Bri XS Mari X WG 8 9 LASA

Bri. XS – Mari. X WG 8, 9 LASA December 13, 2017

Reference machines • Three families of SC cavities could be foreseen • Bri. XS cavities: zero beam-loading, high-current, heavily damped HOMs, Energy Recovery • • LERF (JLAB), in operation at 10 m. A c. ERL (KEK), in operation at 1 m. A, not yet at nominal current of 100 m. A CBeta (Cornell), multi-pass ERL demonstrator, linac module tested, DR released BERLin. Pro (HZB), under costruction, CDR released • Mari. X cavities • Moderate beam loading, moderate current, possibly standard TESLA cavity (RF geometry) • LCLS-II • Booster module (not considered) • If a booster module is required: Less cells, high-power, full beam-loading • c. ERL (KEK), CBeta (Cornell) • Bottom-lines • TESLA/European-XFEL is mostly the reference

BRIXs linacs

CBETA, Cornell • Linac Module: • 6 7 -cells cavities, custom cavity RF shape • Design Limit beam current of 100 m. A (one pass) • Limit down to 40 m. A for 4 -passes • Beam test, no ERL, low current • CW, 16 MV/m gradient, up to 75 Me. V • 5 k. W forward RF power for each cavity • Commercial Solid State Amplifier, Qext 6 e 7 • Nominal Q 0 at 2 e 10 at 1. 8 K • HOM absorbers rings: • Up 400 W each • <12 W @ 40 m. A, single cavity test • Cooled at 80 K by 20 bar g. He

CBETA, Cornell • 80 K heat load finally goes to LN 2 • one g. He/LN 2 heat-exchanger for the CM • 13600 m 3/h subcooling pumping system • 4 systems in parallel, 3400 m 3/h Roots backed by 850 m 3/h rotary • Margin required by Q 0 that is not met (not doped cavities) • One of a kind module

c-ERL, KEK f 80 HOM damper • Linac Module: • 2 9 -cells cavities, TESLA shape (cells) • Limit beam current of 100 m. A • ERL beam test done up to 1 m. A • CW, 15 MV/m gradient, 20 to 30 Me. V • Actually limited to 8 MV/m by FE • Q 0 > 1 e 10 at 2. 0 K • 3 Ferrite HOM absorbers per module • up to 160 W dissipated power each • Isolated from the cavity • Cooled directly by liquid nitrogen HOM damper

c-ERL, KEK • Separate LN 2 feed-throughs and circuitry required for HOM absorbers • Poor Eacc and Q 0 compared to non HOM-damped TESLA cavities • One of a kind

BRIXs - comments • CBETA Cornell: 2 more cavities required for 100 Me. V • 6 to 8 cavities string, from 10 to 13 m length • Not a dramatic change but yet not the very same object … • c. ERL KEK: For A 100 Me. V final energy… • linac could be assembled by 3/4 existing 2 -cavity modules to stay on the safest side • Much higher thermal loads • Redesign vacuum vessel with 6/8 cavities in a string • Once more, not critical but… • Ongoing activity at KEK

LHe Cryo plant – BRIXs Parameter Cavity temperature K Q 0 LCLS-II-type concept c. ERL-like CBETA-like 2. 0 1. 8 1 e 10 2 E+10 Accelerating E field MV/m 12. 5 15. 4 Power, cavity W 16. 6 17. 2 10. 1 # modules 2 8 2 # cavities 16 16 16 Energy, Total Ge. V 0. 200 Cryo power, total: only cavities, no HOM heat-load k. W 0. 266 0. 276 0. 161 Cryo power, total: cavities, distribution, feed-boxes, end caps k. W 0. 326 0. 436 0. 221 Cryo power, with margins: +30% static, +10% dynamic (LCLS-II) k. W 0. 366 0. 490 0. 248 Cryo power, plant: rated capacity at cavity temperature k. W 0. 4 (+50 l/h LHe*) 0. 5 (+50 l/h LHe*) 0. 25 (+50 l/h LHe*) AC plug power, 4. 5 K refrigerator MW 0. 7 0. 85 AC plug power, 1. 8 K or 2. 0 K refrigerator MW 0. 15 AC plug power, water cooling MW 0. 1 AC plug power, Total: sum of above MW 0. 9 1. 1 * Liquefaction required by concurrent activities (single cavity VTs, magnet cold tests etc. )

LHe Cryo plant – BRIXs - Actual machines • Cold compressors: • Used above 300 W cryogenic power • Typically 3, 2 -3, 6 W@4, 5 K/W@1, 8 K • FNAL Cryo. Module Test Facility: • 500 W @ 2, 0 K or 250 W @ 1, 8 K • 460 l/h liquefier mode • 3 -stage cold compressor • Largest off-the-shelf unit: LINDE L/LR 280 • 280 l/h, theoretically up to 900 W @ 4, 5 K • One in magnet test-stand at INFN-Salerno (200 W @ 4. 5 K)

Considerations on AC plug power requirements - BRIXs • Only CRYO and RF! • Liquid Nitrogen plant not investigated (LHe refrigerator pre-cooling and up to 7 k. W @ 80 K for HOMs) • RF amplifier • 16 single cavity RF SSA, 5 k. W forward and 12. 5 k. W plug power each • 0. 2 MW for the two linac modules • Overall Source Power – MW Linacs cryo 0. 8 Linacs RF 0. 2 Booster RF (2 x) 0. 8 Gun (2 x) 0. 3 Total: sum of above 2. 1 Cooling 0. 2 Total, with margin: to the user 2. 5 Installed: electrical grid substation, considering high inductive loads 8

MARIX linac

LCLS-II, SLAC • CW, 16 MV/m, 9 cells, 1. 3 GHz • TESLA cells, minor modifications for CW • Larger pipes, dual inlets, etc. • 3. 8 k. W forward RF power each cavity • Commercial SSA, Qext 4. 1 e 7 • Q 0 at 2. 7 e 10 at 2. 0 K (doped cavity) • Linac Module has 8 cavities • Design beam current of 100 m. A • upgrade foreseen to 300 m. A • Module string includes • • SC quad magnet BPM 1 HOM beam-pipe absorber Dual cryogenic feed-box

LCLS-II, SLAC • 35 CMs, 280 1. 3 GHz cavities • 1 3. 9 GHz module • 2 bunch compression chicanes • Linac foot-print • Using the first part of original LCLS tunnel at SLAC • Cutting LCLS-II at 2. 4 Ge. V, 19 CMs: • Total length approximately 500 m • Without undulators, photon beam lines, user’s facility etc.

LHe Cryo plant – MARIX 1. 3 GHz SC linac Parameter Cavity temperature K Q 0 LCLS-II MARIX – low risk MARIX – medium risk 2. 0 2. 7 e 10 Accelerating E field MV/m 16 16 20 Power, cavity W 10. 1 13. 6 15. 8 # modules 35 19* # cavities 280 152 Energy, Total Ge. V 4. 5 2. 4 3. 0 Cryo power, total: only cavities k. W 2. 83 2. 07 2. 40 Cryo power, total: cavities, distribution, feed-boxes, end caps k. W 3. 64 2. 97 Cryo power, with margins: +30% static, +10% dynamic (LCLS-II) k. W 4. 09 2. 97 3. 33 Cryo power, plant: rated capacity at cavity temperature k. W 2 x 4 (JLAB CHL 2) 1 x 4 (JLAB CHL 2) AC plug power, cryogenic plant MW 9 4. 5 AC plug power, water cooling MW 1 0. 5 AC plug power, Total: sum of above MW 10 5 5 * Assuming 15 m each unit, the cryomodule string itself extends for 285 m

Considerations on AC plug power requirements - MARIX • Few changes from LCLS-II Parameter Unit Loaded Q Peak detuning Hz Number of cavities MARIX 4. 1 e 7 3. 25 e 7 10 30 280 152 Forward RF power, with margins: cavity k. W 3. 7 6. 0 Installed RF power: cavity k. W 3. 8 6. 2 2. 7 2. 4 Total, AC plug power: linac, 40 % SSA efficiency MW • MARIX 1. 3 GHz SC linac LCLS-II Source Power – MW Linac cryo 5 Linac RF 3 Electronics 2 Total: sum of above 10 Cooling 1 Total, with margin: to the user 14 Installed: electrical grid substation, considering high inductive loads 45