University of Pennsylvania QuarkNet Center
Submitted by Anonymous (not verified)
on Friday, September 13, 2013 - 09:08
Welcome to the University of Pennsylvania QuarkNet center. We meet on campus and serve teachers in the surrounding area.
Participating teachers will:
- Apply classical physics principles to reduce or explain the observations in data investigations.
- Identify and describe ways that data are organized for determining any patterns that may exist in the data.
- Create, organize and interpret data plots; make claims based on evidence and provide explanations; identify data limitations.
- Develop a plan for taking students from their current level of data use to subsequent levels using activities and/or ideas from the workshop.
We will also provide opportunities to engage in critical dialogue among teaching colleagues about what they learn in the workshop.
Wednesday 3 August 2016
09:30 Coffee, Registration.and Introductions
10:00 Presentation on SNO (Rick Van Berg)
13:15 Level I Data Portfolio Activities
16:00 Reflections; Implementation Discussion
16:15 QN Teacher Survey
16:30 End of day
Thursday 4 August 2016
09:30 Coffee and recap
10:00 ATLAS Virtual Visit
10:30 ATLAS Z-path Measurement
13:00 Discussion and Reflection
13:30 Follow-on to Masterclass
14:30 Implementation plans
15:30 End of workshop
- Preflight checklist for center leaders
- International Masterclasses
- Masterclass Library
- Symphony of Science
- ATLAS Boogie
- ATLAS Virtual Visits
At the beginning of QuarkNet, I knew I wanted to do something with hardware, since Drew from the 2014 program had told me about it. However, when I first began to understand the scintillators, chambers, and electronics, I was shocked at all the learning I had to do. Despite this, I fully feel that on finishing this program, I have learned much more than I intended to.
The first week at QuarkNet seems like a blur in my memory, but I’ll try my best to elaborate. After safety training and a host of other formalities, I began to learn about the equipment and programming with the other students. While my initial date with Verilog did not go very easily, I was determined to understand it more thoroughly. I began studying Verilog and computer logic at home for some time after work, and after a few weeks, I felt that I could understand the Verilog code my peers were doing better. In addition, towards the end of the program, I had to learn elements of Python in order to improve the Raspberry Pi’s data collection method. It felt really good to not just concentrate on hardware throughout the program and instead put on a different hat and continue to learn.
Speaking of hardware, it was the main focus of my experience at QuarkNet. I came in never having taken an electronics course at school, and not even having Electricity and Magnetism in high school physics class. Therefore, many of the hardware topics that were brought up by Mitch, Rick, and others were relatively foreign. Through the process of asking questions and writing their comments down, I was able to understand concepts like grounding, impedance, scintillation, capacitance, and others. After the week 4 progress update, I had a bit of a breakdown when I didn’t think I was learning enough about the electronics and instrumentation to truly understand how the chambers worked. But after consulting with Mitch and Rick, I was able to pay more attention to their comments and learn about the aforementioned concepts in greater detail. Finally, I can’t finish discussing hardware without mentioning my soldering experiences. Although I had experience soldering before with my robotics team, I had never used the technique on such a small scale. After attending soldering school with Godwin, I became more and more versed in the art of soldering our tube wires back together. It was an enjoyable process for me, and I did get to practice a skill that I can now bring back to my robotics team.
Now that I have learned and experienced so much, I feel that I should at least take something away and be able to use those learnings during my daily school life. Other than soldering skills for robotics, I am pleased that the electrical concepts that I learned will help me in my physics course this coming school year. In addition, knowing some new programming languages will help me as we move forward in a technologically diverse world. Thanks to Mitch, Rick, Marc, Steve, Godwin, Walt, and everyone else who made QuarkNet 2015 one of the most enjoyable and interesting summers of my life thus far.
This year we were fortunate enough to have our two High School teachers, Mark Baron and Steve Polgar back with us again who are instrumental in keeping the program organized and maintaining an even day to day flow in our six week program for the selected four (of 16 applicant) student researchers. We started on June 26 and ended on July 31st. Before the program officially started at the end of May we sent each student a copy of The Particle Odyssey by Frank Close to give them a background in the beginnings of experimental sub-atomic physics and also sent links to several references on FPGA programming, a suggestion made by the 2014 Quarknet group to help prepare them for the upcoming work on a cosmic ray tracking tower based on a plastic scintillator trigger and multi-plane Proportional Drift Tube (PDT) array used to provide position data for detected tracks. As usual the students arrived to find a box of parts and no instruction booklet. Most of the tubes are prewired and the front end electronics consists of ASDQ cards re-cycled from the FNAL CDF open tracker. The outputs of the ASDQ cards are sent to a transceiver that translates the differential discriminator outputs from the ASDQ to logic signals sent to a readout FPGA for time of arrival determination and subsequent transfer on to a Raspberry pi computer. As they were constructing the tower and validating the performance of the sensors we provided lectures on sensor signal processing as well as introducing them to physics research underway at Penn through seminars given by professors, post docs and grad students. Once again this immersion research experience was well received our students who, by the end of the program were very close to being able to reconstruct tracks from the cosmic ray triggered PDT hits. This year’s group added LEDs to the FPGA board that were programmed to turn on when a scintillator coincidence was sensed. They were successful in transmitting PDT data from the FPGA to the Raspberry pi microcomputer that they programmed to perform the track fitting. In their own assessment the only reason that they didn’t get to use their track fitting programs on real data was that they decided to start from scratch on the FPGA programming and it took longer than they counted on. In the last week of the program we took a one day trip to Brookhaven National Lab for a tour and met with the QuarkNet students at BNL being mentored by Helio Takai’s group. While at BNL our students took an interest in the long term cosmic ray rate logging experiment being undertaken by the BNL group. We had some discussion about starting a similar effort at Penn but it was close enough to the end of the program that we didn’t really get very far with the idea.
D. Rostovtsev in the first paragraph of his abstract about his QuarkNet experience summed up his experience as follows:
“For me, QuarkNet was a series of firsts. First time learning about cosmic rays, first time using an FPGA, first time using a Raspberry Pi, first time soldering with a microscope, first time seeing scintillators and drift tubes and first time sitting in on lectures in a lecture hall. Also, being a sophomore, it was my first paycheck, first nine to five and first debit card.”
For me, QuarkNet was a series of firsts. First time learning about cosmic rays, first time using an FPGA, first time using a Raspberry Pi, first time soldering with a microscope, first time seeing scintillators and drift tubes and first time sitting in on lectures in a lecture hall. Also, being a sophomore, it was my first paycheck, first nine to five and first debit card.
One of the coolest things we did was visit Brookhaven National Labs. There I saw a real particle detector for the first time. It was incredible how large it was, and it was also incredible how much of the specifics about the scintillators and drift tubes and silicon detectors made sense after learning about them and using them in QuarkNet. The whole experience made me feel like I new a little more than I thought I did before. It closed the gap for me between reading in a book that there are these things I have never seen before called muons and quarks and actually seeing in real life how these things are discovered.
In the lab, I was really happy to find that we gained a ton of specific knowledge and skills with building the detector. The experience was very hands on. I learned how to program in Verilog and I got to build two adapters for the Raspberry Pi in Godwin’s lab. I also got to program a ton in python and learned how to use oscilloscopes, pulsars and NEM crates. So even though we may or may not finish the project, I think that for me, QuarkNet was a great success.
Throughout the six weeks of the QuarkNet program, I worked mostly on the hardware side of the project. The goal was to build a detector that detects and measures cosmic rays. Upon first using the advanced lab equipment, I was introduced to things like scintillators and photomultiplier tubes that I had not known about beforehand. First, we checked for light leaks and found the optimum voltage for each scintillator with a Cesium-137 source. When that was done, we tested the 32 photomultiplier tubes in two chambers to determine which ones were not producing signals. This process took many weeks because some tubes needed to be soldered or replaced. Soldering fixed the tubes that had broken connections to capacitors, and tubes with broken pins or no continuity were replaced. Repeated testing of the tubes was done to determine the ones that produced a signal on the oscilloscope. Some of the tubes gave no signals even when they were fixed or replaced with a working tube. Troubleshooting, such as checking for proper grounding, gas leaks and current draw, was accomplished to ultimately have two fully working chambers. Many of the tubes had to been run at a much higher voltage than originally thought. From the entire hardware process, I got a closer look at electronics and the wiring of the cosmic ray detector. In addition to possessing a deeper understanding of the detectors, I was exposed to the scientific research process. I learned that results don’t just come in ones. Sometimes, we had to go over and redo tests many times, but the end result was always worthwhile. Most importantly, I learned to move on from minor problems when larger unseen issues were looming. I also developed a focused attention for assembling the sensitive instruments and for soldering tiny connections. The patience required for careful handling and fixing of the tubes was an important part of the learning process.
In addition to working on our own project, I was exposed to other areas of physics and astronomy. We attended daily lectures by professors and specialists. The lectures were diverse, from biophysics to gravitational lensing. Furthermore, we attended tours of other labs, including the BLAST lab, the Singh Center for Nanotechnology, the robotics lab, and Brookhaven National Laboratory in New York. It was also very useful to be able to discuss problems and receive help from the University of Pennsylvania staff and faculty throughout the program.
Before I started QuarkNet, I did not know how much I would come to love the kind of work that the people in the High Energy Physics Department do. Throughout the six weeks, I was able to utilize my scientific knowledge and programming skills to work with three other students on a higher level physics project. Having once regarded research as an esoteric process, I was thrilled to discover that research is a means to satisfy one’s curiosity of the surrounding world and to share it with others. The skills and knowledge I have gained at QuarkNet will surely help me in my future endeavors.
Hardware and electronics
D. Ells and N. Zavanelli worked on the assembly of the cosmic ray tower. This included the testing of the proportional drift tubes, making sure that their connections were intact, that the capacitor connections and the ones to the Xilinx Field Programmable Gate Array (FPGA) were functioning as intended. They worked on establishing the optimal voltage for two scintillator paddles, which were used to trigger the detector. The above work involved learning how to solder at the millimeter level, reading the counter instruments, and using an oscilloscope to identify possible cosmic rays. They had to make sure that connections, voltage levels to power sources were appropriately set, and that the high voltage sources for the drift tubes were safely connected and handled. They managed to fix many of the problems with the drift tubes, so that two sets of 16 tubes were functioning so that the detector could track cosmic ray paths in two dimensions.
Software and programming
M. Macerato was responsible for programming the firmware of the Xilinx FPGA, which converted the electrical signals from the drift tubes and provided data for computer analysis. In order to do this he had to learn Verilog, the programming system for the FPGA. Since this differs substantially from programming languages like Java and C++, it was a daunting task even for a talented young programmer like him. But through many frustrating trials, he managed to design a number of alternate versions of the program, each time he ran into obstacles in reading the drift tube signals. In the final version of the program, he designed a counter driven scope-like acquisition of data, based on the FPGA inputs from all the drift tubes for a fixed number of 10 ns clock periods, and had the board send this information to the Raspberry Pi computer for analysis.
D. Grabovsky tackled the computer programming tasks. This involved taking raw data from the FPGA, storing them, and, using a functional algorithm, translating the numbers into a set of cosmic ray tracks. Since there were a number of iterations of the Verilog program for the FPGA, he had to rewrite his program for the Raspberry Pi each time. He succeeded because of his thorough understanding of the Math and the programming requirements.
The students were disappointed that they did not have enough time to identify cosmic tracks and to analyze these, in spite of the clear signals obtained from the drift tubes, but they certainly left with a much clearer idea of how experiments work in a physics laboratory. They had a thorough introduction into the complex and cumulative nature of cosmic ray detection and analysis.
Summary of the Penn 2014 QuarkNet Program
This year we had an exceptional crew of High School researchers: N. Zavanelli, D. Ells, M. Macerato and D. Grabovsky. They came to us armed with curiosity and tons of expectation pursuing High Energy Physics along lines that they had learned about in high school physics courses, physics club and on the internet: primarily Particle theory and Quantum physics principles. They seemed a bit taken back when looking at pile of equipment they would use to make real world measurements of sub-atomic particles. The connections to theory and basic science weren't so clear at least for a while. As they learned about the program through daily seminars and about the work in Experimental High Energy Physics going on at Penn, their enthusiasm grew. They seemed especially pleased by our concept that the QuarkNet project is a multi-year development where year by year student researchers sophisticate a Cosmic Ray tower that has been built, rebuilt and improved over the past 7 years. The students start by re-assembling the basic components according to documentation archived by QuarkNet groups from previous years and become familiar with the apparatus. The Cosmic Ray Tower includes two scintillator paddles to establish a readout coincidence reference time, 64 proportional drift tubes housed in 4 - 16 tube planes with readout electronics designed at Penn for use in CDF and Data Acquisition elements very similar to what is used in high energy physics experiments: An Xilinx FPGA coded for readout by the students that feeds data to a Raspberry Pi computer with resident track re construction programs again written by the students themselves.
They are initially given the job of reading and evaluating the documentation written by students in previous years that describes the equipment left to them and using it as reference documentation to understand how to re-assemble the cosmic ray tower and calibrate the operating voltages and thresholds. As they go they are encouraged to re-write the descriptions as part of their archive for the following year. This year's group felt they didn't have enough pictures of the assembled equipment, and that the FPGA code they inherited could be written with more comments and in a different way. They responded by leaving a relatively complete description of their setup with detailed pictures and descriptions. They gave us three presentations at two week intervals and were encouraged to pose questions to us and themselves about the equipment and completion strategies to get to something reading out if not the whole system. They were collaborative, self-organized and accomplished a lot on their own. Along the way developed a deep appreciation of how to write FPGA code, validate the signals from proportional drift tubes, set front end electronics thresholds and write Python code to deal with the data as it arrived.
Towards the end of the program we went on a field trip to Brookhaven National Laboratory where Helio Takai took us on a guided tour. We visited the BNL Instrumentation group where Paul O'Connor led the tour and then went for a guided tour of the Star Detector. We returned late in the evening with time for plenty of discussion during the three hour ride each way.
Finally they have left us with a short presentation to be sent to next year's QuarkNet students in advance of the start of the program to give them a head start on the project.
I was most impressed by their adaptability in all forms during the program, leaving old expectations behind and allowing new ideas and simple realities focus their work. Most interesting was a complete change in the way that data was acquired by the FPGA code and sent to the Raspberry Pi. With some encouragement from us, they went from a simple leading edge initiated timing readout to a counter driven scope like acquisition reporting the state of the FPGA inputs from all tubes for a fixed number of 10ns system clock periods. This time sequenced array of 0's and 1's provided a way to find the arrival of the earliest signals from the drift tubes without having to know (with significant precision) when to expect them. This approach required reprogramming the FPGA and the Raspberry Pi and was written exclusively by them in the last three days of the QuarkNet program and it worked! While no time was left for physics analysis, they were able to get sensible signals from the drift tubes and left ideas for the next year's students to carry on. You may notice in their comments that there wasn’t enough time to make the Cosmic Ray Tower perform its expected track finding function, but all in all this year’s program was a great success.