frequency, the statistical distribution of the tracks, etc. Begin running gas through the tubes and set up hardware as soon as possible
Other Unrelated Discoveries Particle accelerator or Death Star weapon? Steve sleeps in various positions :
Highlights “So why do they pay for this? ” – Ben Goldblatt, asking Professor Williams mid-talk. “Look! I put the faculty to sleep!” – Professor Devlin after noticing Mr. Polgar sleeping during his lecture. He then proceeded to shine the laser pointer on Mr. Polgar’s belly. “I have this incredible urge to feel Rick’s beard. ”Anonymous Polgart – the concoction of yogurt-drowned unidentifiable breakfast foods that Mr. Polgar daily consumes.