1. EDM2001 Workshop May 14-15, 2001 AGS Intensity Upgrade (J.M. Brennan, I. Marneris, T. Roser, A.G. Ruggiero, D. Trbojevic, N. Tsoupas, S.Y. Zhang) Proton driver parameters and layout Beam loss considerations 1.2 GeV Superconducting Linac 2.5 Hz AGS power supply and rf system 4 MW Upgrade Bunch compressor ring Cost estimate

2. AGS proton driver parameters 1 MW AGSAGS presently Total beam power [MW]1 0.14 Beam energy [GeV]2424 Average current [  A]426 Cycle time [ms]4002000 No. of protons per fill1  10 14 (0.6 - 0.7)  10 14 Average circulating current [A]5.94.2 No. of bunches per fill66 No. of protons per bunch1.7  10 13 ~ 1  10 13 Time between extracted bunches [ms]20 33 Rms bunch length [ns]330 Peak bunch current [A]40030 Total bunch area [eVs]5 15 Rms bunch emittance [eVs]0.30.8 Rms momentum spread0.0050.001

3. AGS proton driver layout AGS 1.2 GeV  24 GeV 0.4 s cycle time (2.5 Hz) 116 MeV Drift Tube Linac (first sections of 200 MeV Linac) BOOSTER High Intensity Source plus RFQ Superconducting Linacs To RHIC 400 MeV 800 MeV 1.2 GeV 0.15 s0.1 s0.15 s To Target Station

4. Beam loss at H - injection energy AGS Booster PSRSNS1 MW AGS Beam power, Linac exit, kW3 80100050 Kinetic Energy, MeV200 80010001200 Number of Protons N P, 10 12 15 31100100 Vertical Acceptance A,   m89 14048055  2  3 0.57 4.506.759.56 N P /  2  3 A), 10 12   m0.296 0.0490.0310.190 Total Beam Losses, %5 0.30.13 Total Loss Power, W150 24010001440 Circumference, m202 90248807 Loss Power per Meter, W/m0.8 2.74.01.8

5. Beam losses in AGS Major loss points Present AGS 1 MW AGS % particlesBeam power% particlesBeam power Injection and early accel.: Controlled3.0 %1.5 kW Uncontrolled30 %1.9 kW0.3 %0.2 kW Transition 2.0 %0.4 kW1.0 %2.9 kW Total:2.3 kW4.6 kW l Injection modeled after SNS but much lower repetition rate and less foil traversals  Allow 30 times more beam loss l Transition losses are presently dominated by beam momentum spread required for AGS injection stacking. Direct injection should eliminate chromatic transition losses. l 4.6 kW should be acceptable for hand maintenance.

6. AGS injection simulation Injection parameters: Injection turns360 Repetition rate2.5 Hz Pulse length1.08 ms Chopping rate0.65 Linac ave./peak current20 / 30 mA Momentum spread  0.15 % Inj. beam emittance (95%)  m RF voltage450 kV Bunch length85 ns Longitudinal emittance1.2 eVs Momentum spread  0.48 % Circ. beam emit. (95%) 100  m

7. 1.2 GeV Superconducting Linac Beam energy 0.116  0.4 GeV0.4  0.8 GeV0.8  1.2 GeV Rf frequency805 MHz1610 MHz1610 MHz Accelerating gradient11.9 MeV/m22.0 MeV/m21.5 MeV/m Length75.4 m43.9 m42.6 m Beam power, exit17 kW34 kW50 kW

8. New AGS main magnet power supply presently: l Repetition rate2.5 Hz1 Hz l Peak power110 MW 50 MW l Average power4 MW 4 MW l Peak current4.3 kA 5 kA l Peak total voltage  25 kV  10 kV l Number of power converters / feeds62

9. Distribution of current feeds

10. AGS rf system upgrade Use present cavities with upgraded power supplies (two 300 kW tetrodes/cavity) presently: Rf voltage/turn1 MV0.4 MV harmonic number246 - 12 Rf frequency~ 9 MHz3 - 4.5 MHz Rf peak power3 MW Rf magnetic field18 mT

11. Bunch merging and compression 80 ns h = 24 1.2 eVs/bunch Adiabatic merging: h = 6 100 kV/turn ~ 5 eVs/bunch h = 24 1 MV/turn Adiabatic quad pumping: 15 ns (3 ns rms)

12. Towards 4 MW Upgrade IUpgrade IIUpgrade III Linac intensity/pulse1.2  10 14 2.4  10 14 2.4  10 14 Linac rep. rate2.5 Hz2.5 Hz5.0 Hz Linac extraction energy1.2 GeV1.5 GeV1.5 GeV  2  3 9.614.914.9 Beam power54 kW144 kW288 kW AGS intensity/pulse1.0  10 14 2.0  10 14 2.0  10 14 AGS rep. rate2.5 Hz2.5 Hz5.0 Hz* Rf peak power3 MW6 MW8 MW Rf gap volts/turn1 MV1 MV1.5 MV AGS extraction energy 24 GeV24 GeV24 GeV Beam power1 MW2 MW4 MW Bunch area5 eVs10 eVs10 eVs Compressor ringnoyesyes *Symmetric cycle (0.1 s up, 0.1 s down) without flattop.

13. 4 MW AGS proton driver layout AGS 1.2 GeV  24 GeV 0.2 s cycle time (5 Hz) 116 MeV Drift Tube Linac (first sections of 200 MeV Linac) BOOSTER High Intensity Source plus RFQ Superconducting Linacs To RHIC 400 MeV 800 MeV 1.5 GeV 0.1 s To Target Station 24 GeV Superconducting Compressor Ring 24 GeV Superconducting Storage Ring

14. Compressor ring Small superconducting ring to compress a single 24 GeV, 10 eVs bunch to 3 ns rms length. Small size reduces space charge tune shift and gap volt requirements. l Circumference200 m l Energy24 GeV l Dipole field~ 4 Tesla l Packing factor60 % Transition gamma~ 40 (d   /d  < 4) l Momentum acceptance  5 % (FFAG type lattice?) l Rf frequency 6 MHz (h = 4) l Rf Voltage per turn200 kV l Bunch length compression (rms)20 ns  3 ns

15. Bunch compression

16. Cost estimate