LIU-Ions overall status and outlook: LEIR H. Bartosik for the LIU-IONS LEIR team* with lots of material from “Beam dynamics studies on LEIR”, H. Bartosik, A. Huschauer, V. Kain and input from R. Scrivens January 18, 2015

Present understanding of losses at capture Iso-adiabatic capture in single/double RF with and without gun modulation (longitudinal blow-up) Clear dependence of losses on line charge density Highest intensities achieved with flat bunch profile in double harmonic (hollow distribution)

Present understanding of losses at capture Accumulation Space charge tune spread increases along with injections and cooling

Present understanding of losses at capture Accumulation Space charge tune spread increases along with injections and cooling Capture Space charge tune spread increases (~ factor 2) and particles are pushed onto betatron resonances  emittance blow-up and losses

Resonance compensation norm: ON skew: ON norm: ON skew: OFF norm: ON skew: ON norm: OFF skew: OFF LEIR has independent harmonic sextupoles (presently 2 skew & 2 normal) usually not used A first attempt was made to compensate sextupolar resonances  polar scan of sextupole currents 10-15% increase of intensity was achieved with optimal settings found so far

Intensity evolution in December NOMINAL exchanged Linac3 stripper foil “oven shaking”harmonic sextupoles no data in Timber record intensity!

Intensity evolution in December NOMINAL exchanged Linac3 stripper foil “oven shaking”harmonic sextupoles no data in Timber record intensity!

Transmission as function of intensity MDNOM Data points clustered depending on daily machine / beam conditions % transmission for up to 7e8 Pb54+ accumulated NOMINAL Some shots with > 80 % transmission for up to 8e8 Pb54+ accumulated Further improvement for high intensity should be possible NOMINALMDNOM

Main achievements of 2015 Pb-ion run Series of detailed machine studies Machine optics (including closed orbit, tune and chromaticity correction), space charge, transverse damper, optimization of capture (including longitudinal emittance blow-up using e- cooler gun modulation), resonance compensation using harmonic sextupoles, RF, e-cooler, injection line matching, impedance, … Detailed measurements for different beam conditions (most of the data still to be analyzed) Space charge identified as main source of losses at RF capture Incoherent direct space charge tune spread pushes particles onto betatron resonances Losses depend on line charge density  mitigation by longitudinal blow-up and double harmonic Improved transmission using harmonic sextupoles (currents empirically optimized) Optimizations performed on MD cycle migrated to operational cycle Intensity out of LEIR was steadily improved over the 8 weeks of the 2015 run Achieved new record intensity of about 7e8 Pb54+ out of LEIR at the end of the run

Beam dynamics studies to be done in 2016 (1) Resonance compensation to mitigate losses at capture Measurement of Resonance Driving Terms using turn-by-turn data from transverse feedback PUs (cables to be pulled during YETS 2015/16) Optimal usage of existing correctors (harmonic sextupoles, sextupole correctors in main bends) Optimization of RF capture process to mitigate losses at capture Maximize longitudinal emittance and bunching factor (blow-up using gun modulation, second harmonic to generate flat bunch profile, hollow distribution, …) Improve reproducibility (impact of beam intensity on beam momentum after cooling, …) New optics with optimized working point to avoid 3 rd order resonances Optics studies in MADX including definition of tune and chroma knobs Implementation of new optics in LSA (optics definition, tune and chromaticity control, …) E-cooler 400 mA operation and maximum cooling rate in view of 10 Hz injection rate Optimal settings for maximizing transmission (smallest emittance not ideal due to space charge?) Explore limitations for accumulated intensity with 10 Hz injection rate Injection efficiencies for high number of injections

Beam dynamics studies to be done in 2016 (2) Re-matching injection transfer line During early phase of beam commissioning Magnetic model of LEIR in view of space charge studies Fit systematic multipole components based on measured non-linear chromaticity Magnetic model of main bending magnets Field map of e-cooler Space charge Development of simulation model to reproduce machine observations Optimization of working point based on simulation model Explore possibilities of RF gymnastics in LEIR Possibilities for longitudinal blow-up using RF system (needs new low level RF) Use both RF cavities (needs new low level RF) Bunch splitting Impedance (to exclude intensity limitations due to instabilities) Beam based measurements (detuning with intensity, growth rates, …) Analytical and numerical models

Other activities in 2016 and beyond (1) YETS 2015/2016 Opening of vacuum sector 5 to investigate losses in extraction region during injection process Replacement of MCP in IPMs Pull cable for turn-by-turn readout of transverse damper pick-ups to access signals before BOSS unit Repair and replacement of SEM grids in transfer line Repair of burnt BTV screens New digital low level RF (2016) With possibility to use both cavities Compensate for dependence of RF capture frequency on intensity? Renovation of LSA cycle generation (2016 and beyond) Clean-up of make rules Include transfer lines in corresponding particle transfer Proper definition of default values

Other activities in 2016 and beyond (2) Beam instrumentation upgrades Discussions on beam instrumentation requests presently ongoing (e.g. SEM grids and BPMs in transfer lines, new electronics for turn-by-turn readout of LEIR ring BPMs, new Schottky system, …) Integration of transfer line into YASP (until startup 2016) Ideally using non-destructive measurement systems Facilitates steering and optics measurement/matching Requires model of the line in LSA and creation of makerules Upgrade of transverse feedback system (YETS 2015/16) Improved feedback phase control along the cycle Programmable gain along the cycle PS stray field compensation (2016) Algorithm has been implemented by CO and is ready for testing LEIR external beam dump (see next slide)

LEIR external beam dump Provide a safe beam dump for accelerated ions not request by the PS. Thermal and radiation modelling ongoing. Layout and integration needs finalisation. Aim to install in YETS 2017/18. Activity coordinator(s) will pick this up very soon with all the stake holders. Magnet ETL.BHN10 LEIRD “Y” Chamber Scheme, but layout needs modification.

Operating LEIR and integrating SPS operators Long term goal to better integrate LEIR into the operation of SPS: Use more LSA and YASP to speed up operational setting up and tuning. Develop applications for some tasks, (by SPS operators, with look and feel of SPS, e.g. equip state). Training for operators. Get the operators involved in −Cold check out −Beam setting up through scanning (specifically for optimisation). Planning of the 2016 restart to start soon: ~3 weeks (total) of Hardware Commissioning and cold check out in April. Get the details of what new equipment will need commissioning (e.g. LLRF). Start implementing start up check lists. Identification of who is involved asap, and very regular co-ordination

Thank you for your attention!