On 2 September, O. Brüning, HL-LHC Project Leader, was invited by S. Redaelli, WP5 leader, to visit the workshop where the crystal primary collimators (TCPCs) are being assembled. The SY/STI and the BE/CEM management (S. Gilardoni and A. Masi, respectively) and other key people involved in this activity joined the visit.

The purpose of the visit was to inspect the TCPC assemblies before mounting the bent crystals in them, and before closing their vacuum tanks, prior to the installation in the LHC tunnel. The installation of the bent crystals in the TCPCs is planned for mid-October, upon completion of the crystal validation measurements. The TCPC installation in the LHC IR7 is planned for the YETS2021-22.

Two TCPC assemblies have been built at CERN in 2021, following a crash programme launched by WP5 after the decision in late 2020 not to install during LS2 the 11 T dipoles in the dispersion suppressors around IR7. Instead, crystal collimation will be used to improve the collimation performance with heavy-ion beams during Run 3. The two TCPC units will replace two of the four TCPC test devices installed in the LHC between 2015 and 2107, and tested with beam during Run 2. The installation will be completed in the YETS2022-23 when the other two old TCPCs will be replaced by two new TCPCs.

By Stefano Redaelli, WP5 Leader.

Related photos: link.