The ISACII Accelerator

1
The ISAC-II Accelerator

• Bob Laxdal, TRIUMF

• Outline
• Overview of ISAC-II
• Status
• Latest Highlights
• Cryogenic system progress
• Cryomodule cold test
• Alignment Studies

2
Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF
3
Stage 0 - 2005
E4.5MeV/u A/q6
S0
Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF
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Stage 1 - 2007
E6.5MeV/u A/q7
S0
Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF
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ISAC-II SC Linac
Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF
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• Outline
• Overview of ISAC-II
• Status
• Latest Highlights
• Cryogenic system progress
• Cryomodule cold test
• Alignment Studies

Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF
7
ISAC-II Present Status

• SCRF development active in new lab
• High Beta Cavity design initiated
• 21 Medium ß Cavities received
• Eight production cavities BCP completed
• Remaining thirteen to receive BCP at JLAB
• First cryomodule being tested
• First cooldown April 23, 2004
• First rf cold test in June 2004
• Five medium ß and two high ß solenoids ordered
• Two received, two more expected next month
• Refrigerator contract awarded to Linde
• phase I 500W
• Due for commissioning in Dec. 2004

Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF
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ISAC-II Linac

• Composed of quarter wave bulk niobium cavities
  and superconducting solenoids housed in box-like
  cryomodules
• Initial installation of five medium beta
  cryomodules schedule for commissioning Nov. 2005
• Prototype medium beta cryomodule now being cold
  tested

Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF
9
Medium Beta Cryomodule

• First Medium beta cryomodule in assembly
• First cold test successfully completed April
  23-25
• Stainless steel vacuum enclosure
• LN2 cooled copper shield
• mu metal for magnetic field suppression

Lid Assembly in Assembly Frame
Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF
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Medium Beta Cavity

• Prototype developed in collaboration with A.
  Facco of LNL and fabricated in E. Zanon
• Simple construction suitable for industry
  production
• Twenty cavities received from E. Zanon in Italy
• Four BCP CERN, four BCP JLAB
• Remaining cavities to be polished at JLAB

Chemical Polishing at CERN
Frequency Measure at Zanon
Four Cavities at TRIUMF
Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF
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Cavity Performance

• All cavities meet or exceed the design gradient
  (6MV/m _at_7W) in off-line cold tests

Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF
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First Cold Test of Flattened Cavity

• Meets design goals Ea6MV/m _at_ lt7W

Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF
13
Everson Solenoid
Prototype Solenoid at Everson

• Medium beta prototype received incomplete from
  Everson Electric due to bankruptcy
• Solenoid was completed at TRIUMF
• Cold test results match design

Solenoid with Helium Reservoir
Axial Field Map
Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF
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Superconducting Solenoids
Prototype Solenoid at Accel

• Focussing in the SC Linac is provided by
  superconducting solenoids (B?9T)
• End fringe fields controlled with active
  bucking coils (Bcavity?0.1T)
• Medium beta prototype received incomplete from
  Everson Electric due to bankruptcy
• Production Medium and high beta solenoids in
  fabrication at Accel
• See table for specifications

Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF
15
RF Systems
Forward power required for Ea6MV/m and given
bandwidth

• RF power
• Provide useable bandwidth by overcoupling
• Require Pf 200W at cavity for f 1/220Hz at
  Ea6MV/m, ß200
• Coupling loop
• Developing LN2 cooled loop
• Achieved lt0.5W to LHe for Pf250W
• Mechanical tuner
• Precise (0.3Hz), fast (gt5Hz/sec) tuner with
  dynamic range of 8kHz and coarse range of 32kHz
• Tuning plate
• Spun, slotted, oil-can tuning plate to improve
  tuning range

Coupling Loop
Mechanical Tuner
Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF
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ISAC-II Mechanical Tuner

• Deflects niobium tuning plate at base of cavity
  (6 Hz/µm)
• Lever mechanism with zero backlash hinges and
  stiff rod connected to precision linear motor
  (Kollmorgan) in air
• In cold tests control loop was phase locked and
  tuner maintained frequency during rapid forced
  helium pressure fluctuations (1Hz/Torr)

f1/225Hz
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Coupling Loop with Direct Cooling

• Developed from INFN Legnaro adjustable coupling
  loop
• Modifications
• Stainless steel body for thermal isolation
• Copper outer conductor thermally anchored to
  copper LN2 cooled heat exchange block
• Aluminum Nitride dielectric inserts thermally
  anchor the inner conductor to the outer conductor
• Removed fingerstock to control microdust
• Achieved lt0.5W helium heating with Pf250W

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• Outline
• Overview of ISAC-II
• Status
• Latest Highlights
• Cryogenic system progress
• Cryomodule cold test
• Alignment Studies

Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF
19
Cryogenic System

• The cryogenic system will be installed in two
  equal stages
• Timing will follow staged installation of linac
• Smooths cash flow
• Allows redundancy in final configuration

Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF
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Cryogenic Loads (Phase 1)
13W
13W
13W
13W
13W
14W
14W
3W
24W
24W
24W
24W
24W
36W
36W
6W
CM1
CM6
CM2
CM3
CM4
CM5
CM7
Medium Beta (4)
High Beta (6)
96W
Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF
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Cryogenic Loads (Phase 12)
13W
13W
13W
13W
13W
14W
14W
3W
15W
2W
2.W
3W
22W
8W
64W
8W
0W
0W
64W
32W
32W
32W
32W
32W
48W
48W
CM1
CM6
CM2
CM3
CM4
CM5
Medium Beta (4)
High Beta
CM7
530W
Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF
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Phase 1 Refrigerator

• TC50 comprises
• Cold box
• Main compressor
• Kaeser ESD441
• Recovery compressor
• Kaeser BSD62
• ORS and gas management system
• TRIUMF to install Linde components plus
• Helium dewar, buffer tank, warm piping and cold
  distribution

Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF
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ISAC-II Building
f1/225Hz
f1/225Hz
f1/225Hz
Compressor Room
Buffer Tanks
Refrigerator Room
Linac Distribution
Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF
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Cold Distribution
Cold Helium Return
LHe
CM1
CM2
CM3
CM4
Cold Box
Dewar
Warm Helium Return

• Parallel supply feed from dewar through main
  header (4.5K)
• Cold helium return (lt20K) during normal operation
• Warm helium return (gt20K) to compressor suction
  used during cooldown and for power lead cooling

Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF
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Cold Distribution Cryomodule

• Individual vacuum jacketed lines for supply and
  return
• U-tubes for supply and return to cryomodule from
  main trunk-line

Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF
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Cryogenic Distribution (Phase 1)

• Specification in preparation
• Required for June 2005

Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF
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Cryomodule Distribution

• Cryomodule cooled by forcing helium vapor to
  bottom of each cold element with a distribution
  spider

Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF
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• Status
• Phase I refrigerator expected July 2004
• Commissioning expected before year end
• Warm piping, buffer tank, helium dewar
  specifications ready for issue
• Cold distribution in design
• First cooldown of cryomodule complete

Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF
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Cryomodule Cooldown

• Expected static loads
• Med. Beta Cryomodules
• load to helium - 13W/module
• 6 ltr/hour LN2
• First cooldown April 23-25/ 2004
• Alignment of cold mass measured by Wire Position
  Monitor (WPM) System

Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF
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Vacuum Tank

• 1.9cm thick stainless steel (316L) with external
  reinforcing ribs
• L176cm, W99cm, H196cm
• All services through 44 flanged ports on lid

Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF
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Assembly Frame
Cryomodule Assembly Frame

• For clean room assembly of cryomodule lid and
  contents including rf cavities and solenoid
• Top mounting surface and end plates mimic the
  vacuum tank top flange and beam ports for
  pre-alignment of cavities

Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF
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Nitrogen Heat Shield

• 10mm ID copper tube soldered to copper sheet
  arranged in a box-like structure
• Copper nickel plated to reduce emissivity
• Solder applied on hot table without flux in inert
  gas environment
• Copper cooling tubes run in series
• L36m
• ?P1.9PSI warm and 0.1PSI cold

Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF
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Cryomodule Alignment
WPM Monitors on Cavities

• the tolerance on solenoid and cavity
  misalignments are ?200 ?m and ?400 ?m
  respectively
• we are collaborating with INFN Milano on the
  development of a Wire Position Monitor for cold
  alignment with precision of 20 ?m
• Stripline monitor attached to each device driven
  by rf signal along a reference wire

Plan View
WPM
RF shield
Wire Position Stripline Monitor
Optical target
solenoid
cavities
Optical target
Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF
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Medium Beta Cryomodule

• First Cooldown preparation
• Pumpdown April 1
• LN2 cooldown April 8-10, April 18-20, May 2-6
• LHe cooldown April 23-25

Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF
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Cryomodule Pre-cool Test

• Cryomodule cooled with Helium April 23/04
• Pre-cool manifold and spider worked well to
  cool cavities and solenoid uniformally

Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF
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• Pre-cool manifold and spider worked well to
  cool cavities and solenoid uniformally

Cooldown Temperatures Main Components
Solenoid
Reservoir
Helium flow
Time (hours)
Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF
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Cryomodule Static Load

• April 25 First cooldown
• Cooldown and fill consumed 1400ltr LHe
• 200ltr liquid He accumulated in cryomodule
• After thermalization boil-off equivalent to 10W
  static load

Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF
38
LN2 Consumption

• Regulated exhaust flow at constant pressure
• 6.2ltr/hour produced 80K shield
• 4.7ltr/hour warmed shield to about 120K

Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF
39
Cold Alignment Test

• Cold Alignment Cycles
• LN2 cooldown April 8-10, April 18-20, May 2-6
• LHe cooldown April 23-25

Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF
40
Alignment Calibration

• Optical targets in first and last cavity were
  periodically measured with telescope to calibrate
  the temperature contraction of WPM brackets

WPM1 vs West Cavity Target - Horizontal
WPM6 vs East Cavity Target Vertical
WPM1 vs West Cavity Target
Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF
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Alignment Repeatability

• Cryomodule thermally cycled three times from room
  temperature to LN2 temperature
• WPM data analyzed to note repeatability of
  alignment at cold temperatures
• Alignment repeatable to within 80microns
  vertically and to within 120microns horizontally

Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF
42
Cooldown Summary

• First cooldown went smoothly
• Vacuum - 5e-9Torr when cold
• Static load to liquid helium after thermalization
  - 10W
• LN2 flow to thermal shield 5ltr/hour
• Cold alignment studies using WPM in progress
• Rf test of the first cryomodule is scheduled for
  June

Bob Laxdal, The ISAC-II Accelerator, ACOT, May
14,2004, TRIUMF