1C. CavataBENE 17/03/05 Proton driver Saclay A talk assembled with materials from R. Gobin P.Y. Beauvais B. Visentin R. Duperrier Outlines A.ECR H - source B.NC RFQ C.SuperConducting Cavities D.Code/Simulation of Space Charge

C. Cavata2 BENE 17/03/05 Proton LINAC : Overall Design SPL EUROTRANS CW or Pulsed LINAC Niobium Superconducting Cavities Spoke Elliptical QWR

C. Cavata3 BENE 17/03/05 Proton Driver Saclay H - Electron Cyclotron Resonance Source

4C. CavataBENE 17/03/05 Rectangular plasma chamber 5 mm extraction aperture ECR zone at RF entrance Operation : Pulsed mode Energy 10 kV Technical options A new source based on ECR plasma A 2.5 GHz design Main Goal is reliability Aim : for high power accelerators, H - current of a few tens of mA at 50 to 100 kV A new H - source based on ECR plasma

5C. CavataBENE 17/03/05 H - production A/ Plasma H 2 → H + + e - ; H 2 +e - (a few 10 eV) → H 2 * +e - B/ Dissociation H 2 * +e - (eV) → H - +H Installation of a stainless steel grid in the rectangular plasma chamber

6C. CavataBENE 17/03/05 Grid position I H - from few µA to nearly 100 µA Grid polarization I H- from 100 µA to nearly 1mA First Optimisations: H - production

7C. CavataBENE 17/03/05 H - gain confirmation To prove effective H - ions production analysis with a dipole magnet ?

8C. CavataBENE 17/03/05 latest results the extracted H- current increased up to 1.25 mA at 10kV. And after parameter optimisations, the extracted beam reached close to 4 mA at 10kV. Reflected RF power H- beam, 0.5mA/cc and 0.5ms/cc The source is running at lower pressure To increase the e - density in the plasma generator zone, Boron Nitride plates have been installed on the copper walls …

9C. CavataBENE 17/03/05 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

C. Cavata10 BENE 17/03/05 Proton Driver Saclay 3 MeV NC RFQ

C. Cavata11 BENE Saclay Set up of a 3 MeV – 100 mA proton beam a.ECR Source (SILHI) b.3 MeV 352 MHz RFQ c.Diagnotics d.Dump

12C. CavataBENE 17/03/05 A scale 1 Aluminium model of the RFQ

13C. CavataBENE 17/03/05 provisional assessment of the first (1/6) RFQ Section Acceptable Leaking level : 5, Pa. m 3. s -1 Positive RF Tests First (1/6) RFQ section validated

14C. CavataBENE 17/03/05 RF power RF installed, Waveguides connected to the 1.3 MW loadRF installed, Waveguides connected to the 1.3 MW load Cooling set up finalized (1MW in Cu)Cooling set up finalized (1MW in Cu) RF Tests on load to begin soon RF Tests on load to begin soon

15C. CavataBENE 17/03/05 Diagnostics Wire scanner and BPM installed in the LEB section and tested with SILHI (H + ) Beam (100 keV 100 mA)

16C. CavataBENE 17/03/05 Beam dump (300 kW) Design done : Nickel

17C. CavataBENE 17/03/05 Planning RFQ June 2007?

C. Cavata18 BENE 17/03/05 Proton Driver Saclay Superconducting Cavities

C. Cavata19 BENE 17/03/05 Proton LINAC : Overall Design SPL EUROTRANS CW or Pulsed LINAC Niobium Superconducting Cavities Spoke Elliptical QWR

C. Cavata20 BENE 17/03/05 Quarter Wave Resonator 88 MHz  = 0.07 Design, Manufacturing, Chemistry, Assembly RF Tests in vertical cryostat at Saclay Intermediate Acceleration SRF Workshop – G. Devanz et al. (July 2005)

C. Cavata21 BENE 17/03/05 High Energy : Low-  Design and Manufacturing of Low-  Elliptical Cavity ( 5-cell 700 MHz  = 0.47 ) SRF’2005 Workshop – G. Devanz et al. Cold Tuning System and High Power Coupler ( 1 MW pulsed mode ) Cavity expected at Saclay mid-2006 Mutual interest with CARE/SRF

C. Cavata22 BENE 17/03/05 Nb Cavity ( CEA Saclay / IPN Orsay ) 5-cell 700 MHz  = 0.65 LINAC’2004 – B. Visentin et al. Design, Manufacturing, Chemistry, Assembly RF Tests in vertical and horizontal cryostat ( Cry-Ho-Lab ) at Saclay High Energy : Medium- 

C. Cavata23 BENE 17/03/05 Technological Infrastructures ( Chemistry – Clean Room – CryHoLab ) at Disposal for European Collaborations 5-cell elliptical cavity 3-spoke Cavity Jülich

C. Cavata24 BENE 17/03/05 Technological Infrastructure at Saclay Chemistry High Pressure Rinsing Clean Room (class 100) Vertical Cryostats Horizontal Cryostat Cry-Ho-Lab RF Power Klystron – IOT 1300 – 700 MHz

C. Cavata25 BENE 17/03/05 Triple-Spoke Niobium Cavity ( FZ - Jülich ) 784 MHz  = 0.2 Saclay contribution : Inner Surface Chemistry ( 100  m removed ) High Pressure Rinsing Assembly in Clean Room (class 100) Transport to FZ Juelich (under vacuum) Intermediate Acceleration

C. Cavata26 BENE 17/03/05 Low-  Niobium Cavity ( INFN Milan ) 5-cell 700 MHz  = 0.47 EPAC’2004 – A. Bosotti et al. Chemistry, Assembly and RF Test in vertical cryostat at Saclay Near future : Test in CryHoLab High Energy

C. Cavata27 BENE 17/03/05 Proton Driver Saclay Software

28C. CavataBENE 17/03/05 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

29C. CavataBENE 17/03/05 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)

30C. CavataBENE 17/03/05 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)

31C. CavataBENE 17/03/05 More ?

32C. CavataBENE 17/03/05 protons Fraction of SCC Source SILHI (H + ) and the Low Energy Beam Measurement of the Space Charge Conpensation (A.Benismail PhD) Emitance measurements

33C. CavataBENE 17/03/05 RF coupling for the RFQ The.Los Alamos scheme (LEDA) Is not optimal A /4 transition is being tested. Preliminary resulsts are promising

34C. CavataBENE 17/03/05 Beam neutralization principle potential well residual gas (H 2 ) in the beam transport line Electrical neutralization is performed by e - trapping in the potential well of the beam. H 2 + ions are repelled to the pipe Let's consider a 100 mA proton 100 keV in a LEBT electrical field Production of e - and H 2 + ions by ionization of residual gas p + H 2 p + e - + H 2 +

35C. CavataBENE 17/03/05 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.

36C. CavataBENE 17/03/05 Beam neutralization: DC proton beam in a drift Observed by R. Baartman and D. Yuan, "Space-Charge Neutralization Studies of an H- Beam", EPAC88.

37C. CavataBENE 17/03/05 ECR source modelization 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,... WHY?

38C. CavataBENE 17/03/05 ECR source: the basics Permanent magnets Coils plasma RF Extraction

39C. CavataBENE 17/03/05 Examples of simulations These first simulations show that the chamber geometry may impact on the source performances. Ey in plasma chamber Ez Ey TE 10 mode is injected Cylindrical box Rectangular box

40C. CavataBENE 17/03/05 Code benchmarking