Download - Jefferson Lab Experience
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 %