1. H. Haseroth July 26 – August 1, 2004 NuFact04, Osaka 1 The 3 MeV H - Test Stand at CERN - The first part of the SPL - H. Haseroth on behalf of the SPL Study Group (Prepared by Carlo Rossi)

2. H. Haseroth July 26 – August 1, 2004 NuFact04, Osaka 2 The 3 MeV H - Test Stand at CERN OUTLINE The long term SPL project: motivation for a 3 MeV Test Stand. The intermediate Linac4 phase: a valuable improvement of the CERN proton accelerator complex. The 3 MeV Test Stand: a short term study tool and the future SPL Front End. Status and Planning.

3. H. Haseroth July 26 – August 1, 2004 NuFact04, Osaka 3 SPL: a long term project A multi-MW superconducting linac could simultaneously satisfy the needs of many users. Especially relevant are the potential applications* for:  Radio-active ions  Neutrinos: super-beam/beta-beam/neutrino factory  LHC: potential to increase the brightness and intensity beyond the ultimate beam. The challenge for high beam power is mostly coming from the control of beam halo. The control starts from the low energy end. A test bench for beam dynamics studies (including beam halo) is a must. *Debated at the workshop on “Physics with a multiMW Proton Source”, CERN, May 25-27, http://physicsatmwatt.web.cern.ch/physicsatmwatt/

4. H. Haseroth July 26 – August 1, 2004 NuFact04, Osaka 4 SPL block diagram (CDR 1) Linac 4: up-to-date design Superconducting linac: CDR 1

5. H. Haseroth July 26 – August 1, 2004 NuFact04, Osaka 5 Linac4: a mid-term phase Linac4 is the room-temperature section of the SPL (extended to 160 MeV), intended to upgrade the injection into the PS Booster. It allows for a significant performance improvement for the present users like LHC and ISOLDE, at a limited cost. Standard operation Linac 4 Basic user’s request CNGS flux [  10 19 pot/year]4.7 (4.5)7.5 (4.5)4.5 FT spills [  10 5 /year]3.2 (3.4)3.3 (5.6)7.2 East Hall spills [  10 6 /year]1.5 1.3 NTOF flux [  10 19 pot/year]1.6 1.5 ISOLDE flux [μA] [nb. of pulses/hour] 3.1 2200 6.4 2240 1.9 1350 72 bunch train for LHC at PS exit [  10 11 ppb] 1.521.3 (2*)

6. H. Haseroth July 26 – August 1, 2004 NuFact04, Osaka 6 Linac4 parameters Relaxed parameters Space and infrastructure available in the PS South Hall RF from LEP (klystrons, waveguides, etc. - already in stock) Linac4 could be later used as front-end of the SPL: its RF structures are designed to operate at the full SPL duty cycle.

7. H. Haseroth July 26 – August 1, 2004 NuFact04, Osaka 7 DTLCCDTLSCL 3MeV40MeV90MeV160MeV Drift Tube Linac 352 MHz 16.7 m 3 tanks 5 klystrons Side Coupled Linac 704 MHz 28.1 m 20 tanks 5 klystrons Cell-Coupled Drift Tube L. 352 MHz 30.1 m 33 tanks 6 klystrons Total Linac4: 86.5 m, 17 klystrons 30 mA, 0.1% duty MEBTRFQH- 95keV chopping line 3.6 m IPHI RFQ 6 m 1 klystron Final Energy 160 MeV, factor 2 in  2 w.r.t. present 50 MeV Linac2 Linac4 layout

8. H. Haseroth July 26 – August 1, 2004 NuFact04, Osaka 8 Installation Layout 3 MeV Test Place

9. H. Haseroth July 26 – August 1, 2004 NuFact04, Osaka 9 The 3 MeV Test Stand H - ECR ion source HV pulsed power supplies for the LEP klystrons Specific Components Chopper structure Bunching cavities Beam Shape and Halo Monitor IPHI RFQ

10. H. Haseroth July 26 – August 1, 2004 NuFact04, Osaka 10 The 3 MeV Test Stand Beam dynamics at low energy. Development of the Chopper line: –to generate the required time structure of the beam –to clean the beam from halo –to match it to the subsequent RF structures.

11. H. Haseroth July 26 – August 1, 2004 NuFact04, Osaka 11 The H - ECR Source Tests on the prototype source are under way. Design work will be carried out during the rest of 2004 and 2005. The final source is not expected before 2007.

12. H. Haseroth July 26 – August 1, 2004 NuFact04, Osaka 12 The RFQ The IPHI (“Injecteur de Protons de Haute Intensité”) RFQ is at the core of the 3 MeV Test Place. It is being developed in France within the IPHI collaboration between CEA and CNRS which CERN has recently joined. RF power is generated by a LEP klystron (352.21 MHz, 1 MW CW) that will be operated in pulsed mode, by means of dedicated power supplies expressly developed by a collaboration between GSI and CERN.

13. H. Haseroth July 26 – August 1, 2004 NuFact04, Osaka 13 HV Pulsed Power Supplies for the LEP klystron CERN and GSI are formalizing an agreement for the development of the power supplies based on common requirements (Linac4 @ CERN and FAIR injector @ GSI). First power supply to be delivered before end 2005, second before end 2006.

14. H. Haseroth July 26 – August 1, 2004 NuFact04, Osaka 14 The Chopper line General guidelines Compact design3 m length Dynamic range20 – 60 mA Small  growth  z = const  r out = 1.17  r in Tolerant to alignment errors Good vacuum~10 -8 Torr

15. H. Haseroth July 26 – August 1, 2004 NuFact04, Osaka 15 Beam Dynamics in the Chopper Line The chopper line is designed transversely as five FODO periods, while longitudinally three RF cavities match the beam from the RFQ output to the (future) DTL input. Buncher cavity Buncher cavity Buncher cavity Chopper structure Chopper structure RFQ output DTL input

16. H. Haseroth July 26 – August 1, 2004 NuFact04, Osaka 16 Beam Chopping (1) A beam dump has been designed to intercept the deviated beam 1 m downstream from the last chopper structure (radial separation between the beam centers: 1.5 cm) 3 bunches are dumped 5 bunches are transmitted Beam Dump – Side view  = 10 degrees Un-chopped beam ~ 100 mm Water  Vacuum flange

17. H. Haseroth July 26 – August 1, 2004 NuFact04, Osaka 17 Beam Chopping (2) 2 ns rise/fall time is required for bunch selectivity (352 MHz beam structure), ±500V between the deflecting plates to get the required separation at the dump. Double meander structure on Alumina substrate The first chopper structure is under fabrication The prototype of the RF amplifier is under test Pulse length: 8ns to 2  s Rep. rate (max): 45 MHz

18. H. Haseroth July 26 – August 1, 2004 NuFact04, Osaka 18 Longitudinal matching The longitudinal matching is performed by 3 RF cavities working at 352 MHz: two with 30 mm aperture (B30), and one with 40 mm aperture (B40) placed in the chopping region. B30B40 Frequency (MHz)352.0352.0 Gap length (mm)14.014.0 Q value2500024000 Shunt impedance (M  )1.280.64 R/Q52.227.1 Nominal voltage (kV)140100 Dissipated power (kW peak)1616.2 Kilpatrick factor1.221.16 The electromagnetic and mechanical design has been completed for the whole set of RF cavities. The construction phase for the first B30 cavity is starting and will be completed within the end of 2004.

19. H. Haseroth July 26 – August 1, 2004 NuFact04, Osaka 19 The Beam Shape & Halo Monitor Longitudinal measurement Measure residual H - in (not completely) chopped buckets with a sensitivity of ~ 1000 ions, in the vicinity of full bunches (10 8 ions). Detector must be turned ON/OFF within 1 ns, gating ratio 1:10 6 Transverse measurement Halo diagnostics: Beam core: d=1 cm, 10 8 H - /bunch/ cm 2 Beam halo: d=4 cm, 10 3 H - /bunch/ cm 2 Active area of detector 4 × 4 cm Dynamic range: 1:10 6 by integrating over several buckets All components have been delivered. The vacuum chamber is being designed. The detector will be commissioned during the first months of 2005.

20. H. Haseroth July 26 – August 1, 2004 NuFact04, Osaka 20 Measurement Program The 3 MeV test place will be used to commission the different components of the line and perform “conventional” measurements on the beam, in order to scan the full dynamic range of the system. Three sets of measurements have particular relevance: Validation of the Chopper principle and hardware Characterize the separation capability (on/off) of the chopper line (chopper voltage) and its time selectivity (rise and fall time). Beam matching properties of the line Measure longitudinal and transverse emittance (expected accuracy within 10%) within different beam conditions. Halo studies Optimize the collimation system by characterizing the beam halo in shape and intensity.

21. H. Haseroth July 26 – August 1, 2004 NuFact04, Osaka 21 Planning of the Project Linac4 approval Decision on SPL Test of Linac4 RF structures is possible

22. H. Haseroth July 26 – August 1, 2004 NuFact04, Osaka 22 Status of the Project The European Union is supporting beam dynamics studies and RF system developments in the frame of the HIPPI “Joint Research Activity”. The design of the 3 MeV Test Stand is almost completed. Still missing: –study of the beam current monitor –design of the vacuum chamber (short sections between major components) The design of the major components will be completed in 2004. The start of Linac4 construction in 2006 has been included by the CERN DG among the strategic priorities of the laboratory  The 3 MeV Test Stand is being designed to become the Linac4 Front End.

23. H. Haseroth July 26 – August 1, 2004 NuFact04, Osaka 23 The full picture … Linac4 approval SPL approval LHC upgrade RF test place ready 3 MeV test place ready CDR 2

24. H. Haseroth July 26 – August 1, 2004 NuFact04, Osaka 24 Thank you and Carlo Rossi for the preparation of this presentation