High Luminosity Large Hadron Collider

The High Luminosity Large Hadron Collider (HL-LHC; formerly SLHC, Super Large Hadron Collider) is an upgrade to the Large Hadron Collider started in June 2018 that will boost the accelerator's potential for new discoveries in physics, starting in 2027.[1] The upgrade aims at increasing the luminosity of the machine by a factor of 10, up to 10³⁵ cm⁻²s⁻¹, providing a better chance to see rare processes and improving statistically marginal measurements.

Hadron colliders

Intersecting Storage Rings	CERN, 1971–1984
Proton-Antiproton Collider (SPS)	CERN, 1981–1991
ISABELLE	BNL, cancelled in 1983
Tevatron	Fermilab, 1987–2011
Superconducting Super Collider	Cancelled in 1993
Relativistic Heavy Ion Collider	BNL, 2000–present
Large Hadron Collider	CERN, 2009–present
Future Circular Collider	Proposed

History

Many different paths exist for upgrading the collider. A collection of different designs of the high luminosity interaction regions is being maintained by the European Organization for Nuclear Research (CERN).[2] A workshop was held in 2006 to establish which are the most promising options.[3]

Increasing LHC luminosity involves reduction of beam size at the collision point and either reduction of bunch length and spacing, or significant increase in bunch length and population. The maximum integrated luminosity increase of the existing options is about a factor of 4 higher than the LHC ultimate performance, unfortunately far below the LHC upgrade project's initial ambition of a factor of 10. However, at the latest LUMI'06 workshop,[3] several suggestions were proposed that would boost the LHC peak luminosity by a factor of 10 beyond nominal towards 10³⁵ cm⁻²s⁻¹.

The resultant higher event rate poses important challenges for the particle detectors located in the collision areas.[4]

As of 2011, the project was led by Lucio Rossi.[5][6]

Injector upgrade

As part of the Phase 2 Super LHC, significant changes will be made to the proton injector.

Superconducting Proton Linac (SPL): Accelerating protons with superconducting radio frequency cavities to an energy of 5 GeV.

Proton Synchrotron 2 (PS2): Accelerating the beam from 5 GeV at injection to 50 GeV at extraction.

Super Proton Synchrotron (SPS) Upgraded: The present SPS will be substantially upgraded to handle an increased beam intensity from PS2.

References

1. "A new schedule for the LHC and its successor". 13 December 2019.
2. IR optics collection
3. LUMI 06 workshop
4. ATLAS upgrade web page
5. "Faces and places: Lucio Rossi is named 2013 IEEE fellow". CERN Courier. 53 (1): 37. January 2013.
6. Rossi, Lucio (7 September 2018). "Lessons from the accelerator frontier". CERN Courier. 58 (7). p. 5-6. Retrieved 24 February 2020.

External links

• The HL-LHC Project: High Luminosity Large Hadron Collider project web page
• A comprehensive press article on the 2006 workshop can be found at the CERN Courier.
• A summary of the possible machine parameters can be found at Machine parameters collection.