1. MeRHIC Internal Cost Review October, 7 2009 Dmitry Kayran for injector group MeRHIC Internal Cost Review October 7-8, 2009 MeRHIC: Injection System Gun - 10 MeV Injector – 100 MeV Pre-accelerator

2. MeRHIC Internal Cost Review October, 7 2009 (April 09) Linac 1 Linac 2 Main ERLs; 6 cryomodules x 6 cavities x 18 Mev/cav = 0.65 GeV per linac 0.75, 2.05, 3.35 GeV 4 GeV 0.1, 1.4, 2.7 GeV Pre-accelerator 90 MeV ERL Electron gun 0.1 GeV IR2 region features: - asymmetric detector hall (appropriate for asymmetric detector for e-p collisions) - long wide (7.3m) tunnel on one side from the IR (enough space to place energy recovery linac(s)) Main components: -100 MeV injector on the basis of polarized electron gun (50 mA) and pre-accelerator ERL. -Two main ERLs (one of them in the RHIC tunnel) with maximum 0.65 GeV energy gain per linac. -Recirculation passes are going outside of the existing tunnel: warm magnets, acceptable synchrotron radiation power. 10 MeV Injector 90 MeV Linac 1 cryomodule 5 cavities+3 rd harmonics 100 MeV 11 m 10 MeV x 50 mA 0.5 MW Beam Dump Merger to MeRHIC Merger from eRHIC Merger to eRHIC 100MeV pre-accelerator MeRHIC: General layout

3. MeRHIC Internal Cost Review October, 7 2009 100 MeV Pre Accelerator ERL 3 Injector Parameters Polarized Gun (200kV) Cathode GaAs, Laser 780nm Emax= 10 MeV Iavr =50 mA, Q per bunch =5nC Pre-accelerator ERL: One pass Energy gain 90 MeV Einj & Eextr=10 MeV Emax =100 MeV eBeam parameters : E=100 MeV Iavr=50 mA Ipeak=500 A Reprate = 9.8 MHz Emittance =70 mm-mrad Banchlength = 3 mm dE/E = 1E-3 Gatling Gun (Ek=200keV) 10 MeV Injector 90 MeV Linac 1.4, 2.7, 4 GeV 11 m 10 MeV x 50 mA 0.5 MW Beam Dump from MeRHIC arcs to MeRHIC vertical combiner 10 MeV Booster Linac 30 m

4. MeRHIC Internal Cost Review October, 7 2009 Gatling Gun *) ParameterValue Laser longitudinal distribution Gaussian Bunch length at cathode0.5nS [FWHM] Laser transverse distribution Uniform Laser spot diameter8mm Bunch charge5nC Accelerating voltage200kV Cathode-anode gap3cm Integrated solenoid field2.1kG-cm Dogleg funneling system is spin transparent Electrostatic kicker Rotating field kicker ~ 50 mA from injector is needed. State of the art electron polarized source is 1 mA. The multi cathode to reduce load on a single cathode can be used *) the Gatling gun is the first successful machine gun, invented by Dr. Richard Jordan Gatling. Electrostatic kicker

5. MeRHIC Internal Cost Review October, 7 2009 Laser No Commercial Laser to meet the need! LDRD for laser development 2W/mA (780 nm, 0.1% QE) Three possible approaches: –Fiber oscillator  Fiber amplifier  2ћω to 780 nm –Ti:S Oscillator  Ti:S amplifier 780 nm –Diode oscillator  Power amplifier 780 nm All three approaches will be evaluated Best selected, built & test to drive up to 2 mA Expected Results Laser to drive one cathode of the multi cathode gun Laser system scalable to deliver full EIC electron beam 2 LDRD’s for the new injector and laser have been approved

6. MeRHIC Internal Cost Review October, 7 2009 Beam pipe radius: 5cm DC Gun voltage 200 kV, GaAs cathode, with funneling system (1.5 m). Spin rotator ( Wien filter: B=36Gs, E=751 kV/m, 1m, spin rotation 90 degrees). Bunching cavity is a low frequency (112MHz) cavity with outer radius of about 105cm 3 rd harmonic frequency (336MHz) cavity with outer radius of about 35cm Booster linac (6x112MHz cavity ) boosts the beam energy to 10MeV (4.5 m). Solenoid Gun 200 KeV Spin rotator Solenoid Bunching Cavity 3 rd harmonic cavity Solenoid 11 m 10MeV Injector layout 10 MeV booster linac EB

7. MeRHIC Internal Cost Review October, 7 2009 Beam dynamics in 10 MeV injector result of PARMELA simulations Emittances evolutionBunch length evolution Ballistic bunching works well Transverse emittances are within the required limit (can be improved further more). Bunch length also matches the requirement. Beam parameters at 10 MeV Charge per bunch 5 nC Emittance-X: 60 mm-mrad Emittance-Y: 54 mm-mrad Final bunch length: 2.8mm Energy spread: 1%

8. MeRHIC Internal Cost Review October, 7 2009 MeRHIC Pre-accelerator: 90 MeV Linac Pre-accelerator linac: Standard MeRHIC linac cryomodule (~10m) with 5x703 MHz 5-cell cavities and one 3rd harmonic 2.11 GHz inside. Two transition sections (0.5 m each) attached from both ends Energy gain 90 MeV 10 MeV 100 MeV Standard main MeRHIC linac cryomodule Transition section 703.75 MHz2.11 GHz

9. MeRHIC Internal Cost Review October, 7 2009 1.4, 2.7 GeV and 4 GeV beam lines are separated vertically can be tuned separately. 30 m Low/High Energy Switch yards 11 m 10 MeV 10 MeV, 100MeV100 MeV, 10MeV 100MeV 2 Dog-Legs (at 10MeV): 2 x30°dipoles,B=560 Gauss L=30 cm 6 quadrupoles 2 Dog-Legs(at 100MeV): 2 x30° dipoles, B=5.6 kGauss, L= 30 cm 6 quadrupoles Beam Dump Injector

10. MeRHIC Internal Cost Review October, 7 2009 Summary 100 MeV Pre Accelerator elements: 10 MeV Injector (special): –Polarized Gun/Cathode/Laser (approved LDRDs) –Spin rotator & power supply –Booster, Bunching, 3 rd harmonics 90 MeV linac will use: –One MeRHIC standard 10m cryo- module –With 5 standard MeRHIC cavities + 3 rd hormonic Doglegs and matching sections – Magnets & Power supplies (dipoles, solenoids, quadrupoles, correctors) Vacuum system eBeam and laser beam Instrumentation Beam dump Based on simulations: 10 MeV Injector will provide e-beam with required parameters both longitudinal and transverse More beam dynamics of 100 MeV pre accelerators needs to be done