1 / 33

IPM development for LIPAc

LIPAc: Linear IFMIF Prototype Accelerator. IPM development for LIPAc. P. Abbon, J.F. Denis, J. Egberts , J.F. Gournay, F. Jeanneau, J. Marroncle , J.P. Mols, T. Papaevangelou, H. Przybilski. J. Egberts’s PhD thesis defended on September 25 th , 2012 at Orsay (France)

beata
Download Presentation

IPM development for LIPAc

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. LIPAc: Linear IFMIF Prototype Accelerator IPM development for LIPAc P. Abbon, J.F. Denis, J. Egberts, J.F. Gournay, F. Jeanneau, J. Marroncle, J.P. Mols, T. Papaevangelou, H. Przybilski J. Egberts’s PhD thesis defended on September 25th, 2012 at Orsay (France) “IFMIF-LIPAc Beam diagnostics: Profiling and Loss Monitoring System” http://irfu.cea.fr/Documentation/Theses/ CERN Workshop on Non-Invasive Beam...

  2. Overview • IFMIF, LIPAc introduction • IPM prototype design, tests at GSI and Saclay • Space Charge effect • Design of large and medium IPM aperture • summary IPM: Ionization Profile Monitor CERN Workshop on Non-Invasive Beam...

  3. IFMIF (International Fusion Materials Irradiation Facility) International agreement of the BA (JAEA+F4E in Feb. 2007) = IFMIF + IFERC + JT60-SA IFMIF*: to test materials submitted to very high neutron fluxes for future Fusion Reactors. Test Cell Lithium Target 25 mm thick, 15 m/s L M H 2 cw accelerators, 2 x 125 mA, 2 x 5MW Beam profile 200 x 50 mm2 RFQ 5 MeV Flux ~ 1017 neutrons/s deuteron source 140/150 mA, 100 keV Superconductive Linac 40 MeV (Half Wave Resonators) • Typical reactions • 7Li(d,2n)7Be • 6Li(d,n)7Be • 6Li(n,T)4He CERN Workshop on Non-Invasive Beam...

  4. LIPAc(Linear IFMIF Prototype Accelerator) 12.5 kW 1125 kW 625 kW Validation phase: prototype accelerator ➝ LIPAc (Rokkasho – Japan) 100 keV 5 MeV 9 MeV Rokkasho • Injector delivery: March 2013 • RFQ commissioning: June 2015 Beam Dump ion source LIPAc = 125 mA cw, 9 MeV, 1.125 MW, RF 175 MHz Beam Extraction LEBT MEBT RFQ ScHWR-Linac HEBT • Very challenging Linear Accelerator: • highest intensity (125 mA) • highest beam power (1.125 MW) • highest space charge • very high radiation background, mainly due to neutron backscattered off the BD CERN Workshop on Non-Invasive Beam...

  5. LIPAc diagnostics Diagnostic- Plate Glossary: ACCT: AC Current Transformer BLoM: Beam Loss Monitor RGBLM: Residual Gas Bunch Length Monitor BPM: Beam Position Monitor DCCT: DC Current Transformer FC: Faraday Cup FFC: Fast Faraday Cup FCT: Fast Current Transformer IPM: Ionization Profile Monitor FPM: Fluorescence Profile Monitor µLoM: Micro Loss Monitor SEM Grids ACCT + DCCT Steerer for SEM IPM • 2 BPMs (stripline) • 2 Slits (Emittance) • RGBLM • 1 BPM (Stripline) FPM Emittance meter ∼ 20 BLoMs for the whole end-accelerator FC Species fraction measurement ACCT ACCT + FCT SEM Grids ACCT IPM 3 x 8 µLoM 4 grids analyser 4 Profilers (CCD camera) • 2 BPM • 3 BPM • 4 BPM (Stripline) 8 BPM (cryo) 1 Slit (E.spread) FPM CERN Workshop on Non-Invasive Beam...

  6. LIPAc IPMs Diagnostic- Plate Last HEBT part upstream to lead plug 2 IPMs BPM FPM viewport beam 1 IPM CERN Workshop on Non-Invasive Beam...

  7. IPM Prototype CERN Workshop on Non-Invasive Beam...

  8. IPM • Requirements, keeping in mind IFMIF • radiation hard materials ➞ neutrons: 7 kSv/h on beam axis at HEBT IPM location • fast FEE for monitoring beam footprint on the Li target • General aspect • Transverse size: 61 × 59 mm2 - depth 40 mm • 32 strips for charge collection (pitch = 1.25 mm ➞ 40 mm active width) • electric field uniformity ➞ Electric field simulation by FEM (SOLMAXP) • lateral degraders (150 MΩ) + 1 spire on top and bottom to reinforce the E-field homogeneity • movable slits in longitudinal direction for monitoring the active length of strips • typical applied voltage ∼ 5 kV ⇒ E = 833 V/cm spire SOLMAXP Degrader CERN Workshop on Non-Invasive Beam...

  9. Electric field: FEM simulation • Finite Element Method • SOLMAXP (R. Duperrier, CEA Saclay, Irfu/SACM) • Ex component (V/m) in the transverse plane of the IPM • no spire ➞ inhomogeneity < 30% • spire (copper loop) ➞ inhomogeneity < 3% inhomogeneity < 3% inhomogeneity < 30% J. Egberts – April 2010 CERN Workshop on Non-Invasive Beam...

  10. FEE & daq • Front End Electronics • transimpedance and logarithmic cards • ➞ continuously multiplexed every 2 µs, ie 1 strip ≡ 2000/32 = 62.5 ns • integration card (81 µs to 64 ms) • data Acquisition System • Acqiris card • ➞ 8 bits ADC • ➞ 1 GHz sampling rate with 2 MB memory Beam profile Trigger signal set on channel 16 2.1 s or 32 strips or 40 mm transimpedance card (oscilloscope ) CERN Workshop on Non-Invasive Beam...

  11. GSI tests, 2010 CERN Workshop on Non-Invasive Beam...

  12. GSI test • Tests on the UNILAC of GSI (X2 branch devoted to GSI diagnostic team) • ➞ May and November 2010 • ➞ examples of beam conditions: • 33 µA 48Ca10+ at 4.6 MeV/A @ 5ms/s • 1.6 mA 238U28+at 4.8 MeV/A @ 100 µs/s • ➞ Residual gas: adjustable pressure from 5 10-7 mbar to 5 10-5 mbar CERN Workshop on Non-Invasive Beam...

  13. Electric field uniformity (1) • Beam conditions are kept frozen • Stepper motor ➞accurate transversal displacement of the IPM • IPM ➞ calculation of the central position of the beam • Very good linearity (slope ∼ 1) • ⇒ Good electric field uniformity ∆disp.=500 µm Beam profile measured with the IPM ∆disp.=20 mm 1 mA Xe21+ ∆t=60 ms CERN Workshop on Non-Invasive Beam...

  14. Electric field uniformity (2) • Aperture variation of the sliding window • strip current rises linearly • weak σ enlargement • ⇒ due to field inhomogeneity or to tilted strips? Signal (mm.mV) sliding windows Aperture (mm) s t r i p s 30 mm slit aperture 40 mm • Conclusion: E field uniformity seems to be quite good on “inner” transverse plane CERN Workshop on Non-Invasive Beam...

  15. Accelerating field, Resolution, extrapolation • Accelerating Field • Profile width • electron profile much broader than ion profile • profile width decrease with higher voltages • Resolution • Fluctuation of beam center versus time acquisition (∆t) • σ << 100 µm for ∆t < 1 ms σ (mm) 120µA Xe21+, 10-5 mbar N2 Extrapolation GSI data to LIPAc ⇒ 8.4 mA with ∆t=5 ms at 5 10-8 mbar time integration (µs) CERN Workshop on Non-Invasive Beam...

  16. Profile comparison IPM / FPM Extracted from « GSI SCIENTIFIC REPORT 2010 » • At the same location (cross): • IPM on 1 port • FPM or BIF on a port at 90° • Note, walls were blackened to avoid reflection for CCD FPM: Fluorescence Profile Monitor BIF: Beam Induced Fluorescence CERN Workshop on Non-Invasive Beam...

  17. Saclay tests, 2010 CERN Workshop on Non-Invasive Beam...

  18. Silhi tests Picture taken from a viewport • Silhi source of Iphi • protons • dc: few 10-3 up to cw • Emax = 95 keV • Imax= 100 mA • P ~ 6 10-5 Torr Ibeam ~ 3 mA Silhi: Source of Light Ions at High Intensity Iphi: Injector of Protons at High Intensity IPM was able to handle CW beam up to 21 mA. CERN Workshop on Non-Invasive Beam...

  19. Space Charge effect (SC) CERN Workshop on Non-Invasive Beam...

  20. Space Charge effect Theoretical • Profile reconstruction with an algorithm • Ionization products experienced • IPM electric field • Beam electric field: Space Charge • ➞ GSI: low I ⇒ negligible effect • ➞ IPHI: high I, low E ⇒ big effect (profile distortion) • How to counteract SC • magnetic field for guidance ➞ no space available • increasing the electric field ➞ limitation due to deviation • applying correction with an algorithm (developed by Jan Egberts) SC off ∆max ≈ 0.3 mm ∆max ≈ 5 mm SC on CERN Workshop on Non-Invasive Beam...

  21. Space Charge Algorithm • 1- Hypothesis • D+ • round beam • beam charge distribution described by a generalized Gaussian Distribution (GGD) • Ibeam • 2- Approach • Matrix components Mij represent the probability that an ion collected on strip j has been create at the position i • ➞ beam distribution (GGD) & ions trajectories • Set of matrices computed for various parameter combinations • Ibeam: 1 to 125 mA ➞ 35 • σ: 5 to 15 mm ➞ 21 • β: -0.25 to 0.25 ➞ 3 • total matrices: 2205 • 3- First parameter to initiate iteration process • fit of the experimental profile using a GGD to extract • Ibeam: given by Current Transformers • ➞ σ0 = σexp • ➞ β0 = βexp • iterations • ∙∙∙ • until parameters converge (σn≈ σn-1 ; βn ≈ βn-1) ➞ self consistent solution • Generalized Gaussian distribution • µ: profile center • Two degrees of freedom • σ: 2nd moment • β: kurtosis, 4th moment CERN Workshop on Non-Invasive Beam...

  22. Large aperture IPM for HEBT CERN Workshop on Non-Invasive Beam...

  23. IPM: HEBT • Large aperture: 15 × 15 cm2 • Very high radiation background: 7 kSv/h neutrons on beam axis • ⇒ Materials:ceramics (RO4350B), copper, resistors (CMS), Kapton (ribbon cable) • + SAMTEC 80 micro coaxial cables (PVC, LCP, FEP ; halogen) • Degraders (16×2): 230 MΩ ➞ Lorentz-3D for electric field uniformity • FEE based on integrators; rate ≈ 10 Hz • HVmax = 16 kV • Tests done at Saclay on SILHIsource: Dec. 2011 - Feb. 2012 • proton Emax= 95 keV, Imax = 100 mA, dc: up to cw • Main test: SC algorithm • frozen beam characteristics (conditions) • only variation of extracting field HV: 1.65 to 6.5 kV 15×15 cm2 CERN Workshop on Non-Invasive Beam...

  24. IPM: HEBT (cable test) CERN Workshop on Non-Invasive Beam...

  25. Medium aperture IPM for Diagnostic-Plate CERN Workshop on Non-Invasive Beam...

  26. D-Plate: IPM • Medium aperture: 10 × 10 cm2 • Low radiation background • Degraders (13×2): 400 MΩ • FEE based on integrators; rate ≈ 10 Hz • HVmax = 19 kV • Tests on SILHI: in progress CERN Workshop on Non-Invasive Beam...

  27. 1st profile… CERN Workshop on Non-Invasive Beam...

  28. Summary • LIPAc is a challenging linear accelerator • ➞ high intensity, high power, high SC, high radiation background • IPM prototype have shown very good behavior • ➞ thanks to its good electric field uniformity (FEM simulation) • ➞ very nice profile agreement with FPM • Nevertheless it is very sensitive to SC effect • An algorithm to correct SC was developed and tested with promising results • One large aperture IPM (15 × 15 cm2) has been already tested • A medium aperture IPM (10 × 10 cm2) is in test progress. • IF IFmif… • ➞ the beam footprints on the Li target (20 × 5 cm2) would have to be monitored in a very harsh environment. • ➞ new materials and perhaps technics should have been inquired… • Very challenging issue! CERN Workshop on Non-Invasive Beam...

  29. Arigatou, merci… for your attention • Thanks to: • CEA Saclay colleagues • P. Abbon, J.F. Denis, J. Egberts, J.F. Gournay, F. Jeanneau, J.P. Mols, T. Papaevangelou, H. Przybilski • GSI diagnostics group and UNILAC GSI people • SILHI – IPHI group at CEA Saclay • Organizing committee of this WS for the invitation CERN Workshop on Non-Invasive Beam...

  30. Challenges PAP Nghiem – Beam dynamics – CEA Saclay • highest intensity (125 mA cw) • highest beam power • highest space charge • ⇓ • ↑ RFQ length to ↓ SC • for beam injection in the SRF Linac • ⇓ • longest RFQ (0.1 to 5 MeV) • ∼ 10 m • ⇓ • Validation Phase: LIPAc RFQ (5 MeV) LIPAc (9 MeV) CERN Workshop on Non-Invasive Beam...

  31. SC for Asymmetric beam • σx = 6 mm - σy= 9 mm • Search algorithm find profile with a σxreconstructed= 5.5 mm CERN Workshop on Non-Invasive Beam...

  32. IFMIF • Edeuteron = 40 MeV • Ibeam = 2 × 125 mA • HV = 12 kV • Assumption: • perfect electric field uniformity ➞ IPM with a large depth • beam cross section: 25 × 100 mm2 • ⇒ Space charge effect for IPM aperture: • 200 mm (left) • 300 mm (right) CERN Workshop on Non-Invasive Beam...

  33. Radiation background • Shielding (polyethylene disks, plates…) • ➟ neutrons • Fluence, calculated over 1 month cw CH2 – V shape 75 55 145 beam 125 105 45 axis 35 95 115 25 15 5 135 SRF Linac CH2 wall+roof 65 concrete BD 85 A. Marchix – January 2012 (only BD) • Electronic radiation hardness • high energy neutrons (~ MeV) ⇒ electronic trouble for Fluence > 1011 n/cm2 UNED (Madrid) - 2008 CERN Workshop on Non-Invasive Beam...

More Related