1. LARP Collaboration Meeting, April 19, 2007Super-Ferric Fast Cycling SPS – Henryk Piekarz1 LHC Accelerator Research Program bnl-fnal-lbnl-slac - Motivation - Magnet choice for the SF-SPS - The SF-SPS accelerator arrangement - Summary Super-Ferric Injector in the SPS Tunnel

2. LARP Collaboration Meeting, April 19, 2007Super-Ferric Fast Cycling SPS – Henryk Piekarz2 Motivation Replace current SPS accelerator with a machine that will enable to: (1) Inject/stack two proton beams in the LHC (or in the LER, a possible pre-injector for the DLHC) (2) Cycle two proton beams at 0.5 Hz (2 sec cycle) for the neutrino physics and other FT experiments Current CERN accelerator complex LER injector in LHC tunnel

3. LARP Collaboration Meeting, April 19, 2007Super-Ferric Fast Cycling SPS – Henryk Piekarz3 New SPS Magnet Considerations As an injector to the LHC the SPS magnets must have a very high quality B-field to preserve good beam emittance at injection to LHC, necessary e.g. to minimize beam losses and facilitate good LHC performance. The magnetic field in the gap is affected by both the conductor and the core. Maintaining a high quality B-field in the magnet gap during a fast ramping or cycling operation is a very difficult task due to significant AC power losses caused by eddy currents and magnetization with conductor embedded in the magnetic flux. For the conductor dominated magnetic design, however, the required current in the coil is minimized by using multiple windings. Therefore, most of the fast cycling magnets use this option, but significant difficulties are encountered in the operation of such magnets due to AC losses. To minimize the effect of the AC losses we propose to consider for the new SPS a CORE dominated magnetic design in a super-ferric regime, hence SF-SPS.

4. LARP Collaboration Meeting, April 19, 2007Super-Ferric Fast Cycling SPS – Henryk Piekarz4 SF-SPS Magnet Consideration, part 2 We propose a “frame” type core due to: - high-quality B-field in the magnet gap - minimized conductor effect on the B-field in the gap - minimized physical size, and thus the magnet cost This magnetic design is for a 2 Tesla field in a 40 mm gap, with a single conductor winding of 87 kA current, and a laminated (1mm) Fe3%Si core. Very little of magnetic flux crosses conductor.

5. LARP Collaboration Meeting, April 19, 2007Super-Ferric Fast Cycling SPS – Henryk Piekarz5 Conductor Considerations Observation: - For the current of ~100 kA a superconductor cable must be used - About 300 strands of NbTi, or HTS can carry 100 kA current at 5 K Here are some possible SF-SPS conductor arrangements:

6. LARP Collaboration Meeting, April 19, 2007Super-Ferric Fast Cycling SPS – Henryk Piekarz6 Crudely Estimated Conductor AC Losses Cable type dB/dT [T/s] B max [T] Power loss [W/m] 2 T cycle time [s] 4 T cycle time [s] 2 T cycle power loss per ring [kW] 4 T cycle power loss per ring [kW] NbTi single winding 2 2 1 2 n.a. 7 HTS- 344S single winding 2 2 0.1 2 n.a. 0.7 n.a. NbTi (GSI) multiple winding 1 4 3 4 8 21 The NbTi and HTS-344S single cable power losses are estimated. The NbTi multiple winding of GSI cable losses are measured. The required cooling power for the SPS single ring based on the GSI-type magnets is equal in size to the one LHC cryo-plant.

7. LARP Collaboration Meeting, April 19, 2007Super-Ferric Fast Cycling SPS – Henryk Piekarz7 Possible Cycling Times with SF-SPS As a result of low cooling power demand in SF-SPS magnet we assume two rings (DSF-SPS) will accelerate interchangeably beams from PS2 leading to the following cycling times: (1) Collider operation; T cycle ~ 14 sec / beam including ~10 sec stacking time (current SPS super-cycle / beam ~ 22 sec) (2) Fixed Target operations; T cycle ~ 2 sec (current minimum cycle / beam ~ 8 sec)

8. LARP Collaboration Meeting, April 19, 2007Super-Ferric Fast Cycling SPS – Henryk Piekarz8 Proposed DSF-SPS Accelerator Arrangement DSF-SPS arrangement: -Single transmission-line conductor, PS and CL per ring -Both rings will share interchangeably a common RF power

9. LARP Collaboration Meeting, April 19, 2007Super-Ferric Fast Cycling SPS – Henryk Piekarz9 DSF-SPS Power Supply and Current Leads DSF-SPS Power supply design (S. Hays) will be based on the MI power supply, with exception that it will be twice the MI PS power. The current leads (Y. Huang) will use the HTS cable with increasing number of strands as the cold end of the copper leads is approached.

10. LARP Collaboration Meeting, April 19, 2007Super-Ferric Fast Cycling SPS – Henryk Piekarz10 DSF-SPS Magnets Magnet list is based on a preliminary lattice design by J. Johnstone. The arc magnets are combined function dipoles. Cell length = 63.99 m Phase / cell = 92.5 0, β max = 96.4 m, η max = 3.81 m Cell typeMagnet typeL magnet [m] B [T] B’ [T/m] Number Arc sections GF/GD QF QTF 7.165 0.660 0.339 1.9 +/- 4.7 +/- 70.00 744 6 Straight sections QF/QD 0.660 +/- 70.00 48 Total 804

11. LARP Collaboration Meeting, April 19, 2007Super-Ferric Fast Cycling SPS – Henryk Piekarz11 DSF-SPS Cost Estimate This crude cost estimate is based on the cost studies for the VLHC with an updated material cost to the 2006 $. DSF-SPS subsystem [$M] Arc magnets*) 200 Correctors 10 RF system 40 Beam pipe vacuum system 20 Cryogenic plant 20 Magnet R&D 5 Prototyping 5 Total 300

12. LARP Collaboration Meeting, April 19, 2007Super-Ferric Fast Cycling SPS – Henryk Piekarz12 Summary - The DSF-SPS accelerator will provide high quality beams for the injection to the LHC shortening the LHC cycle in the same time and - It will allow for a 4-fold increase of target power for the neutrino experiments.