Commissioning of proANUBIS: A proof-of-concept detector for the ANUBIS experiment

Abstract

Long-lived particles (LLPs), predicted by various extensions of the Standard Model (SM), have become a key focus of the contemporary search programme for physics beyond the SM. To enhance LLP discovery potential at the LHC, the ANUBIS experiment has been proposed to instrument the ceiling of the ATLAS experiment's underground cavern with dedicated tracking detectors. This report summarises recent progress towards realising ANUBIS. Specifically, a key milestone has been achieved with the installation and commissioning of proANUBIS, a prototype that serves as a proof-of-concept for ANUBIS. We describe the proANUBIS setup, including its remotely-operated data acquisition system and automatic signal processing chain. The proANUBIS demonstrator is used to evaluate the detector performance under realistic conditions in the UX1 ATLAS experimental cavern, including readout synchronisation with the ATLAS experiment. Furthermore, proANUBIS allows for the direct measurement of relevant background processes in a representative location within the ATLAS cavern, providing input for the simulation of such processes for the future ANUBIS detector. The paper concludes with an update on the current status of the ANUBIS project and its roadmap toward a full-scale implementation in the ATLAS cavern.

Figures (12)

• Figure 1: Sketch of the layout of the underground cavern at IP1 of the LHC, featuring the ATLAS experiment, and the PX14 and PX16 access shafts. The area highlighted in orange illustrates the potential ceiling configuration of the ANUBIS detector. In addition to the instrumented cavern ceiling, this configuration includes two discs covering the access shafts.
• Figure 2: (a) Sketch showing the design of proANUBIS metallic frame (in yellow) and its support structure. (b) The location and orientation of the proANUBIS setup within the UX1 ATLAS cavern.
• Figure 3: (a) The yellow proANUBIS steel frame being populated with RPC integrated chambers at CERN's BB5 laboratory. (b) proANUBIS after integration of on-detector services being lifted at BB5 for transport to IP1.
• Figure 4: (a) proANUBIS being lowered with the aid of a crane through the ATLAS PX14 access shaft. (b) The final installation of proANUBIS, along with the primary DCS and DAQ rack, on Level 12 Side A in the UX1 ATLAS cavern. The detector panels of proANUBIS are approximately perpendicular to the line-of-sight towards the IP, which is roughly towards the bottom left corner of the picture.
• Figure 5: Schematic layout of the proANUBIS experimental setup. The system comprises two interconnected parts: the underground UX1 ATLAS experimental cavern hosting the proANUBIS detector and the primary DCS and DAQ rack, and the USA15 area hosting the secondary DAQ rack. The primary DCS and DAQ rack houses the CAEN SY4527 mainframe hosting LV and HV power supplies, the VME crates with a VME controller, TDCs, hardware trigger logic boards, and the timing, trigger, and control interface module for receiving the ATLAS central trigger processor clock. The secondary DAQ rack houses two servers providing backup and full operational redundancy in case of a primary server failure in the cavern. The experimental cavern and USA15 are linked via network switches operating on a dedicated private network to ensure continuous communication and remote control capability.