ELENA Overview and Layout Start of ELENA Commissioning Next Steps Start of Beam Commissioning of the Extra Low ENergy Antiproton ring (ELENA) C. Carli on behalf of the AD/ELENA team(s) ABP Information Meeting 20th April 2017 ELENA Overview and Layout Start of ELENA Commissioning Next Steps Start of ELENA Beam Comissioning ABP Meeting, 20th April 2017

ELENA Overview and Layout High sensitivity magnetic Pick-up (Schottky diagnostics for intensity, LLRF..) Extraction towards new experimental zone (fast deflector) followed by el.-static transfer lines Injection with magnetic septum and kicker Compensation solenoids for (not yet Installed) cooler Wideband RF cavities (very similar to new PSB cavities) Line From AD Extraction towards existing experiments Scraper to measure emittance Deceleration of antiprotons from 5.3 MeV to 100 keV to improve efficiency of experiments Circumference 30.4 m (1/6 the size of the AD), magnetic ring and electrostatic extraction lines Challenges related to low energy as field quality of magnets operated with very low fields Start of ELENA Beam Comissioning ABP Meeting, 20th April 2017

Start of ELENA Commissioning – Ion Source Aim: progress as much as possible without taking “expensive” antiprotons Source available and tested well in advance 100 keV (post-acceleration), source a few meters from Faraday cage with HV cables in between First tests with source mounted in Faraday cage Technical issues despite serious preparations Isolation transformer(s) broke several times =>Now running with fixed transformer at 85 keV No beam since last week due to vacuum issues Faraday cage Source Thanks a lot to the team from Jülich providing source as in-kind contribution for all the efforts and flexibility Start of ELENA Beam Comissioning ABP Meeting, 20th April 2017

Start of ELENA Commissioning – Transfer line Electro-static line from source to ring Missing monitors (in-kind) make understanding difficult Empirical adjustments allowed bringing the beam to ring within few days, but led to unexpected settings Excellent to see beam on TV station close to ring Recent efforts to be invested to understand did not (yet?) improve Source Profile monitor prototype issues to interpret signals available since ~a month Signals from horizontal wires TV station almost only instrumentation available One of the first acquisitions from November 2016 Start of ELENA Beam Comissioning ABP Meeting, 20th April 2017

Start of ELENA Commissioning – Ring Beam observed over several 10s of turns (probably a few ms) in November ‘16 after less than 2 weeks Beam lost quickly or just not visible any more due to debunching? Commissioning of RF system as next under preparation, when source broke (insulation transformer) With 85 keV H- after commissioning of RF system Beam shown to survive at least until start of ramp Only very basic RF functionalities, no phase loop Tunes from injection oscillations using OASIS Synchrotron oscillation, debunching …. Seen with OASIS Position pick-up sum signals 50 ms/div 50 ms/div So far not conclusive – change of quad settings did not shift tunes as expected 1 ms/div About 150 ms after injection ~1.5 106 H- ??? Start of ELENA Beam Comissioning ABP Meeting, 20th April 2017

ELENA Commissioning – Next Steps Get ion source up and running again Briefly switch to protons for a test of the profile monitor, then probably 85 keV H- to resume ring commissioning (stay at 85 keV even with new isolation transformer?) Consolidate injection line and injection into ring First: back to injection line setting from 5th and 6th April, when injection was good Further studies to understand and empirically improve line and injection Commissioning of instrumentation and understanding machine at low energy Orbit system – orbit correction and orbit response studies “Tomoscope” – observe bunching (& independent intensity estimate) Tune measurement and correction (first test of pick-up indicated good performance Acceleration (deceleration), injection of antiprotons … setting up of antiproton cycle Requires electron cooler finally to be available and installed Requires profile monitors! First 100 keV beam (probably H- and/or protons) for GBAR Requires profile monitors!! First data from orbit system – looks “credible”, to be understood/consolidated … Start of ELENA Beam Comissioning ABP Meeting, 20th April 2017

Thanks for your attention ! Start of ELENA Beam Comissioning ABP Meeting, 20th April 2017

Start of ELENA Beam Comissioning ABP Meeting, 20th April 2017 Introduction: Antiproton Decelerator AD – a unique facility providing 5.3 MeV antiprotons (3 107 in <300 ns) ~1.5 1013 protons (26 GeV) on target ~3.5 107 antiprotons captured in AD Acceptances 200 mm and ±30 10-3 Deceleration to the lowest energy 5.3 MeV reachable “safely” (limited by mag. Fields?) Stochastic and electron cooling at four different energies ~3 107 antiprotons extracted per cycle Dense core containing ~70% within <1 mm, often tails up to 10 mm Longitudinal before bunch rotation 95% within 10-4 and 400 ns Cycle length about 100 s Location for future ELENA installation Sketch of the present AD – circumference 182 m - In addition experiment AEGIS installed - Experiment BASE being installed - Gbar approved to receive beam from ELENA Start of ELENA Beam Comissioning ABP Meeting, 20th April 2017

Introduction: Efficiency for capturing antiprotons in traps without and with ELENA 5.3 MeV antiprotons a shot every ~ 100 sec to one experiment ~4 keV antiprotons/ ~ 100 sec ~ 3 x 107 Present situation with AD alone: - Most experiments slow antiprotons down by “degrader” => very inefficient – most (>99%) antiprotons lost (one experiment uses an RFQ for deceleration with higher efficiency) 100 keV antiprotons a shot every ~100 sec shared by ~4 experiments ELENA ~ .45 x 107 Future situation with AD and ELENA decelerating to 100 keV: - thinner “degrader” and increased trapping efficiency (some experiments use other means to decelerate the beam) - Intensity shared by four exp’s allows longer periods with beam Start of ELENA Beam Comissioning ABP Meeting, 20th April 2017

ELENA Overview and Layout Extraction towards existing experiments (with fast electrostatic deflector) Line from H- and proton source for commissioning Wideband RF cavity Injection with magnetic septum (≈300 mrad) and kicker (84 mrad) Scraper to measure emittances (destructive) Quadrupoles High sensitivity magnetic pick-up for Schottky diagnostic (intensity) and LLRF Electron Cooler and compensation solenoids Extraction towards new exp. zone Deceleration of antiprotons from 5.3 MeV to 100 keV to improve efficiency of experiments Circumference 30.4 m (1/6 the size of the AD) Fits in available space in AD hall and allows installing all equipment without particular efforts Lowest average field (beam rigidity over average radius) Br/R = 94 G (smaller than for AD 115 G) Start of ELENA Beam Comissioning ABP Meeting, 20th April 2017

ELENA Installations (Photos from about two weeks ago) Ring with all dipoles and quadrupoles installed Transfer Lines part required for ring commissioning Start of ELENA Beam Comissioning ABP Meeting, 20th April 2017