Preliminary design of proton and ion linacs for

Preliminary design of proton and ion linacs for SPPC Injector Y. R. Lu, H. P. Li, X. W. Zhu, Q. Fu, J. Liu, K. Zhu, Z. Wang State Key Lab of Nuclear Physics and Technology, Peking University

Contents A. General requirements B. Brief introductions of injector systems for proton and ion accelerators C. Preliminary design of proton and ion linacs. D. Conclusions CEPC-SPPC Beihang University

Injector chain (J. Y. Tang 1/3) (for proton beam) p-Linac: proton superconducting linac p-RCS: proton rapid cycling synchrotron MSS: Medium-Stage Synchrotron SS: Super Synchrotron CEPC-SPPC Beihang University

Some key features(J. Y. Tang 2/3) • p-linac: – Superconducting linac, H- beam, pulsed mode, similar to the SNS linac, – Almost mature technology – Beam energy may be increased from 1. 2 Ge. V to 1. 5 -2. 0 Ge. V (ref. SPL, ESS) • p-RCS • • Rapid cycling synchrotron, high power (1. 7 MW), first in this energy range Painting injection by stripping, fast extraction Technically challenging, beam loss control, Reference: a scheme for the proton driver for Neutron Factory; J-PARC/RCS • MSS – Bunch structure formation by longitudinal splitting (RF barrier for gap? ) – Reference: CERN/SPS, FNAL/MI (but higher beam power, 1. 2 MW) • SS – Te. V with high repetition, high energy in beam, SC magnets (ref: LHC, Tevatron) [B: 8 T; RF: 200 MHz] – Slow extraction may be needed (test beam and other physics programs) • There are different schemes in RF acceleration and bunch formation along with the injector complex. CEPC-SPPC Beihang University

Major parameters for the injector chain(J. Y. Tang 3/3) Value p-Linac Energy Average current Length RF frequency Repetition rate Beam power p-RCS Energy Average current Circumference RF frequency Repetition rate Beam power Unit 1. 2 Ge. V MSS Energy 0. 7 m. A Average current ~300 325/650 50 0. 84 m MHz Hz MW 10 Ge. V Circumference RF frequency Repetition rate Beam power SS Energy 0. 19 m. A Accum. protons 900 36 -40 25 1. 7 m Circumference MHz RF frequency Hz Repetition period MW Beihang Protons per bunch CEPC-SPPC University Dipole field Value Unit 180 Ge. V 21 u. A 3600 40 0. 5 1. 2 m MHz Hz MW 2. 1 Te. V 5. 3 E 14 7200 30 2. 0 E 11 8 m MHz s T

CERN Accelerator Complex LHC Injector • Lianc 2 (p, 50 Me. V, 1978) • PSB (1. 4 Ge. V, 1972) • PS (28 Ge. V, 1959) • SPS (450 Ge. V, 1976) CEPC-SPPC Beihang University

Implementation of The New Injectors: Stage 1 – Linac 4 (2/2) • Block Diagram Linac 4 45 ke. V Linac 4: 80 m, 18 klystrons 3 Me. V H- RFQ CHOPPER RF volume source (DESY) 45 k. V Extrac. Radio Frequency Quadrupole 3 m 1 Klystron 550 k. W Chopper & Bunchers 3. 6 m 11 EMquad 3 cavities Ion current: 40 m. A (avg. ), 65 m. A (peak) DTL Drift Tube Linac 18. 7 m 3 tanks 3 klystrons 4. 7 MW 111 PMQs 50 Me. V CCDTL Cell-Coupled Drift Tube Linac 25 m 21 tanks 7 klystrons 7 MW 21 EMQuads 94 Me. V 160 Me. V PIMS Pi-Mode Structure 22 m 12 tanks 8 klystrons ~12 MW 12 EMQuads RF accelerating structures: 4 types (RFQ, DTL, CCDTL, PIMS) Frequency: 352. 2 MHz Duty cycle: 0. 1% phase 1 (Linac 4), 3 -4% phase 2 (SPL), (design: 10%) CEPC-SPPC Beihang University

Injector Complex Upgrade – Proton Operation Proton flux / Beam power 50 Me. V Linac 2 160 Me. V Output energy 1. 4 Ge. V 26 Ge. V 50 Ge. V 450 Ge. V 1 Te. V 7 Te. V ~ 14 Te. V PS B Linac 4 LP-SPL PS SPS LHC / s. LHC PS 2 Linac 4: H- Linac (160 Me. V) LP-SPL: Low Power- Superconducting Proton Linac (4 Ge. V) PS 2: High Energy PS (4 to 50 Ge. V – 0. 3 Hz) SPS+: Superconducting SPS (50 to 1000 Ge. V) s. LHC: ‘Superluminosity’ LHC or High Luminosity LHC (up to 1035 cm-2 s-1 peak) DLHC: ‘Double energy’` LHC (1 to ~14 Te. V) SPS+ Stage 1: Linac 4 - construction 2008 – 2014 DLHC Stage 2: PS 2 and LP-SPL: preparation of Conceptual Design Reports for - project approval mid 2012 - start of construction begin 2013 CEPC-SPPC Beihang University

Implementation of The New Injectors: Stage 2 – LP-SPL to PS 2 • Block Diagram 110 m 0. 73 Ge. V 9 x 6 b=0. 65 cavities 427 m 4 Ge. V High b cryomodules Ejectio n Medium b cryomodul e 186 m 1. 4 Ge. V High b cryomodules 5 x 8 b=1 cavities 14 x 8 b=1 cavities CEPC-SPPC Beihang University Debuncher s To PS 2 0 m 0. 16 Ge. V TT 6 to ISOLDE From Linac 4 SC-linac (160 Me. V 4 Ge. V) with ejection at intermediate energy Length: ~430 m

Previous RHIC Accelerator Complex 840 m & Its Heavy Ion. Tandem-to-Booster: Injector EBIS-to-Booster : 30 m 100 Ge. V/u 10 Ge. V/u Tandem CEPC-SPPC Beihang University

Major parameters for RHIC CEPC-SPPC Beihang University

Upgrade Scenario for RHIC Heavy Ion Pre-Injector • The Tandem: - Tandem to Booster transport line is 860 m long. 44 Quadrupoles 6 Large Dipoles 20 Faraday Cups 71 Steering Dipoles 25 Multiwires Dozens each of Pumps. . . ü After upgrade, transport from the EBIS to the Booster will be only 30 m long. CEPC-SPPC Beihang University

The Proposed Linac-Based RHIC Pre-Injector - RFQ: 17 – 300 Ke. V/u; 100 MHz - Linac: 0. 3 – 2. 0 Me. V/u; 100 MHz CEPC-SPPC Beihang University

RFQ Beam Dynamics Design Parameters CEPC-SPPC Beihang University

Main Parameters of IH-DTL Required for RHIC Injection CEPC-SPPC Beihang University

Considerations for The Heavy Ion Pre. Injector • 频率的选择: • 出口能量 300 Ke. V/u CEPC-SPPC Beihang University

FAIR China, Finland, France, Greece, Great Britain, India, Italy, Austria, Poland, Romania, Russia, Sweden, Slovakia, Slovenia and Spain. CEPC-SPPC Beihang University

FAIR Beam Energy [Ge. V/u] 2. 7 for U 28+ to 29 for protons; Bunch compression to 60 ns of 5 1011 U ions, fast and slow extraction; 5 10 -12 mbar operating vacuum GSI Beam Energy 70 Me. V; max. Current 70 m. A; 7· 1012 Protons per pulse; Beam pulse length ≤ 40 µs; Rep. rate ≤ 4 Hz; Operating frequency 325, 224 MHz; Accelerator length 30 m SIS 100 circumference 1100 m SIS 18 p-linac SIS 300 UNILAC SIS 100 p-linac Beam Energy [Ge. V/u] 34 for U 92+; Pulsed super conducting cos -magnets; slow extraction of 3 1011 U-ions per sec. with high duty cycle SIS 300 Unila c HESR circumference 574 m Antiproton Prod. Target HESR Super - FRS circumference 206 m RESR CR FAIR p-bar target RESR NESR circumference 220 m CR CEPC-SPPC Beihang University

GSI Accelerators The Linear Accelerator UNILAC (UNIversal Linear ACcelerator), Length 120 meter, Ions up to 20 % of velocity of light (60. 000 km/s) IH-type RFQ accelerates the ion beam from 2. 2 ke. V/u to 120 ke. V/u Alvarez DTL output energy 11. 4 Me. V/u up to U 28+ RFQ 2. 5 ke. V/u to 300 ke. V/u IH to 1. 4 Me. V/u. UNILAC Experimental hall Ion sources IH-DTL accelerates up to the final energy of 1. 4 Me. V/u. 10 single-gap-cavities are separately RF powered and controlled. Energy gain is up to 250 ke. V/u each. UNILAC layout CEPC-SPPC Beihang University

GSI Accelerators Excellent performance for more than 30 Years, meanwhile problems with cavity cooling and vacuum High current injector [HSI]: RFQ and IH structures by Ulrich Ratzinger RFQ renewed by Stepan Yaramyshev CEPC-SPPC Beihang University

GSI Accelerators UNILAC RF performance Operating Frequencies 36, 108, 216 MHz RF Power up to 2 MW (1, 6 MW) pulsed (5 ms @ 50 Hz) Accelerator Cavities RFQ, IH-Structures, Alvarez-Type-Structures, Single-Gap-Structures as well as Quarter wave and Spiral-Resonators Tube types RS 2024, RS 1084 and RS 2074 all Siemens types by Thales Number of sockets 24 x RS 2024 29 x RS 1084 8 x RS 2074 Solid State Amps various types used as drivers and RF supply for Bunchers from 2 to 8 k. W CEPC-SPPC Beihang University

GSI Accelerators UNILAC future FAIR Injector HE LINAC short pulse machine 15 m. A U 28+ 11, 4 Me. V/u 100 μs beam pulse ~1% duty factor replacement of the Alvarez structures by IH renewing of RF amplifiers 2 MW power tube not obsolete for the next 20 years solid state drivers digital LLRF CEPC-SPPC Beihang University

FAIR Accelerators Proton Linac CCH section picture taken on 30 th of March 2012 CEPC-SPPC Beihang University

FAIR Accelerators Proton Linac CCH section • ECR proton source & LEBT • RFQ • 1 Klystron (~1. 5 MW) • 3 re-bunchers • 3 Solid State Amplifier (~45 k. W) • 6 * 2 accelerating cavities (CCH-DTL) • 6 Klystrons (2. 5 MW) • 2 dipoles, 45 quadrupoles, 7 steerers • 10 turbo pumps, 34 ion pumps, 9 sector valves • 41 beam diagnostic devices = 10 RF systems in total Klystron 325. 224 MHz 2. 8 MW @ 1‰ duty factor CEPC-SPPC Beihang University

Accelerator Driven Systems ADS The European MYRRHA Project IAP Team for the MAX Project: Horst Klein, Dominik Mäder, Holger Podlech, Ulrich Ratzinger, Alwin Schempp, Rudolf Tiede, Markus Vossberg, Chuan Zhang

Preliminary Design of Proton Linac (50 Me. V , 40 m. A） CEPC-SPPC Beihang University

Schematic layout Diagnost ics Buncher Q D QT 1 QT 2 QT 3 QT 4 QT 5 QT 6 QT 7 QT 8 +MEB T RFQ DTL 2 DTL 1 DTL 3 19. 09 m 0. 05 M e. V 3. 0 Me V 20. 4 M e. V 34. 1 M e. V CEPC-SPPC Beihang University 50. 65 Me. V

Main parameters of proton RFQ Parameters Value Frequency(MHz) 325 Input/output energy(Me. V) 0. 05/3. 02 Beam Current(m. A) 40 Transmission(%) 98. 467 Vane voltage(k. V) 85 Cell numbers 358 Kilpatrick Factor 1. 79 Vane Length(cm) 361. 32 Synchronous Phase(deg) -90/-25 Maximum Modulation 2. 308 Minimum Aperture(cm) 0. 207 CEPC-SPPC Beihang University

CEPC-SPPC Beihang University

CEPC-SPPC Beihang University

CEPC-SPPC Beihang University

Parameters CEPC-SPPC Beihang University

DTL parameters: Parameters DTL 1 DTL 2 DTL 3 325 325 3. 02/20. 44/34. 10/50. 65 Length(cm) ~435 ~403 ~495 Gap number 58 35 36 Transmission(%) 99. 98 99. 99 Acceleration gradient(MV/m) 4. 00 3. 39 3. 34 Max field(MV/m) 13. 09 17. 78 17. 20 Kilpatric Factor (17. 86 MV/m) 0. 73 0. 996 0. 963 Frequency(MHz) Input/output energy(Me. V) CEPC-SPPC Beihang University

Room Temperature Low and Medium Energy Cavities IAP Frankfurt CERN IAP GSI FNAL REX-ISOLDE

Linac beam dynamics Standard concept: negative synchronous particle st < 90° Strong focusing concept in periodic lattice fs = -30°

Linac beam dynamics (U. Ratzinger in IAP) Alternative concept for efficient bl/2 H-type structures: Combined 0 deg Structure KONUS （LORASR） Phase shift at transition: rebunching → 0° section One structure period consists of a quadrupole triplet, a rebunching section and a main acceleration section.

Room temperature cavity development copper plated steel r. t. IH-DTL W < 30 Me. V 30 -250 MHz r. t. CH-DTL W < 150 Me. V 150 -700 MHz bulk niobium s. c. CH-DTL W < 150 Me. V 150 -700 MHz

Beam envelope 99. 4% 95% CEPC-SPPC Beihang University

CEPC-SPPC Beihang University

Quadrupole lens parameters: Diameter=20 mm Quadrupole QD QT 1 QT 2 QT 3 QT 4 Eff. Space (mm) 20 20/20 Eff. Pole length (mm) 48/48 36/66/36 37/68/37 39/70/39 38/71/38 Field gradient (T/m) 79/77 82/79. 5/82 82/81. 5/8 80/83/80 2 80/81/80 Quadrupole QT 5 QT 6 QT 7 QT 8 Eff. Space (mm) 20/20 39/75/39 Eff. Pole length (mm) CEPC-SPPC Beihang University Field gradient 73. 5/74/7 73/75/73 73/74/73 (T/m) 3. 5

Particle No. 98449 95% 99. 9% CEPC-SPPC Beihang University

Particle No. 9843 CEPC-SPPC Beihang University

Energy spectrum CEPC-SPPC Beihang University

Bunch Center CEPC-SPPC Beihang University

Emittance CEPC-SPPC Beihang University

CEPC-SPPC Beihang University

Voltage & Field CEPC-SPPC Beihang University

CEPC-SPPC Beihang University

Transit Time Factor (TTF) CEPC-SPPC Beihang University

CEPC-SPPC Beihang University

• SPPC i-Linac RFQ Main Parameters Versus Cell Number CEPC-SPPC Beihang University

• SPPC i-Linac RFQ Beam Dynamics Parameters SPPC i-Linac RFQ Particle U 40+ Frequency 81. 25 [MHz] Injection Energy 5 [AKe. V] Output Energy 300 [AKe. V] Beam Current 3 [em. A] Vane Length 3. 487 [m] Norm. RMS Input Emittance 0. 2 [mm. mrad] Vane Voltage 85 [KV] Peak Surface Field 17. 83 [MV/m] (1. 69 Ek) Aver. / Min. Aperture 5. 871 / 5. 161 [mm] Transmission Efficiency 95. 4% [88. 8%, 6 em. A] Energy Spread 0. 4% CEPC-SPPC Beihang University

• SPPC i-Linac RFQ Beam Transport Simulation (1/3) CEPC-SPPC Beihang University

• SPPC i-Linac RFQ Beam Transport Simulation (2/3) CEPC-SPPC Beihang University

• SPPC i-Linac RFQ Beam Transport Simulation (3/3) CEPC-SPPC Beihang University

RFQ Exit QT 1 DIA. 20 mm CEPC-SPPC EFF. LGTH. 80, 160, 80 mm FIELD GRAD. 3950, -3100, 3405 Bunc Beihang University her EFF. GAP Volt. 0. 043 MV Drift QT 2 Buncher Drift QT 1 Diagnostics • The MEBT Design between RFQ Exit and IH-DTL QT 2 Entrance DIA. 20 mm EFF. LGTH. 80, 160, 80 mm FIELD GRAD. -3594, 2534, 2215

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