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Operational aspects 2008 run

ISCOOL. Operational aspects 2008 run. Isolde workshop 17-19 Nov 2008 Erwin Siesling. Hardware Functionality, principle and specs Technical issues 2007/2008 Results 2008 run Shutdown consolidation Summary. Overview. ISCOOL: RFQ cooler and buncher at Isolde. 60 kV. RFQ tank.

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Operational aspects 2008 run

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  1. ISCOOL Operational aspects 2008 run Isolde workshop 17-19 Nov 2008 Erwin Siesling

  2. Hardware Functionality, principle and specs Technical issues 2007/2008 Results 2008 run Shutdown consolidation Summary Overview ISCOOL: RFQ cooler and buncher at Isolde

  3. 60 kV RFQ tank Inj. Triplet Instrum. Ej. Triplet ISCOOL hardware

  4. ISCOOL hardware

  5. ISCOOL hardware RFQ Cooler and buncher Located right after the HRS separator magnets HRS GPS Isolde facility

  6. ISCOOL hardware 60keV HV platform & RF Isolde facility

  7. RFQ: Confines the beam and reduces energy spread for better transmission and higher mass spectroscopy efficiency Bunch mode: Bunches the beam for background supression ISCOOL functionality Continuous mode & Bunch mode

  8. RF RF power:4 transverse rods. Confines the beam Mathieu equation ISCOOL principle RFQ Bunch mode Courtesy Dr. H. Franberg He buffer-gas:Interactions decelerate the particles to a few eV Electrodes:Potentials along the axis. 3 last and extraction plate can be pulsed HV extraction voltage:60kV to extract and accelerate the beam out of the RFQ

  9. Emittance: Transmission: Cooling time: Space charge: Pulse width: ISCOOL specs from 35π.mm.mrad to 2.2 π.mm.mrad better than 70% for A>39 TOF <1ms, one passage enough to cool the beam up to 1E8/s ! depends on space charge and cooling time

  10. The ISCOOL has been performing remarkably well during the 2008 run with only a few minor technical problems 2007/8 shutdown consolidation:- elements controllable from RFQ workingset & QP array - vacuum leaks fixed & interconnections improved- re-aligned 2008 operation issues:- Excessive use of He buffer gas- RF amplifier break down (due to abrupt HV switching) ISCOOL tech issues

  11. Workingset for all elements 2007/8 consolidation • QP arrays: Archive to save and reproduce settings for different targets and users

  12. 2007/8 consolidation Vacuum leaks repaired & connections improved

  13. With beam.. 2007/8 consolidation Re-alignment: ? Aligned with respect to the faraday-cups: displacement of the beam with regard to the scanners of hor -10mm, vert +30mm stayed

  14. 2008 Operation issues He buffergas He Buffergas pressure: ~1E-2 mbar 4He Estimated: 10-2mbar l/s But… • Helium ‘addiction’: • Using 3x more • Bottle needs changing ~6 weeks • Filling-up Isolde gas-recuperation tanks faster

  15. 60kV 2008 Operation issues RF amplifier & synthesizer • High Voltage sensitive: • Break down due to abrupt HV switching • Will be replaced this shutdown (+ spare)

  16. ISCOOL transmission Beamline transmission Bunch mode ISCOOL 2008 results

  17. RFQ tank Inj. Triplet Instrum. Ej. Triplet ISCOOL online transmission Modes Sources ISCOOL transmission >70% for A>39:- In general between 70-80% for plasma targets, somewhat higher for surface ion sources. Depends on the emittance coming from the ion source - In pulsed mode some higher losses related to the trapping time Courtesy Dr. H. Franberg

  18. Merging switchyardlosses 50-70% ~2π.mm.mrad ISCOOL ~35π.mm.mrad Beamline transmission:- low emittance beam after the cooler is easily tuned to the different experiments with a transmission efficiency of up to 100% Beamline transmission Higher mass spectroscopy efficiency 100% transmission GPS HRS

  19. Ernesto Mane: ‘First results using the ISCOOL-COLLAPS apparatus’ Bunch mode Collaps 46K beam 1E5 ions/s after the cooler.Collection time 20 min, with 300ms bunching, 12us gate and 2mW laser power Background suppression of factor ~1E4 by gating on the beam pulse ISCOOLin bunch mode HRS

  20. (10 units = 20us) 20uS Anna Gustafsson: ‘The REX low-energy toolbox’ Bunch mode New 'tricks' for REX injection: REXtrap - Mass purification at REXtrap using RF excitation. - Direct pulsed injection into EBIS without use of the trap: The space-charge of the RFQ bunches is much higher than what can be achieved with the trap. Acceptance of EBIS would be large enough and it would increase beam intensity to the linac. ISCOOL gated by trap timing ISCOOLin bunch mode HRS

  21. 2008/9 shutdown consolidation:- vacuum controls (Julien de Freitas)- new RF amplifier (Pascal Fernier)- MCP re-installed? 2008/9 shutdown

  22. Reliable 2008 performance with very few issues- RF amplifier will be replaced + spare- Vacuum will be integrated in the Isolde controls ISCOOL transmission 70-80% depending on mass and ion source Easy tuning and beamline transmission improved to 100% Bunch mode working well with future potential:- background suppression- mass purification at REX TRAP- direct injection in to REX EBIS Details in the 2008 ISCOOL performance report by Dr. H. Franberg, Dr. Pierre Delahaye, et al. ISCOOL webpage: http://ab-div-op-iso-rfqcb.web.cern.ch/ Summary

  23. Special thanks to Hanna, Pierre and Tim The Isolde OP-team, AB/OP-PSB-isoAB/ATB, AB/VAC, AB/PO, AB/CO and Alexandre Dorsival (SC/RP) for making the ISCOOL 2008 run a success Thanks

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