Vilnius University physicists are refining the assembly of electronic components with wires thinner than a human hair, measuring just 25 micrometres (µm), for an upgrade to the Compact Muon Solenoid (CMS) detector at CERN. On July 1, 2026, CMS inner tracker representatives Marko Dragicevic and Giacomo Sguazzoni approved Vilnius University’s participation in assembling and testing modules, praising both the work and the available equipment. VU physicists are the only team in Lithuania focused on this crucial step for the Tracker Endcap Pixel (TEPX) modules, verifying their durability and performance before integration into the detector. “We are involved in the assembly and testing of semiconductor electronics,” says Dr. Andrius Juodagalvis, Head of the Experimental Nuclear and Particle Physics Center at Vilnius University, explaining that the upgrade is necessary to prepare for the increased luminosity of the Large Hadron Collider.
Researchers at VU’s Experimental Nuclear and Particle Physics Center receive mechanically connected modules, then employ ultrasonic wire-bonding to establish electrical connections between the silicon sensor and the readout chip. Following this initial connection, the modules undergo rigorous testing to verify functionality and durability before receiving a protective coating. Specialized equipment and software are then used to confirm the device accurately reads electrical signals, essential for particle detection within the upgraded CMS detector. This upgrade is a necessary preparation for the High-Luminosity Large Hadron Collider (HL-LHC), where proton collisions will increase dramatically from the current rate of approximately 60 to as many as 200 simultaneous collisions.
Dr. Juodagalvis explains that this increased collision frequency, occurring 40 million times per second, will allow scientists to extract more valuable data and observe previously undetectable rare events, potentially revealing new physics beyond the Standard Model and providing insight into mysteries like dark matter. VU researchers are currently the sole team within Lithuania focused on refining the assembly and testing of the electronic components for the TEPX modules, essential for the detector’s enhanced capabilities. This specialized work involves connecting silicon sensors to readout chips with wires measuring only 25 micrometres (µm) in thickness, a dimension smaller than a human hair, requiring microscopic precision. The team receives mechanically connected modules and utilizes ultrasonic wire-bonding to establish these delicate connections in their laboratory. This approval signifies a crucial milestone in the upgrade process, confirming the university’s capacity to contribute to this international collaboration. The impetus behind this upgrade is to increase the luminosity of the LHC, effectively boosting the rate of proton collisions; currently, around 60 collisions occur, but after the upgrade, that number is projected to reach up to 200 simultaneous proton collisions, each lasting just 25 nanoseconds.
Dr. Juodagalvis states that they’ll be able to extract much more valuable data from this and observe rare processes, emphasizing the potential for discoveries.
For example, the current rate is around 60 collisions. Still, after the upgrade, the proton collisions will be much more intense, reaching up to 200 separate proton collisions at the same time.
