Visualizing signal and noise on channel 7

A spark chamber for detecting cosmic ray showers - look very carefully for the zaps; even though this is 6 floors below ground, we still get cosmic radiation

Today was more test beam time and data collection, this time moving the translation stage for our light sensors up and down and farther back to try to find a full picture of the light projection pattern. The difficult part is that the signal drops significantly when going farther away from the end of the glass bar, so at some point it will be lost in the noise. Vibeke created a plot of distance vs. average signal maximum in volts to evaluate how much light intensity we lose as we get farther away. We learned about background signal and waveform baselines so that we could better extract the signal. 

We also presented for our VIP Sponsor's Day, along with the other 4 teams, meeting diplomats from around the world, sponsors of Beamline for Schools, and directors of the various facilities. We presented our work up until now during a live in-person and Zoom call event. Thanks to everyone who tuned in and supported us from the US!

We had a barbecue banquet reception afterwards with excellent roasted vegetables, cheese, breads, and meats and time to meet with all of the VIP's. There was a massive downpour right at the start of the barbecue, so tables were moved inside to keep everyone dry, and the grill was under a tent. This weather allowed for a beautiful double rainbow on the way back to our guest rooms for the evening. 

Look at the bottom blue line on the oscilloscope reading during this video - those pulses are actually light on a silicon photomultiplier during a test beam run. 

Signals on our central silicon photomultiplier during a test beam

Today was a busy but fruitful day of troubleshooting, productive struggle, and at long last some beam time!

In the morning, the group tackled several tasks. Some of our team worked to prepare the aluminum tube with new 3D printed supports and foam so that we can safely insert the fused Silica glass bar. Ryan continued working on the simulation. Vibeke and others continued to work to understand the data acquisition system.

After lunch,  we had a very educational discussion with Antoine around communication and making sure that all members have at least a basic understanding of what is going on with all the different moving pieces of our experiment. Then we worked to ensure that we could read a trigger from our PCB board. All of our team made accounts and connected to DESY's remote data base. We learned of an issue with our PCB where the high resistance resistors were resulting in no output signal from our SiPMs, and so a kind scientist quickly burned those off for us. We delicately inserted the glass bar into our aluminium tube, set the tube into the blackbox, and were finally able to turn the beam on. Unfortunately, we did not see anything on the oscilliscope. Tomorrow we have the big task of figuring out how to make our SiPMs work, or if not, change our set up and use SiPMs that DESY can provide. Fingers crossed!

This morning, we took the bus and walked through a lovely park to visit European XFEL, the X-ray Free-Electron Laser facility. They partner with DESY to create X-ray lasers, which can explore the structure of matter at incredibly small scales, as well as dynamics of biological molecules. 

There are several different projects happening at XFEL, in fields varying from quantum science to high pressure and temperature environments, and they will even begin to research fusion. We were there until lunch time, when we returned to DESY (after finding some delicious wild blackberries growing along the fence). Today was the first rainy day, with more to come.

Following lunch, we returned to work on various aspects of the experiment. We prepared our black box for the experiment, verified the control system for the translation stages, worked on the simulation, re-designed the holding system for the glass bar within the aluminum tube portion of the black box, connected all the cables from the SiPM board to our digitizer in the black box, connected the power supply, and attempted our first round of data collection of background noise with just the black box and no light signal. 

We discovered our power supply, when set to 40 volts then turned on and connected to our circuit board, dropped voltage to about 15-16 volts. We'll begin tomorrow morning by trouble-shooting the power supply/circuit board setup, but we might know what the problem is already!

In the meantime, the new 3D prints are going overnight (this is a 13-hour job). We've definitely made a habit of re-printing our designs at the end of every day. But we know these ones will be the best so far to effectively hold our glass bar. 

Today is our outing day! We went into the city of Hamburg, with Antoine as our wonderful tour guide, and Oliver accompanied us. We also slept in for the first time all week, leaving at 10:30 AM for a bus to Altona, south of DESY. 

We saw beautiful views of the water while waiting for a water taxi ride towards the Elbphilharmonie Hamburg, where we got to do a 360-tour of the upper terrace with views across the water and into the city. 

We then walked through that part of town towards a modern shopping mall, where Antoine bought us all lunch at a variety of food court restaurants (kebab, Indian food, burgers, etc.). Our friend Henry from the UK team made a Starbucks stop for the Unicorn drink (only available for a very limited time). 

Afterwards, we walked north to get to the St. Nikolai Memorial, where only the tower and a few walls remain from the church that was there until Operation Gomorrah in August 1943, when a large portion of Hamburg was destroyed during air raids. We went midway up the tower, and some of us visited the museum while others rested on a low wall in the courtyard that was once the nave of the church. The memorial is meant to educate visitors on the causes and consequences of WWII, and it serves as an anti-war monument and a place of remembrance. 

Next, we walked towards City Hall, and had free time in small groups around that central part of town. Ms. Becker walked around the small lake with a central fountain, swans, and beautiful views of Hamburg. 

Then we gathered back together in front of City Hall, ordered food, and took the train and bus back to DESY for a pizza party in the cafeteria with just the Beamline for Schools groups. Some of us relaxed outside on the patio while others played pool or darts, basketball, or played piano and sang.  

Today was a long work day at the test beam area. We started by organizing a list of all of the different parts of the experiment we needed to work on, who would do what, and how long we expected it to take. We had so much to do that we were all busy throughout the day without very many breaks, other than for food. 

We got help from Oliver in soldering a super tiny resistor to our circuit board (it is about the size of a small grain of salt). Ryan, Liam, Jack, and Ocean took care of several new 3D prints for stands, holders, and mounts for our various pieces of equipment.

We switched over to a new dark box design with a much, much larger box to allow us to remotely control the position of our detector using 2 motorized translation stages attached together, which were too big to fit in our original dark box for the detector. Instead of our Team USA-themed small ammunition can that was painted inside with "Musou Black"), we now have a giant plastic storage bin with an even bigger, thick black blanket to drape over the whole thing. We'll cut a small, round hole in the back for cables and a larger, square hole in the front for the aluminum square tube that is the black box around our glass radiator bar.

Natalie ran some introductory tests on the SiPM (Silicon Photomultiplier) circuit board with the power supply, and figured out how to correct a ground wiring issue. 

Noah, Levi, and Merlina investigated the cable system with a sample circuit board and made good use of a label maker to number all of the cables that would be connected to the back of our circuit board and to our digitizer to transmit the data from the SiPMs. Jack figured out how the circuit board would need to be spaced from the translation stages and how to arrange the cables so that everything would fit. Ryan has been an MVP, consulting on most aspects of the project and helping out in multiple ways. 

Vibeke and Dylan learned how to work with data readout to the computer using the digitizer and how to set up the triggering system. 

Ryan continued working on his own python code to model the transmission of the light inside our glass bar, and how it would project out the end. 

We also saw the UK team making significant progress on their experiment, so we will hopefully both be ready to test with the beam around the same time. Below are some before/after pictures of their setup. We'll do some before/after of ours once everything is ready!

It gets very hot and stuffy inside Hut 23, so the tunnels from Building 1 are a nice place to cool down, and they provide a quick short cut when going from the cafeteria or meeting room to the test beam hall, useful in the heat or in the rain.

The cafeteria doesn't serve dinner on weekends, so Antoine ordered us all our preferred meals from burger and pizza takeout around 7:30 PM, and we had a picnic dinner outside the beamline while putting one last 3D print job in. We can't emphasize enough how supportive and phenomenal Antoine is for this project and our experience here. 

We started again at 9:00 AM with a quick meeting checking in with our 2 teams at DESY (USA + UK), and the team at ELSA (Bangladesh). The UK team has a very cool experiment using old cell phones as a beam telescope, and their set-up and adjustments are looking good. The Bangladeshi team is testing a new material as a scintillator, which is something that lights up when hit with charged particles. They have already had a beam test with a great image as of this morning! It's also Ms. Becker's birthday. She was surprised with flowers, fresh strawberries, a card from the team, and the happy birthday song. 

We got to work right away at the test beam to move things along with our machinery, circuit board, power supply, and data acquisition system. Antoine, Oliver, and Marcel were all incredibly helpful in troubleshooting whatever issues came up throughout the day. Antoine is putting in a superhuman effort across our 2 teams - he is truly excellent at this work, and we all appreciate him greatly.

The time flew by, but by 7 PM we were all feeling the impact of working long hours. 

After dinner, some of us went to bed early, but a group of us from both teams played basketball together at the court near our guest house. 

At 9:00 AM, we had our first BL4S Whole Group Morning Zoom Meeting with CERN, ELSA, DESY, and all the support staff. Each of the 5 teams from the USA, UK, Türkiye, India, and Bangladesh presented their team and their experimental setup (see the Initial Centauri Stars Presentation Slides), with time for questions. We then received the technical presentations on the beamlines at all 3 facilities. 

After lunch, we visited the test beam hall and had our first work session to prepare for our experiment and get to know the facilities. 

We have been making many 3D prints for parts, testing different components, and getting help from the electronics experts at DESY to assemble the silicon photomultipliers on our circuit board. We also have been working with additional equipment, like a new power supply, oscilloscope, 16-channel digitizer for data acquisition, and connecting cables. 

We have our whole dark box setup ready (and decorated), but we are considering building a bigger one that can house a remote motorized system to adjust the position of our detector.

We tested our custom manufactured quartz bar in the holders we designed, and made sure that light from a laser beam totally internally reflects along the bar.

We worked until about 6:00 PM, returned to the dining hall to play some pool/billiards and to throw darts with the UK team, then we were surprised with a welcome reception and dinner at 6:30 PM hosted by the scientists at DESY, including the assistant director.

Most of the day was safety training, including fire safety and extinguisher practice with a real fire simulator, cybersecurity, cryogenics, and particle accelerator test beam safety. During cryogenic safety training, we also did several classic liquid nitrogen demonstrations, such as shattering roses, shrinking metal pieces and balloons, and making strawberry liquid nitrogen ice cream. 

We also received our official Test Beam User badges and had a tour of the facilities. 

After dinner, we got to go to the top of a new DESY building to view the solar eclipse from the roof. Jorge Andres Villa Velez, the BL4S coordinator from CERN, sent us eclipse glasses. Oliver Schaefer, another excellent support scientist at DESY, set up a projection telescope for everyone to view the eclipse more clearly. 

Some of us got to see some meteors once it was dark, due to the Perseids meteor shower. We successfully survived the first full day with many exciting moments! 

Projection telescope of the solar eclipse with Antoine and Oliver