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Barrel Timing Layer (BTL) Tracker Support Tube for Large Hadron Collider

The large carbon fiber sandwich structure was designed by a joint team from Purdue University

Completed hardware with the tooling used for manufacture

This month Rock West Composites delivered a large, high-precision, carbon fiber and honeycomb core tube to Purdue University. The structure is the Barrel Timing Layer Tracker Support Tube that is part of an upgrade to CERN’s Compact Muon Solenoid (CMS), which is a general-purpose detector at the Large Hadron Collider.

Rock West Composites (RWC), US, recently announced the delivery of the Barrel Timing Layer (BTL) Tracker Support Tube to Purdue University. This large carbon fiber sandwich structure destined for CERN was designed by a joint team from Purdue University, led by Dr. Andy Jung and Dr. Ben Denos, and RWC, led by John Marks. The collaborative effort met key performance parameters using the most cost-effective design. The hardware RWC delivered will be integrated with instrumentation from Purdue prior to delivery to CERN.

RWC is an employee-owned, advanced composites company that develops, engineers, manufactures, and tests composite products for multiple industries

CERN is the world’s leading laboratory for particle physics located near Geneva, Switzerland. The carbon fiber tube supports the heart of the upgraded CMS detector, a “camera” with more than a billion pixels to record proton-proton collisions at the highest ever-made energies and unprecedented resolution. In a few years, once fully commissioned, the upgraded CMS detector is expected to collect 10 times the data recorded so far in the hunt for new particles and aims to understand the origins of the Universe.

The BTL Tracker Support Tube had to be manufactured from materials with extremely low radiation resistance, have a precise circular cylinder structure, be very strong and stiff, and meet an accelerated delivery schedule. Because the final tube had such challenging requirements, traditional tooling or manufacturing approaches would have been unaffordable. Innovative techniques were used, starting with the manufacture of curved, solid laminate arc segments rather than a full cylinder. Precision machined arc segment stiffeners help hold the arcs to strict dimensions once assembled. Low coefficients of thermal expansion are maintained in all 3 directions: radially, circumferentially, and along the length of the tube.

Prior to making the full-scale tube, RWC built a full diameter but much shorter version of the part as a technology demonstrator. RWC was presented with an Industry Gold Award from CERN in 2022 for this effort, and ultimately won the program from Purdue for the full-size hardware due to the success of the demonstration model and its affordability.

The delivered hardware is 5.3-meters long by 2.4-meters in diameter. It is constructed of ultra-high-modulus prepreg and Nomex honeycomb core made with PMT-F6 cyanate ester resin. There are 1680 metallic inserts made of solid carbon epoxy, titanium and stainless steel; and it includes two 110 MSI carbon fiber (K13916/ F6) rails to support scientific instruments. Surface accuracy requirements were tested to 2.4mm cylindricity inhouse before shipment.