This picture shows the ALICE Miniframe being reinstalled on the detector in mid-November 2020, after a two-year-long stay at the surface for upgrades.

Weighing in at 14 tonnes and measuring 12 metres long, the Miniframe is anything but “mini”: it is a giant “plug” – a large metallic support structure, installed in front of the A-side of the ALICE Time Projection Chamber (TPC) and sitting partially in the L3 magnet. It has supported ALICE’s systems since the detector’s debut, carrying the services for the TPC and ITS (Inner Tracking System), such as power supply, cooling, gas, detector control, detector safety, trigger and data acquisition. It also houses the ALICE forward detectors, FIT-A (Fast Interaction Trigger A), the ALICE RB24 beampipe, and the compensator magnet. The Miniframe was designed to be easily removable in case the TPC needed to be extracted during long shutdown (LS) periods.

This came in handy during LS2, as the TPC was temporarily removed from the cavern for upgrades. In January 2019, the Miniframe was brought to the SX2 surface hall, where it received new services and patch panels for the new ALICE tracker, the ITS2, including kilometres of new cables for the ITS2 and TPC. The support structures and cable trays were re-engineered to accommodate the cables, including the 7000 optical fibres needed to allow continuous readout from the TPC and ITS2.

The upgrades were completed just in time for the reinstallation in November 2020, when the fully refurbished Miniframe was lowered back into the cavern and inserted in front of the detector. Since then, work has been continuing to connect the services, with a view to getting the TPC operating by the end of the year.