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R&D for Future Accelerators at IFIC

This project focuses on the development of beam instrumentation and optics design for future accelerators, including non-linear dynamics studies and new instrumentation techniques. The team at IFIC is conducting simulations and experiments to understand the effect of non-linear magnetic fields on beam emittance growth.

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R&D for Future Accelerators at IFIC

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  1. R&D for Future Accelerators at IFIC Scientific Staff: A. Faus-Golfe, C. Alabau, J.J. García, S. Verdu, J. Alabau Technical Staff: J.V. Civera, C. Blanch GDE Meeting Madrid

  2. Capabilities BEAM INSTRUMENTATION : BEAM DYNAMICS EXPERTISE: • Optics design • Non-linear dynamics studies • New instrumentation techniques • Commissioning - CALCULATION • Electromagnetic analysis • Electric circuits & electronics • Mechanical analysis - PROTOTYPING • Design: tooling, drawings • Fabrication follow-up • Assembly • Testing 3-D modellingot BPM Optics study for LHC non-linear collimation sysytem GDE Meeting Madrid

  3. Main ongoing projects • ATF-ATF2:Beam dynamic studies and commissioning of the EXT line (LAL,KEK,SLAC) • CLIC-CTF3:BPM’s for TBL (UPC, CERN) Pieces of BPM-TBL for CTF3 GDE Meeting Madrid

  4. ATF and ATF2 ATF was built in KEK (Japan) to create small emittance beams. The Damping Ring of ATF has a world record of the normalized emittance of 3x10-8 m rad at 1.3 GeV. ATF2 is being built to study the feasibility of focusing the beam into a nanometer spot (40 nm) in a future linear collider. Extraction line drives the beam from ATF to ATF2 GDE Meeting Madrid

  5. ATF and ATF2: the Extraction Line Extraction Line Beam extraction process The Extraction Line (EXT) drives the beam from the ATF DR to the ATF2 Final Focus beam line - Shared magnets with the DR - The beam passes off-axis diagnostic section extraction GDE Meeting Madrid

  6. ATF and ATF2: Emittance growth in the EXT line Since several years, the vertical emittane measured in the diagnostic section of the EXT line is significantly larger than the emittance measured in the DR and present a strong dependence with the beam intensity. Hypothesis The beam experiences some non-linear magnetic fields while passing off-axis through the shared magnets. GDE Meeting Madrid

  7. ATF and ATF2: Non-linear magnetic fields in the shared magnets of the EXT line Non-linearity of the magnetic field of the shared magnets: QM6, QM7, BS1X, BS2X, BS3X In order to quantify the effect of the non-linearity of the magnetic field on the extracted beam, the computation of the magnetic field on a finite mesh has been done with the code PRIAM. Polynomial fit with the code MINUIT in order to get a continuous representation of the magnetic field: Multipole MAD coefficients: GDE Meeting Madrid

  8. ATF and ATF2: Non-linear magnetic fields in the shared magnets of the EXT line Non-linearity of the magnetic field of the QM6 quadrupole Dipole component 0.008% Quadrupole component -0.03% Zone of interest for tracking x=0.0065m y =0m GDE Meeting Madrid

  9. ATF and ATF2: Non-linear magnetic fields in the shared magnets of the EXT line Non-linearity of the magnetic field of the QM7 quadrupole Dipole component -2% Quadrupole component -24% Zone of interest for tracking x=0.022 m y=0m GDE Meeting Madrid

  10. ATF and ATF2: Non-linear magnetic fields in the shared magnets of the EXT line Non-linearity of the magnetic field of the BS1X septum magnet Dipole component -1.5% Quadrupole component small Sextupolar component small BS2X (x=0.0153m , y=0m) and BS3X (x=0.016m , y=0m) more linear part GDE Meeting Madrid Zone of interest for tracking x=0.0855m, y=0m

  11. ATF and ATF2: Tracking simulations including non-linearfields in differentmagnets of EXT line Tracking performed with MAD and PLACET without horizontal bumps GDE Meeting Madrid

  12. ATF and ATF2: Tracking simulations for different x/y bump amplitudes GDE Meeting Madrid

  13. ATF and ATF2: ExperimentalProposal Beam size after the shared magnets is correlated with the emittance: - OTR monitor recently installed images the beam angular spread out of QM7 - Creating bumps in QM7 to probe effects on the vertical emittance - Measure beam sizes at the DR (XSR monitor) and the EXT line (OTR monitor) as a function of the bump amplitude offset in QM7 open the bump in DR and EXT close the bump in the DR OTR monitor

  14. ATF and ATF2: Experimental Work (Dec’07-May’08) Vertical beam size vs vertical bump amplitude at QM7 Damping Ring (XSR monitor) Extraction Line (OTR monitor) OTR/XSR (Measurements 19th Dec’07)

  15. ATF and ATF2: Experimental Work (Dec’07-May’08) • Simulations: • including non-linear fields in different magnets • for different horizontal bump amplitudes in QM7 (nominal extraction 22.5 mm) • with the input emittances the corresponding to the measured during the shift Measurements 19th Dec 2007 Measurements 28th May 2008 y=36 pm ~ 3*y,nom x=2.4 nm ~ 2*x,nom y=24.0 pm ~ 2*y,nom x=2.28 nm ~ 1.9*x,nom σy increase at the OTR as a function of the y bump amplitude

  16. ATF and ATF2:Conclusions The non-linear content of: QM6, QM7and BS1X has been calculated with PRIAM. Tracking simulations including non-linear field errors in: QM6, QM7 and BS1X shared by both the ATF EXT line and its DR, and orbit displacements from the reference orbit in the extraction region predict a vertical emittance growth of the extracted beam. Simulations show that the non-linear fields are very sensitive to the extraction position. The more important source on non-linearity is QM7. Recently, measurements using closed orbit bumps in the DR to probe the relation between the extraction trajectory and the emittance growth in the EXT line have been carried out. The results shows an emittance growth with a strong dependence with the extraction position. Both horizontal and vertical positions of the beam in the extraction region have to be controlled to avoid this emittance growth. Based in this work QM7 will be replaced from the EXT line by a magnet with large bore to avoid the non-linear field impact. GDE Meeting Madrid

  17. CLIC:The Compact Linear Collider Each sub-system pushes the state-of-the art in accelerator design The peak RF power required to reach the electric fields of 100 MV/m amounts to about 275 MW per active meter of accelerating structure. Not possible with klystrons. Hence a novel power source, an innovative two-beam acceleration system, in which another beam, the drive beam, supplies energy to the main accelerating beam. GDE Meeting Madrid

  18. CTF3: The CLIC Test Facility 3 • To demonstrate the two-beam acceleration scheme • A scaled facility for one branch of the Drive Beam Generation System of CLIC Layout of the CLIC EXperimental area (CLEX) building with TBL GDE Meeting Madrid

  19. TBL: The Test Beam Line 16 TBL Cells • The main aims of the TBL: • Study and demonstrate the technical feasibility and the operability a drive beam decelerator (including beam losses), with the extraction of as much beam energy as possible. Producing the technology of power generation needed for the two-beam acceleration scheme. • Demonstrate the stability of the decelerated beam and the produced RF power by the PETS. • Benchmark the simulation tools in order to validate the corresponding systems in the CLIC nominal scheme. GDE Meeting Madrid

  20. TBL + BPM Specifications • Main features of the Inductive Pick-Up (IPU) type of BPM: • less perturbed by the high losses experienced in linacs; • the total length can be short; • it generates high output voltages for typical beam currents in the range of amperes; • calibration wire inputs allow testing with current once installed • broadband, but better for bunched beams with short bunch duration or pulse IPU type of BPM suitable for TBL 2 BPS prototypes design and constructedat IFIC (scaled version of IPU DBL of CTF3) GDE Meeting Madrid TBL beam time structure

  21. BPS Mechanical Assembly PCB plates Ferrite cylinder Cooper body Vacuum assembly: ceramic tube with Kovar collars at both ends, one collar TIG welded to the downstream flange, and the other one electron welded to a bellow and a rotatable flange (~10-10 mbar l/s High Vacuum) GDE Meeting Madrid

  22. BPS Basic Sensing Mechanism Primary transformer electrode Longitudinal cross-section view • Four Outputs (V+,V-, H+,H-) with two Calibration inputs (Cal+, Cal-) • Difference signals (Δ) normalized to sum signal (Σ) (proportional to beam position coordinate) • xVα ΔV /Σ Vertical plane • xHα ΔH /ΣHorizontal plane • where: ΔV ≡(V+ − V-);ΔH ≡(H+ − H−); • Σ≡(V+ + H+ + V− + H- ) GDE Meeting Madrid

  23. BPS Frequency Response Induced current/signal Pulse deformation τdroop =1/ ωlow and τrise =1/ωhigh to let pass the pulse without deformation (droop time very important for ADC sampling) ωlow = R/L or flow = R/ 2𝜋L ωhigh = 1/RCS orfhigh = 1/2𝜋RCS τdroop ~ 102tpulse τrise ~ 10-2tpulse GDE Meeting Madrid

  24. BPS Electric Model Cut-off Frequencies: fLS = (RP+RC)/2𝜋LS fLD = (RP+RC)/2𝜋LD fhigh = 1/2𝜋ReCS • Highcut-off frequency: Fixedbysecondary Csforall cases • Lowcut-off frequencies: • Centeredwire: Balancedwallimagecurent • Displaced wire: Unbalancedwallimagecurrent(lowfrequencycoupling) GDE Meeting Madrid

  25. BPS Electronic Design GDE Meeting Madrid

  26. BPS Electronic Design Characteristic Output Signal Levels: PCBs Schematics and Output relation For a beam current of: IB = 30A Σ = 16.5 V outputs sum Vsec = Σ /4 = 4.125V centered beam ||ΔV||max = ||ΔH||max = Σ /2 = 8.25V beam at electrodes Vsec = (Σ/IB) Ielec with:(Σ /IB)= (RLoadRS1/(RS1+RS2+RS1)N) = 0.55Ω for design values: RLoad = 50 Ω, RS1 = 33 (13) Ω, RS2 = 18 (0)Ω(Ver. 2) N = 30 turns GDE Meeting Madrid

  27. BPS Readout Chain Digitizer/ADC developed at LAPP(Annecy) Amplifier developed at UPC Both designs must be rad-hard GDE Meeting Madrid

  28. carried out during several short stays at CERN, in the AB/BI-PI[1], where the wire testbench is placed, and it has been previously used for testing and calibrating BPMs for the Drive Beam Linac (DBL) of the CTF3. BPS Characterization Tests (Wire-Test) Sensitivity, Linearity and Frequency response Tests carried out during several short stays at CERN, in the AB/BI-PI* Labs. Testbench used to characterize the BPMs for the Drive Beam Linac (DBL) of the CTF3 Accelerator an Beams Department/ Beam Instrumentation Group – Position and Intensity Section GDE Meeting Madrid

  29. BPS: Sensitivity test (Ver. 1) Sensitivity Electric Offset Linear fit equations Sensitivity for V,H planes Electric Offset for V,H planes EOSV= (0.03±0.01) mm SV = (41.09±0.08)10−3 mm−1 SH = (41.53±0.17)10−3 mm−1 EOSH = (0.15±0.02) mm GDE Meeting Madrid

  30. BPS: Linearity test (Ver.1) Linearity errorOverall Precision/Accuracy Typical S-shape σH = 170 μm σV = 78 μm BPS above specs: σTBL < 50μm • Low current in the wire (13 mA) vs beam 32 A • Misalignment in the horizontal electrodes GDE Meeting Madrid

  31. BPS: Frequency Response test (Ver.1) Output electrodes ΔV, ΔH and Σ Wire Pos: Center Coupling at low frequency (no beam variation) Wire Pos:+8mm V,H Bandwidth specs: 10KHz-100MH tpulse=140ns Cut-off frequencies: fhigh > 100 MHz τrise < 1.6 ns fLΣ = 1.76 KHz τdroop Σ = 90ms fLΔ ≡ fLΔH = fLΔV = 282KHz τdroop Δ = 564ns GDE Meeting Madrid

  32. BPS: Pulse Response and Calibration (Ver.1) fLΔ[cal] =180 KHz < fLΔ=282 KHz (difference is about 100 KHz) τdroop Δ = 564 ns Represents a problem for the amplifier compensation in the Δ channels (lower fLΔ), because the same compensation designed for the fLΔ will be applied when exciting the calibration inputs to fLΔ[Cal] (bad pulse forcalibration ,overcompensation) τdroop Σ = 90 μs τdroop Σ [Cal] = 90 μs Compensationfrequency at theloweronefLΔ[Cal]gives a calibration pulse goodflatness and wire-beam pulse flat enoughfor TBL pulse duration τdroop Δ [cal] = 884 ns GDE Meeting Madrid

  33. BPS: Characterization Table (Ver.1) GDE Meeting Madrid

  34. BPS: Conclusions • A set of two BPS prototypes with the associated electronics were designed and constructed. • Theperformedtestsyield: • Good linearity results and reasonably low electrical offsets from the mechanical center. • Good overall-precision/accuracy in the vertical plane considering the low test current; and, a misalignement in the horizontal plane was detected by accuracy offset and sensitivity shift. • Low frequency cut-off for Σ/electrodessignals, fLΣ, and highcut-off frequency,fhigh, underspecifications. • Low frequency cut-off for Δsignals, fLΔ, determined to perform the compensation of droop time constant, τdroopΔ, with the external amplifier. GDE Meeting Madrid

  35. BPS: Future Work • Open issues for improvement in the BPS2 monitor prototype: • correct the possible misalignments of the horizontal plane electrodes suggested in the linearity error analysis • check if overall-precision below 50μm (under TBL specs), withenoughwirecurrent New wire testbench at IFIC • study the different low cut-off frequencies in the calibration, fLΔ[Cal], and wire excitation cases, fLΔ • Test Beam of the BPS1 in theTBLResolution at maximumcurrent. • BPS series production and characterization (15 more units). The new wiretestbenchwillallowhighercurrents, accurate (anti-vibration and micro-movementsystem) and automatizedmeasurements. GDE Meeting Madrid

  36. BPS: Future Work Sketch of new IFIC WireTestbench(underconstruction) x/y range 50x50 mm Resolution 0.1 mm Precision 0.7 mm GDE Meeting Madrid

  37. ATF-ATF2:Beam Instrumentation design and construction: • BPM’s supports with micromovers for FONT4 (KEK, JAI) • multi OTR (KEK, SLAC) • ILC: BDS instrumentation studies • LHC:non-linear collimation options for sLHC (SPS experiments) (EUCARD) • IFIMED:Imaging and Accelerators applied to Medicicine • Monitoring of secondary beams (beam position and size) (CERN; LLR, CNAO) • Cyclinacs applications (TERA, CTF3)CABOTO: Carbon Boster for Therapy in Oncology Main Future projects GDE Meeting Madrid

  38. ThanksforyourAttention GDE Meeting Madrid

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