LEIR Commissioning

The Low Energy Ion Ring (LEIR) is a central piece of the injector chain for LHC ion operation, transforming long Linac 3 pulses into high density bunches needed for LHC. LEIR commissioning is scheduled to be completed at the time of the conference. A review of LEIR commissioning highlighting expected and unexpected problems and actions to tackle them will be given

Beam Loss in the Low Energy Ion Ring (LEIR) in the Light of the LHC Injector Upgrade for Ions (LIU-Ions)

For the LHC injector upgrade, the Low Energy Ion Ring (LEIR) is requested to deliver twice the intensity per extraction compared to the last Pb⁵⁴⁺ ion run in 2013 (i.e. 2 bunches of 5.5·10¹⁰ charges). As the number of injected ions has been increased into LEIR, a fast loss is observed during the RF-capture of the electron cooled ion beam, and this loss today leads to an effective saturation of the available ion intensity at extraction. We have observed transverse oscillations for both Pb⁵⁴⁺ and Ar¹¹⁺ ion species at the beginning of the beam loss via the high bandwidth pickups from the tune measurement system. For these transverse oscillations a growth time comparison will be presented in order to categorize the nature of the observed ion beam loss. The chromaticity has also been measured for both ions. For Pb⁵⁴⁺ this has been measured during the magnetic ramp by creating a radial offset with the LEIR RF system, whereas for Ar¹¹⁺ it was measured on the flat bottom with a coasting beam and controlling the beam momentum with the electron cooler, i.e. without RF. In addition, Schottky spectra will show the symptoms of the beam loss seen in the longitudinal plane

The ELENA facility

The CERN Antiproton Decelerator (AD) provides antiproton beams with a kinetic energy of 5.3 MeV to an active user community. The experiments would profit from a lower beam energy, but this extraction energy is the lowest one possible under good conditions with the given circumference of the AD. The Extra Low Energy Antiproton ring (ELENA) is a small synchrotron with a circumference a factor of 6 smaller than the AD to further decelerate antiprotons from the AD from 5.3 MeV to 100 keV. Controlled deceleration in a synchrotron equipped with an electron cooler to reduce emittances in all three planes will allow the existing AD experiments to increase substantially their antiproton capture efficiencies and render new experiments possible. ELENA ring commissioning is taking place at present and first beams to a new experiment installed in a new experimental area are foreseen in 2017. The transfer lines from ELENA to existing experiments in the old experimental area will be installed during CERN Long Shutdown 2 (LS2) in 2019 and 2020. The status of the project and ring commissioning will be reported

CERN ELENA project progress report

The Extra Low Energy Antiproton ring (ELENA) is a CERN project aiming at constructing a 30 m circumference synchrotron to further decelerate antiprotons from the Antiproton Decelerator (AD) from 5.3 MeV to 100 keV. The additional deceleration complemented by an electron cooler to reduce emittances will allow the existing AD experiments to increase substantially their antiproton capture efficiencies and render new experiments possible. The ELENA design is now well advanced and the project has entered the construction stage, in particular for what concerns the infrastructure. Installation of the machine components is foreseen during the second half of 2015 and beginning of 2016 followed by ring commissioning until the end of 2016. New electrostatic transfer lines to the experiments will be installed and commissioned during the first half of 2017 followed by the first physics operation with AD/ELENA end of 2017. Main ELENA related infrastructure progresses as well as the status of the project are reported

ELENA: Installations and Preparations for Commissioning

The Extra Low Energy Antiproton ring (ELENA) is a small 30 m circumference synchroton under construction at CERN to further decelerate antiprotons from the Antiproton Decelerator AD from 5.3 MeV to 100 keV. Controlled deceleration in a synchrotron equipped with an electron cooler to reduce emittances in all three planes will allow the existing AD experiments to increase substantially their antiproton capture efficiencies and render new experiments possible. Installation of the machine and lines needed for the commissioning of the ring are ongoing and commissioning is expected to start around mid-2016. The aim is to complete ELENA ring commissioning in November followed by the installation of new electrostatic transfer lines to existing experiments until autumn 2017. Status of ELENA installations and preparations for commissioning will be reported

ELENA: the extra low energy anti-proton facility at CERN

At the last LEAP conference in Vancouver 2011 the authors stated that a project ”ELENA”, as an abbreviation for Extra Low ENergy Antiproton ring and as first discussed in 1982 for LEAR by H. Herr et al., was freshly proposed with a substantial new design and revised layout and that it was under consideration to be built at CERN. ELENA is an upgrade of the Anti-proton Decelerator (AD) at CERN and is devoted to special experiments with physics using low energy anti-protons. The main topics are the anti-hydrogen production and consecutive studies of the features of this anti-matter atom as well as the anti-proton nucleon interaction by testing the QED to high precision. During the last years the project underwent several steps in presentations at different committees at CERN and was finally approved such that the construction has started. ELENA will increase the number of useful anti-protons by about two orders of magnitude and will allow to serve up to four experiments simultaneously. Very first and convincing results from the experiments at the AD have been published recently. For high precision physics, however, it appears to be cumbersome, time consuming and ineffective when collecting the needed large numbers and high densities of anti-proton clouds with the present AD. Both the effectiveness and the availability for additional experiments at this unique facility will drastically increase, when the anti-proton beam of presently 5 MeV kinetic energy is reduced by the additional decelerator ELENA to 100 keV

ELENA - From Commissioning to Operation

In 2021 the Extra Low ENergy Antiproton ring (ELENA) moved from commissioning into the physics production phase providing 100 keV antiprotons to the newly connected experiments paving the way to an improved trapping efficiency by one to two orders of magnitude compared to the AD era. After recalling the major work undertaken during the CERN Long Shutdown 2 (2019-2020) in the antiproton deceleration complex, details will be given on the ELENA ring and the new electrostatic transfer line beam commissioning using an ion source. Sub-sequentially, the progress from commissioning with ions to operation with antiprotons will be described with emphasis on the achieved beam performance. Finally, the impact on the performance of the main hardware systems will be reviewed