Thomas Jefferson National Accelerator Facility Page 1SPL Cryogenic and vacuum sectorisations 9-10 November, 2009

Joe Preble

Workshop on cryogenic and vacuum sectorisations of the SPLNovember 9-10, 2009

Jefferson Lab Experience

Thomas Jefferson National Accelerator Facility Page 2SPL Cryogenic and vacuum sectorisations 9-10 November, 2009

Outline: CEBAF cryogenic and vacuum system

Description

Operating experience

Configuration sensitivities

Thomas Jefferson National Accelerator Facility Page 3SPL Cryogenic and vacuum sectorisations 9-10 November, 2009

Description

Thomas Jefferson National Accelerator Facility Page 4SPL Cryogenic and vacuum sectorisations 9-10 November, 2009

CHL System Schematic

Primary Circuit ~180 g/s-linac (2 linacs)Supply3.2 atm~3 KReturn2.1 K

Thomas Jefferson National Accelerator Facility Page 5SPL Cryogenic and vacuum sectorisations 9-10 November, 2009

LINACs Configuration

690W @2.1K on SL

27 ¼ Cryomodules

25 Cryomodules

3 ¼ Cryomodules

Total of 57 independent Cryostats

Thomas Jefferson National Accelerator Facility Page 6SPL Cryogenic and vacuum sectorisations 9-10 November, 2009

CHL Capacities

• Current 6 GeV (CHL #1)• Load: 4248W @ 2.1K, 11648 W @ 50K• Capacity: 4600W @2.1K, 12000W @ 50K

• New 12 GeV (CHL #1 + new CHL#2)• Load: 7400W @ 2.1K, 14650W @ 50K• Capacity: 9200W @ 2.1K, 24000W @ 50K

Thomas Jefferson National Accelerator Facility Page 7SPL Cryogenic and vacuum sectorisations 9-10 November, 2009

Cryomodule Description: 10 m pitch

• 8 cavities and power couplers• 2 cryogenic circuits, 2K & 50K• 4 U-tubes supplying cryogens, 2 supply and

2 return• 2 beamline warm to cold transition with

isolation valves• 3 independent vacuum systems, beamline,

power coupler, and insulating vacuum• ~1m warm beamline between cryomodules

Thomas Jefferson National Accelerator Facility Page 8SPL Cryogenic and vacuum sectorisations 9-10 November, 2009

Cryomodule Description

Beamline thermal transition

2 Isolation valves, 1 cold needed for assembly,1 warm needed for installation

Thomas Jefferson National Accelerator Facility Page 9SPL Cryogenic and vacuum sectorisations 9-10 November, 2009

Cryomodule Description: 2K circuit

JLAB C100 Cryomodule

SNS End Cans

Return end includes heat exchanger, real improvement in design over CEBAF CM

2 Headers5” ½ filled with liquid and 1”completely filled with liquid

Thomas Jefferson National Accelerator Facility Page 10SPL Cryogenic and vacuum sectorisations 9-10 November, 2009

Transfer Line

LINAC 6” Return Line CHL 8” Return Line

LINAC 1” Supply

Thomas Jefferson National Accelerator Facility Page 11SPL Cryogenic and vacuum sectorisations 9-10 November, 2009

Loads/Capacities: 6GeV/12GeV Breakdown

12 GeV Unit Loads 6 GeV North Linac South Linac 2 K 50 K # 2 K 50 K # 2 K 50 K # 2 K 50 K

Loads (#,W) Static Transfer Line 530 6360 1 530 7000 0.57 228 3990 0.43 302 3010 Original CM’s 16 110 42.25 676 4648 21.25 340 2448 20 320 2200 12 GeV CM’s 18 250 6 108 1250 5 90 1250 Dynamic

Original CM’s 72 40 42.25 3042 21.25 1530 850 20 1440 800 12 GeV CM 250 50 6 1500 300 5 1250 250

Totals 42.25 4248 11648 25.25 3706 7988 29.25 3402 6710

Capacities (W)

CHL#1 (W) 4600 12000 4600 12000

% of Full Load 92% 97% 85% 67% CHL#2(W) 4600 12000 % of Full Load 77% 56%

Thomas Jefferson National Accelerator Facility Page 12SPL Cryogenic and vacuum sectorisations 9-10 November, 2009

Operational Experience• Installation and commissioning

• Original installation and commissioning was completed in sections as we built cryomodules and cryo plant, injector first, ~ ½ first linac, …, saving considerable amounts of time

• Remove and replace cryomodules with the linac cold• 3 days to remove a cryomodule and install a drift tube• ~week to replace a cryomodule and cool down to 2 K

• Maintenance activities • Can include cryomodule work requiring a thermal cycle,

~week• Response to loss of power ….., hurricanes in our case

Thomas Jefferson National Accelerator Facility Page 13SPL Cryogenic and vacuum sectorisations 9-10 November, 2009

Operational Experience

• Refurbishment program started after ~15 years of operations, remove 1 or 2 cryomodules and completely rework them, 10 over 3 years

• Increased machine energy• Benefit from current processing technologies• replace o-rings, pumps, gauges, …

• Upgrade • Add additional cryomodules over time• Cool down when wanted

Thomas Jefferson National Accelerator Facility Page 14SPL Cryogenic and vacuum sectorisations 9-10 November, 2009

Configuration SensitivitiesModel LINAC performance based on SNS and CEBAF

LINACs, Spreadsheet model available for discussion, sample below

length, m ea        

cavitiy length in cm, m 1.3 5.2 10.4 20.8 41.6

quad length (every 4th cav) 0.8 0.0 0.8 1.6 3.2

Beamline transition, m 0.8 1.6 1.6 1.6 1.6

 

Total length per cm, m 6.8 12.8 24.0 46.4

Total cm length in linac, m 340.0 320.0 300.0 290.0

warm spacing between cm 1.0 50.0 25.0 12.5 6.3

Total linac length 390 345 313 296

Distribution costs 1470 1185 1013 926

Total Cost cm+dist 46470 44935 43513 42801

Thomas Jefferson National Accelerator Facility Page 15SPL Cryogenic and vacuum sectorisations 9-10 November, 2009

Configuration SensitivitiesDuty Cycle determines cryo load# of cavities in a cryomodule has little effect on the cryo load

Total Cryo Load with # of Cavities/cm and Operating Duty Cycle

0

5000

10000

15000

20000

0 1 2 3 4 5

Cavities per Cryomodule, 1=4, 2=8, 3=16, 4=32

Watt

s

2000

2100

2200

2300

2400

2500

2600

100% Duty Cycle

50% Duty Cycle

25% Duty Cycle

12.5% Duty Cycle

12.5 % is on separate scale for clarity

Thomas Jefferson National Accelerator Facility Page 16SPL Cryogenic and vacuum sectorisations 9-10 November, 2009

Configuration SensitivitiesUsing 12.5 % Duty Cycle

Configuration Sensitivities

200

250

300

350

400

450

500

0 5 10 15 20 25 30 35

# of Cavities in a Cryomodule

0.0%

2.0%

4.0%

6.0%

8.0%

10.0%

12.0%

Length (m)

Cost CM + DIST (k$/100)

2K Watts/10

Dist. Sys @ 12.5% Ops (%)

Costs 43-47 M$Watts 2.3-2.5 kWDist Sys % of Total on second scale for clarity, 2-9 %