A decade of effort has led to Texas Tech playing an important role contributing to international particle physics community.

Years of work establishing a significant presence in the international scientific community came to fruition recently as Texas Tech University’s Department of Physics & Astronomy completed its first portion of a shipment of production detector modules.

The first 78 modules represent an important milestone and were sent to the Fermi National Accelerator Laboratory in Illinois. They will be used in a next-generation calorimeter being built to upgrade the Compact Muon Solenoid (CMS) detector at CERN’s (European Council for Nuclear Research) Large Hadron Collider (LHC) in Geneva, Switzerland.

“This work has been in motion for the better part of a decade,” said Chris Madrid, assistant professor of high energy physics, within the College of Arts & Sciences. “And it has reached this point where we’ve produced modules that will go into the main detector.”

Texas Tech’s High Energy Physics group has played an active role in international particle physics research for more than two decades.

The group has grown over the years and includes five faculty members: Nural Akchurin, Sung-Won Lee, Igor Volobouev, Yongbin Feng and Madrid. Their research spans searches for new fundamental particles, precision studies of the Higgs, W and Z bosons and the development of advanced particle detector technologies.

The group contributed to the discovery of the Higgs boson in 2012 and has since taken on a major role in preparing CMS for its next generation of experiments. The detector modules were produced at Texas Tech’s Advanced Particle Detector Laboratory.

In addition to Madrid, the module production effort has been co-led by Akchurin, professor of physics, with support from departmental staff members Kirsten Cowling, Xander Delashaw, Savannah Randall and Sonaina Undleeb in addition to students assisting with module production, quality control, testing and shipment preparation.

“This is a major milestone for Texas Tech University and our Department of Physics & Astronomy,” said Lee, professor, department chair and a senior member of the High Energy Physics Group and the CMS collaboration at CERN. “After nearly a decade of dedicated research, development and teamwork, our team has successfully produced and delivered these state-of-the-art detector modules for one of the world’s most sophisticated and ambitious international particle physics experiments.”

The CMS detector project has had an ongoing presence in the physics world for almost 15 years, dating back to the Higgs boson discovery in 2012 that was a major breakthrough in identifying new particles and opening additional avenues of scientific inquiry and exploration. 

Starting in 2030, the LHC will move into the high-luminosity era, where CMS needs to capture even more data even quicker than before.

“The detector was built in the early 2000s,” Madrid said, “and there have been some improvements to technology since then. As we have moved into this high-luminosity era, we wanted to remove and upgrade certain major aspects of the detector. Basically, we will remove the nose, which is about the size of a minivan, and replace it.

“Our goal now in this lab is to produce the sensing electronics and detectors for the new upgrade.”

Now that the first shipment has taken place, Texas Tech expects subsequent deliveries to number in the hundreds.

Texas Tech’s part of the project is to build 5,000 modules, which are made primarily of silicon and are extremely fragile. They are carefully assembled by a specialized team with advanced equipment in the lab’s clean room. The modules have to function properly at temperatures of minus-40 degrees Celsius and go through rigorous testing before they can leave the lab. 

The process involves using eight-inch, wafer-based sensors and placing them into the modules before they are wire-bonded and tested to make sure they function properly. From Texas Tech, they are shipped to Fermilab, where they are assembled into the larger component that will then be shipped to and placed in the detector at CERN.

“At Fermilab, they will take all of the modules and put them together into what will look like a pizza shape,” Madrid said. “Each module is a hexagon, and they all fit nicely together.

Silicon is the most critical component as it interacts with the particles, Madrid explained. When a particle collides with silicon, it leaves behind energy, which is recorded as an electrical signal. That signal is then digitized and recorded as data on a computer.

The silicon is placed within a titanium base plate that secures it. On top of the silicon is a printed circuit board that reads the electrical signals.

Texas Tech is one of several partners working on the project. In all, the detector will require approximately 26,000 modules with each of the partner groups committed to delivering roughly 5,000 modules.

“These modules were built after years of research and development: setting up the lab, getting everything ready and training personnel,” Madrid said. “We made some bad modules and learned from that, but then we made a good batch that worked. These are the first ones that survived all of the stress tests and will be used in the detector.”

For now, Madrid said each module takes about a week to go through the lab’s system of being assembled, connected and secured. Much of this is done by robotic equipment, ensuring each module is put together according to precise specifications.

“We are part of a very large project upgrade that is using dozens of universities across the country and working together in a lot of labs,” Madrid said. “So, there are a lot of moving parts. Internationally, there are a lot of people in a lot of countries working together, so everything will get finished, but it will take time.”

Madrid believes the upgraded detector will lead to new particle physics discoveries.

“We build these massive detectors simply to look at all the particles that come out of these collisions,” he said. “And the hope is that we will see something new, something interesting. That is what we’re hoping for.”

Lee emphasized that this important moment for the department was a team effort, requiring sustained time and focus.

“I am extremely proud of the dedication and expertise of our faculty, postdocs, technical staff and students who made this possible,” he said. “This accomplishment highlights Texas Tech’s important role in advancing particle physics research on the international stage, further elevates our university’s reputation as a leading research institution and reaffirms our commitment to fundamental scientific discovery through the CMS experiment at CERN.”