1 / 16

REX-ISOLDE F. Wenander ATC meeting 23/1-2007

Emiliano Piselli (EP) new since 1/9 2006 50% REX operator. Didier Voulot (DV) (REX phys, contact). Fredrik Wenander (FW) (REX phys, contact). Richard Scrivens (RS). T eam REX. REX-ISOLDE F. Wenander ATC meeting 23/1-2007. REX intro and performance Technical aspects

mills
Télécharger la présentation

REX-ISOLDE F. Wenander ATC meeting 23/1-2007

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Emiliano Piselli (EP) new since 1/9 2006 50% REX operator Didier Voulot (DV) (REX phys, contact) Fredrik Wenander (FW) (REX phys, contact) Richard Scrivens (RS) Team REX REX-ISOLDE F. Wenander ATC meeting 23/1-2007 • REX intro and performance • Technical aspects • Integration and maintenance • Operational issues • Future and Conclusion

  2. Layout * charge breeding * 1+ ions to n+ REXEBIS MASS SEPARATOR Optional stripper ISOLDE 7-GAP RESONATORS @ 101.28 MHz 9-GAP RESONATOR @ 202.56 MHz ISOLDE beam Primarytarget High energydriver beam protons IH RFQ Rebuncher 60 keV 0.3 MeV/u 3.0 MeV/u 2.2 MeV/u 1.2 MeV/u REXTRAP Experiments * longitudinal accumulation and bunching * transverse phase space cooling * 6 cavities * 100 and 200 MHz, ~100 kW * 300 keV/u to 3 MeV/u

  3. REX – a broad spectrum The machine covers pulsed high tension, LN2 and LHe cryogenics, superconducting elements, UHV (1E-11 mbar), a scalable heavy ion linac, ‘invisible’ radioactive beams, high current electron beam, multi-charge ion source, quickly pulsed machine (short-lived elements), electrostatic and magnetic transport, exotic beam diagnostics, etc etc One of its kind!

  4. Comparison with Linac3 Heavy ion linac; similar energy; same # cavities linac but REX: • Built as an experiment • Not ‘standarised’ solutions • Heterogeneous subsystems • More compact, less analysing equipment • Varying elements (ion A/q) and beam energies • different for each run • stable beam for calibration + radioactive isotopes • ~20 isotopes/year, short runs - 3 days to 2 weeks • Low intensity beams - <100 particles/s to 1 nA • Beam injected from another machine (ISOLDE) • No injection into another accelerator • lower energy and emittance constraints

  5. * So far 45 radioactive isotopes (19 elements) 13 and 9 new isotopes 2005 and 2006 * 9 out of 10 successful runs during both runs REXTRAP separation of 40K and 40 Ca REX performance * Recent two year’s outstanding results 1. Energies now from 300 keV/u to 3.15 MeV/u 2. Mass range exceed specifications A~200 now possible, spec A<50 3. Breeding efficiency fulfilling design specs 4. Molecular beams 5. Isobaric mass resolution 6. Development work

  6. Operation 2006 + Beam delivered to experiments in time for runs tougher mini-coordination + Low energy part has been ‘ticking like a clock’ - Late pre-startup for first run (mid June) even if target date 1/4 RF not ready due to: vacuum leak in a cavity DV away 2 weeks, FW tied up with low energy part REX low priority - Sudden electron cathode failure prevented one test run - Problems with RF amplifiers - Discrepancy ISOLDE target yield to exp beam intensity Non-working FCs; Running in problems with new control system; Mechanical problems with tuners; Water leaks at EBIS; Amplitude pickup for IH failed; Forced patch installation on computers during runs; Capacitor in 9-gap amplifier broken (due to long power cut); Beam diagnostic FEC unstable etc…

  7. Remaining serious technical problems * Fragile electron cathode in EBIS No real alternative available (IrCe also breaks) Operate restrictively (i.e. low current ~200 mA) * Power and duty cycle limitation of 200 MHz amplifier Manufacturer required to modify the unit * Scaling of Linac not always fully reproducible Continued and deepened study this year (linearity phase, amplitude, optics) * Problematic to inject into the experimental setup Complete realignment with Minimove Extra quadrupole doublet lens Add an ISOLDE-type beam scanner grid after bending magnet * Late startups – REX lowest on the food chain Avoid Witch (9 T unshielded magnet) runs before a REX run Stricter time limits to support groups

  8. Integration / Consolidation Started 1 Jan 2004 – run for 6 years What remains? • Alignment started end of 2006 • BDI migration to Linux in progress; application programmes missing no hardware consolidation done; under discussion what to change • CO transfer of REXEBIS control to Linux in progress remains to move REXTRAP and beam transfer line optics to Linux 50% of the job done • PO REXEBIS consolidation in progress (to be finished spring 2007) REXTRAP remains 66% of the job done • RF miscellaneous hardware work to do 50% of the job done • VAC overhaul of the PLC programming; control system and application programmes missing minor hardware changes to carry out 30% of the job done REX operation and consolidation within budget every year

  9. REX daily technical support Under responsibility of AB groups since 1 Jan 2004 (before PH) * Application programmes Inefficient(?) to re-specify existing application programmes 50% of EP is allocated for ISOLDE application programming * Group support BDI – hardware interventions started up since 1 year, knowledge transfer in progress CO – part transferred to Linux covered PO – fully autonomous since >2 years, planning, implementation, documentation, callout RF – self-governed together with DV, planning, REX low priority, callout VAC- limited service; mounting of vacuum parts mostly not covered Situation improved significantly since 2004; still much job covered by REX phys (DV+FW) * General technical support Daily repair / maintenance and shutdown work done be DV and FW Technicians from AB/RF, ATB/IF, ABP/HSL help out occasionally

  10. Piquet * <5 support group call-outs outside working hours 2006 (all for RF or TS) * 30-40 REX phys (DV+FW) call-outs outside working hours excluding late setups and changes most problems solved by REX operators mini-course for the users before each run * Increased need for piquet interventions when REX -> AB systems * Recall – REX has short runs

  11. Day 0 RS assists low energy EP under training whole machine Day 1 Day 2 Day 3 Beam setup tasks and time I ISOLDE setup - Separator setup + proton scan on target (4-8 h) (ISO operators) - Basic target test (2-3 h) (ISO target sec+FW) - Understand beam behaviour (0-2 h) (FW) REX setup - Stable beam from EBIS through linac (2-4 h) (DV) - Beam from ISOLDE separator (2-4 h) (FW) - Beam through trap (3-4 h) (FW) - Beam injection into EBIS and REX separator (4-6 h) (FW) Late work - Continued linac tuning with stable beam (2-4 h) (DV) Early start - Determination of A/q, breeding times etc (2 h) (FW) - Radioactive beam to users (3-6 h) (DV+FW) depending on beam intensity and exp setup - General checks and further optimization of beam steering to experimental setup (DV+FW)

  12. Beam setup tasks and time II In addition squeeze in (Day 0 to 2) Advanced yield tests if required and requested (2-6 h) (ISO target sec) RILIS laser tuning with ISOLDE (if applicable) (2-4 h) (Laser experts) During actual run Each change of isotope or energy (2-8 h) (DV+FW) Yield checks (ISO target sec+FW) Optimisation and verifications (DV+FW) General comments * REX startup time >24 h effective time * Quality assurance (beam efficiencies) * Overview and effectiveness necessary coordinate ISOLDE, target tests, lasers, REX low energy, REX high energy, exp beam calibration run the setup in parallel were possible make use of the machine; early morning to late night, lunch in shifts RS assists EP under training

  13. Operational issues + REX is easier to operate nowadaysunderstanding increased dramatically running well considering its complexity • - Changes during evenings and weekends (goodwill basis) • situation unclear / difficult to refuse requests / maximise physics output • - REX physicist (DV+FW+RS) used for standard / repeated operation • - Overtime issues • on call 10 weekends REX + 2 weekends Linac3 (FW) • on call 10 weekends REX (DV) => operator status • ! OP involvement just started 1/9-2006 (EP) • very good news • ! Aim to transfer daily REX operation to OP • liberate ‘senior’ physicist staff for suited tasks • ! Recommend involvement of a 2nd ISOLDE operator • >1 year training period; cover the whole chain

  14. So why is REX working? * In-house knowledge and overview a small complex ‘one-of-a-kind’ machine must / can be known by heart * Local actions short runs requires rapid interventions -> repair things ourselves * Beam responsible and not only machine responsible knowledge of whole chain (protons -> ISOLDE -> REX accelerator-> experiment) * Mini-schedule and tight coordination effective use of time and ISOLDE * Considerable operator presence in the hall during the runs * Built by PhD students and fellows (one still around) dedication, pride and a REX spirit in the team

  15. EBIS test stand Minimove and Visions Minimove * Improved exp setup * Better beam optics * DV digging in -> progressing well! Energy upgrades * Increase physics potential * Assure facility stays competitive BNL type EBIS * Handle heavy elements well * Higher capacity

  16. Summary Problems * REX a low priority machine – people have scattered responsibilities * Responsibilities not yet not fully transferred to the support groups * REX physicists (DV+FW) cover other’s work * Missing dedicated part technician (as Linac 2/3 superintendent) * Daily / standard operation not transferred to OP Ideas and solutions * Don’t split the machine into low energy and high energy part? * Coordination physicist (target - ISOLDE separator – REX) * Improved situation after LHC completion (but 3 MeV test stand and Linac4 coming up…) * High in-house competence for the REX operators * Involve another ISOLDE operator in the REX Physics community until now very happy with REX

More Related