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Status MAMI facility

Status MAMI facility. KHUK-workshop , 30.11. 2012 Kurt Aulenbacher Institut für Kernphysik Uni Mainz. Outline. SFB 1044 and the operation of MAMI Prisma and erection of MESA. MAMI at IKP Mainz. 1.6 GeV c.w. polarized beam 150kW beam power. Operation statistics 2005 – Nov. 2012.

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Status MAMI facility

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  1. Status MAMI facility KHUK-workshop , 30.11. 2012 Kurt Aulenbacher Institut für Kernphysik Uni Mainz

  2. Outline • SFB 1044 and the operation of MAMI • Prisma and erection of MESA

  3. MAMI at IKP Mainz 1.6 GeV c.w. polarized beam 150kW beam power

  4. Operation statistics 2005 – Nov. 2012 average availability for users: 85% ! 72% 61% 46% 51% 40% 36% HDSM-operation 1% MAMI total (1991 – 2012): 129592 hours of operation

  5. MAMI at IKP Mainz • Operational highlights 2012: • A4- ”experiment • PV e-scattering on deuterium@200MeV • - KAOS chicane in high intensity operation

  6. MAMI beam time in 2012 (until November) Distribution between the experimental groups Operation for experiments of SFB 1044 will continue for (hopefully) many years

  7. PRISMA 15 June 2012: PRISMA excellence cluster is awarded to JGU • PRISMA includes construction of innovative particle acclerator • for hadron/particle physics experiments in the 100 MeV range • Mainz Energy recovering Superconducting Accelerator

  8. High power beam dump Experimental hall Access- shaft MESA-hall-2 MESA-hall-1 MAMI/MESA separation (shielding) MESA at IKP Mainz -no new buildings -MAMI experiments continue seperatly

  9. MESA acceleratorproject rationale • Experiments conceivable which require a new & innovative accelerator • low energy (100-200MeV)  therefore accelerator ‘affordable’ • MAMI acc. team competence represents basis for development • Project will be attractive for young students and researchers Make use of innovations in SRF accelerator science: • Energy recovery linac (ERL) • 2. Recent progress in high gradient-c.w.-SRF Beam parameter goals in two different modes of operation: 1.) EB-mode External spin-polarized c.w. beam at 200 MeV (Q2=0.005GeV/c at 30 degree). L>1039 cm-2s-1 2.) ERL-mode: 10mA at 100 MeV with L~1035 cm-2s-1

  10. PIT MESA-Scheme KEY: PS: Photosources: 100keV polarized (EB, ERL (low charge)), 500keV unpolarized (ERL, high charge) IN: 5 MeV – NC injector SC: 4 Superconducting cavities Energy gain 50 MeV per pass. 1-3 Beam recirculations for EB Orbit 1 common to ERL and EB, Orbit 2 could be separate for ERL and EB PIT: Pseudo Internal target (ER-experiment) PV: Parity violation experiment (EB-mode) DU: 5 MeV beam dump in ERL-mode MESA-LAYOUT Area:22*14m2 2ERL IN 1 2 3 SC PS Existing walls: 2-3m thick shielding RC EXPERIMENTAL BEAM PARAMETERS: 1.3 GHz c.w. EB-mode: 150 mA, 200 MeV polarized beam (liquid Hydrogen target L~1039) ERL-mode: 10mA, 100 MeV unpolarized beam (Pseudo-Internal Hydrogen Gas target, L~1035) DU to PV-experiment

  11. Accelerator Layout Design by Ralf Eichhorn (Deutscher Designpreis für Magnethochregallager) Alternative: Double axis acceleration a la CEBAF: more compact, but less flexible!

  12. Accelerator Layout PIT P2 V. Bechthold/R. Heine

  13. ERL-PIT-experiments 20s beam envelope for en=5mm H2 6mm dia beam in Dublett V. Tioukine Dublett Pump • Assuming target density N=2*1018 atoms/cm-2 (3.2 mg/cm2, 5*10-8 X0) • we have (at I0=10-2 A) luminosity of L= I0/e*N=1.2*1035cm-2s-1 • (average) ionization Energy loss: ~ 17eV •  RMS scattering-angle (multiple Coulomb scattering): 10mrad • single pass beam deterioration is acceptable Note: storage ring: beam emittance lifetime ~ 10milliseconds (stationary vs. variable background…) • beam halo & long tails of distribution due to Coulomb scattering have to be studied

  14. EB workhorse experiment : PVES at low Q (P2 experiment within SFB 1044)

  15. MESA-beam-parameters stage1/stage-2

  16. MESA- stage1 Timescale Accelerator basic design: end 2013 Early 2014: ordering SRF Early 2016 delivery End 2017 operation …Thank you!

  17. SRF-main accelerator issues 9 cell ‘TESLA’ (E-XFEL) p-mode structure: Q-curve often measured under not realistic ‘vertical’ conditions…esp. dustparticles & contamination films may appear during horizontal assembly, accidents in the vacuum system, etc…. New HIM-building Mainz: is planned to be equipped with a Clean room facility & high pressure (ultrapure) water rinsing (HPR) Problem for high c.w. current operation: HOM excitation PHOM~I2B

  18. A REAL SRF ‘module’ True c.w.-operation SRF facilities: CEBAF, ELBE, S-DALINAC (3GHz) not: E-XFEL, FLASH, TESLA/ILC. c.w. requires lowering the Gradient due to power dissipation! J. Teichert et al. NIMA 557 (2006) 239 Such modules can be ordered from industry. Missing: sufficient higher order mode damping for I>2-4 mA. Note MESA stage-2 ERL-current is 40mA!  modify after stage-1 or take the risk??

  19. Injector issues • Pro‘s for normal conducting injector: • no cryogenic load • considerably lower cost, established design, e.g. >9mA c.w. without BBU • (HOM excitation strongly suppressed) • high flexibility: variable beta-design is feasible! probably better beam quality than • existing SRF injectors GRP: Gun/rotator/ polarimeter (EB-mode) CBP: Chopper/buncher Preacc. (g-beta) HCI: 511keV high bunch charge injection (ERL-mode, stage-2) 2m, 2MeV at PHF=30kW 5MeV IN CBP HCI GRP DU PV SC RC

  20. Back-ups

  21. Spin polarized source layout Chop. buncher graded-b 550keV 3m Injection of 550kV high charge source Ө strongly influenced by need of ‘false’ asymmetry control! Afalse <0.2ppb Spin rotation axis Spin direction 2.5m ● f=p/2 f=p/2 DSP f=var GUN to second part ● Systematic electron optical helicity reversal! (similar to JLAB/QWEAK) from first part  tension with desire to have a SHORT injection for high charge  separate 550kV gun

  22. Spin rotation and source beam energy • 100kV Filter, L=0.3m • operated at 23kV over 2cm gap • not practical to handle filter at 500keV (g=2), … but could probably work at 200keV (200keV source is able to reach emittance goal at 7.7pC!) V. Tioukine, K.A. NIM A 568 537 (2006) JLAB development: A 200keV source is nowadays very compact - R. Suleiman et al. Proceedings ERL2011,

  23. Accelerator Layout arcs merger First Order beam optics for arcs, mergers & combiners

  24. Summary/Outlook • MESA: First ERL with particle physics experiments in Europe • Detailled considerations have begun for all subsystems • Superconducting Radiofrequency System and it‘s cryogenics • is main cost driver. • MESA funding is part of ‚PRISMA‘ excellence cluster req • ERL operation restricted so far to 1mA in order to save costs • for development and cryogenics of high current SRF sections (additional ~ 5 M€) • Great support from TU-Darmstadt, hope to continue collaboration • Mainz also collaborates with HZB (Berlin-Pro) &CERN (LHeC) • Photoinjectors collaborations with HZD (ELBE) and HZB • main issue now, after funding decision: creating a powerful team! • good reason to believe that stage-1 can be made operational within 5 years

  25. Backups

  26. WHY is source-emittance so important for ERL-experiments? 20s beam envelope H2 6mm dia Dublett Dublett Pump

  27. Emittance requiments An normalized emittance of 5 mm is the key for successful operation of DM-experiment With tbunch << taccel we have a lower limit for emittance at the cathode • But: vacuum space charge destroys beam emittance… • Countermeasures: • 1.) accelerate with high field to relativistic velocities because Fq~1/g2. • a) ERL-d.c guns ~3-6MV/m to 0.25-0.5 MeV • b) SRF gun with 15MV/m to ~ 5 MeV (FZD, future: BERLinPRO). • MESA –baseline for ERL-source: 200keV ‘inverted‘ Photogun a la JLAB (P. A. Adderley et al. PR-ST-AB 13 010101 (2010)) • +350keV electrostatic Postaccelerator (reduced Version of famous 2MeV d.c.-MAMI-A injector)

  28. SRF-main accelerator issues 9 cell ‘TESLA’ (E-XFEL) p-mode structure: Q-curve often measured under not realistic ‘vertical’ conditions…esp. dustparticles & contamination films may appear during horizontal assembly, accidents in the vacuum system, etc…. New HIM-building Mainz: is planned to be equipped with a Clean room facility & high pressure (ultrapure) water rinsing (HPR)

  29. A REAL SRF ‘module’ True c.w.-operation SRF facilities: CEBAF, ELBE, S-DALINAC (3GHz) not: E-XFEL, FLASH, TESLA/ILC. c.w. requires lowering the Gradient due to power dissipation! J. Teichert et al. NIMA 557 (2006) 239 Such modules can be ordered from industry. Missing: sufficient higher order mode damping for I>2-4 mA. Note MESA ERL-current is 40mA!

  30. Recirculator PV-Experiment 14m Dark photon-exp. • 200 MeV EB could require vertical stacking of 3fold recirculation • Merger Systems complicated due to limited space • But Magnets very small (compared to MAMI) • Beam power (EB) 30kW@200 MeV (ERL) 50kW at 5MeV •  R.f power needed EB ~ 120kW ERL ~ 140kW • 1300 MHz R.f. supplied by reliable & stable semiconductor amplifiers (not Klystrons!) • Experiments are TINY

  31. 405nm Laser • Advantage of 405 nm: KCsSb QE~30mA/Watt. Cost ~ 3k€/watt (d.c.); • optimum beam quality: 1mm dia-spot at 1m only with collimation tube! • electron gun current presently limited by power supply (<3mA) • Diode is well suited for pulsing at GHz-frequencies , (<40ps at full power) • Could provide ~1W (40ps, r.f. synchronized) for MESA (1 lifetime ‘overhead’) •  five DVD-player diodes in parallel! collimation tube Laser-out d.c or R.f 2cm €100 purchase from eBay Diploma thesis I. Alexander

  32. Lifetime issue Milliampere- test experiment with NEA-GaAs GaAs operation would be possible, but inconvenient • long lifetime required  KCsSb (unpolarized) photocathode • lifetime about 100 hours @25mA demonstrated recently at Cornell

  33. PCA fabrication chamber at Mainz-HIM PCA-Apparatus : • KCsSb technology available at Mainz • good results >30mA/Watt (>10% Q.E) • evidence for *100 stability increase with respect to GaAs (2000 hours at 10mA?)

  34. DM: Focusing through the PIT

  35. DM: Focusing through the PIT 20s beam envelope H2 6mm dia E0=104MeV Dublett Dublett Pump • Assuming target density N=2*1018 atoms/cm-2 (3.2 mg/cm2, 5*10-8 X0) • we have (at I0=10-2 A) luminosity of L= I0/e*N=1.2*1035cm-2s-1 • (average) ionization Energy loss: ~ 17eV •  could allow to recuperate more energy than in conventional ERL (2.5MeV). • RMS scattering-angle (multiple Coulomb scattering): 10mrad • single pass beam deterioration is acceptable Note: storage ring: beam emittance lifetime ~ 10milliseconds (stationary vs. variable background…) • beam halo & long tails of distribution due to Coulomb scattering have to be studied

  36. MESA-experiments-3: Applied physics High beam power electron beam may be used for: • ERL-mode: Production of NV-nanodiamonds (e.g. medical markers) • EB-mode: High brightness source of cold (polarized) positrons • G. Werth et al. : • Appl. Phys. A 33 • 59 (1984) • MESA can produce ~109 positrons/s in a beam of <1cm diameter at 120eV • surface science: magnetic structures • positronium production Color: NV-centers introduced in Diamond. Irradiated at MAMI for 3 days, 50mA at 14MeV (J. Tisler et al. ACS NANO 3,7 p.1959 (2009))

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