Proton driver activities @ Saclay

1. Proton driver activities @ Saclay • A talk assembled with materials from • R. Gobin • P.Y. Beauvais • B. Visentin • R. Duperrier • Outlines • ECR H- source • NC RFQ • SuperConducting Cavities • Code/Simulation of Space Charge

2. Proton LINAC : Overall Design Niobium Superconducting Cavities Elliptical Spoke QWR CW or Pulsed LINAC SPL EUROTRANS

3. Proton Driver Activities @ Saclay H- Electron Cyclotron Resonance Source

4. Technical options Rectangular plasma chamber 5 mm extraction aperture ECR zone at RF entrance Operation : Pulsed mode Energy 10 kV A new H- source based on ECR plasma Aim : for high power accelerators, H- current of a few tens of mA at 50 to 100 kV A new source based on ECR plasma A 2.5 GHz design Main Goal is reliability

5. H- production A/ Plasma H2 → H+ + e- ; H2+e- (a few 10 eV) → H2*+e- B/ Dissociation H2*+e- (eV) → H-+H Installation of a stainless steel grid in the rectangular plasma chamber

6. H- production Grid position I H- from few µA to nearly 100 µA Grid polarization I H-from 100 µA to nearly 1mA First Optimisations:

7. H- gain confirmation ? To prove effective H- ions production analysis with a dipole magnet

8. latest results H- beam, 0.5mA/cc and 0.5ms/cc Reflected RF power To increase the e- density in the plasma generator zone, Boron Nitride plates have been installed on the copper walls … And after parameter optimisations, the extracted beam reached close to 4 mA at 10kV . the extracted H- current increased up to 1.25 mA at 10kV. The source is running at lower pressure

9. Future plans • New magnetic configuration • Magnetic coils will be replaced by permanent magnet rings • A new cylindrical water cooled plasma chamber • more suitable for the next magnetic configuration • possibility of working in long pulse mode • Far future •  change the RF generator frequency (10 GHz) to improve the plasma density Aim : for high power accelerators, H- current of a few tens of mA at 50 to 100 kV

10. Proton Driver Activities @ Saclay 3 MeV NC RFQ

11. @ Saclay • Set up of a 3 MeV – 100 mA proton beam • ECR Source (SILHI) • 3 MeV 352 MHz RFQ • Diagnotics • Dump

12. A scale 1 Aluminium model of the RFQ

13. provisional assessment of the first (1/6) RFQ Section • Acceptable Leaking level : 5,65. 10-10 Pa. m3. s-1 • Positive RF Tests • First (1/6) RFQ section validated

14. RF power • RF installed, Waveguides connected to the 1.3 MW load • Cooling set up finalized (1MW in Cu) • RF Tests on load to begin soon 04-2005.

15. Diagnostics Wire scanner and BPM installed in the LEB section and tested with SILHI (H+) Beam (100 keV 100 mA)

16. Beam dump (300 kW) Design done : Nickel

17. June 2007? Planning RFQ

18. Proton Driver Activities @ Saclay Superconducting Cavities

19. Proton LINAC : Overall Design Niobium Superconducting Cavities Elliptical Spoke QWR CW or Pulsed LINAC SPL EUROTRANS

20. Intermediate Acceleration Quarter Wave Resonator 88 MHz b = 0.07 Design, Manufacturing, Chemistry, Assembly RF Tests in vertical cryostat at Saclay SRF Workshop – G. Devanz et al. (July 2005)

21. High Energy : Low-b Design and Manufacturing of Low-b Elliptical Cavity ( 5-cell 700 MHz b = 0.47 ) Cold Tuning System and High Power Coupler ( 1 MW pulsed mode ) Cavity expected at Saclay mid-2006 Mutual interest with CARE/SRF SRF’2005 Workshop – G. Devanz et al.

22. High Energy : Medium-b Nb Cavity ( CEA Saclay / IPN Orsay ) 5-cell 700 MHz b = 0.65 Design, Manufacturing, Chemistry, Assembly RF Tests in vertical and horizontal cryostat ( Cry-Ho-Lab ) at Saclay LINAC’2004 – B. Visentin et al.

23. 5-cell elliptical cavity 3-spoke Cavity Jülich Technological Infrastructures ( Chemistry – Clean Room – CryHoLab ) at Disposal for European Collaborations

24. Technological Infrastructure at Saclay Clean Room (class 100) High Pressure Rinsing Chemistry Cry-Ho-Lab Vertical Cryostats RF Power Klystron – IOT 1300 – 700 MHz Horizontal Cryostat

25. Intermediate Acceleration Triple-Spoke Niobium Cavity ( FZ - Jülich ) 784 MHz b = 0.2 • Saclay contribution : • Inner Surface Chemistry ( 100 mm removed ) • High Pressure Rinsing • Assembly in Clean Room (class 100) • Transport to FZ Juelich (under vacuum)

26. High Energy Low-b Niobium Cavity ( INFN Milan ) 5-cell 700 MHz b = 0.47 Chemistry, Assembly and RF Test in vertical cryostat at Saclay Near future : Test in CryHoLab EPAC’2004 – A. Bosotti et al.

27. Proton Driver Activities @ Saclay Software

28. Development and commercialization of codes During the last decade, Saclay has developed several codes which form now a complete package to design a linac architecture and to simulate the beam behaviour in a linac: • Design codes • Transport codes

29. Dissemination These codes are used by international labs: • RAL (UK) • CERN • IPNO, LPSC, GANIL, (FRA) • JAERI (JAP) • GSI, IAP, FZJ (D) • INFN (ITA) • MSU, ORNL, LBNL, LANL (USA) • CAT (INDIA) and companies: • HITACHI (JAP) • AES (USA)

30. CARE participation In the High Intensity Pulsed Proton Injector (HIPPI) JRA framework, these SW are used for : • investigations on the beam neutralization effect • modelization of an ECR ion source • participation to the code benchmarking with other european labs (GSI, RAL, IAP Frankfurt)

31. More ?

32. protons Source SILHI (H+) and the Low Energy Beam • Measurement of the Space Charge Conpensation (A.Benismail PhD) • Emitance measurements Fraction of SCC

33. RF coupling for the RFQ The .Los Alamos scheme (LEDA) Is not optimal A l/4 transition is being tested. Preliminary resulsts are promising

34. Beam neutralization principle Let's consider a 100 mA proton beam @ 100 keV in a LEBT electrical field potential well residual gas (H2) in the beam transport line Production of e- and H2+ ions by ionization of residual gas p + H2 p + e- +H2+ Electrical neutralization is performed by e-trapping in the potential well of the beam.H2+ ions are repelled to the pipe

35. Beam neutralization: background • People (including us) use to simulate the beam dynamic with full space charge or, sometimes, without space charge assuming a perfect neutralization (each proton is married to an e-). • But experiments and some theoretical analysis showed that the situation is more complex. • The beam charge may be partially compensated and the neutralizing distribution is not similar to the beam one. • This may lead to emittance growth. • The transcients may be problematic for pulsed machines. • We aim to study this topic using a PIC code (Cartago) in a first approach, in 2D (XY and RZ). Collisions MUST be included to refine the predictions for the equilibrium.

36. Observed by R. Baartman and D. Yuan, "Space-Charge Neutralization Studies of an H- Beam", EPAC88. Beam neutralization: DC proton beam in a drift

37. ECR source modelization WHY? • Loss predictions of beam dynamics codes are very sensitive to input distributions. • A better optical quality at the beginning of the injector increases the efficiency and simplifies the strategy for the implementation of collimators. • We can dream also to increase the performances in term of reliability, rise time, ...

38. ECR source: the basics RF plasma Permanent magnets Coils Extraction

39. Examples of simulations Ey in plasma chamber Ez TE10 mode is injected Ey Rectangular box Cylindrical box These first simulations show that the chamber geometry may impact on the source performances.

40. Code benchmarking