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bnl - fnal- lbnl - slac
TQC Design – Details and Plans
R. Bossert
DOE Review
November 1-4, 2005
TQC objectives
• TQC magnets are technological quadrupole models based on the collar-
yoke-skin mechanical structure
• Design goals
– Achieve Gmax>200 T/m.
– Fabricate, test and evaluate 2-layer shell-type coil design without
internal interlayer splices
– Fabricate, test and evaluate mechanical structures based on collar-
yoke-skin support.
– Develop and evaluate coil fabrication and magnet assembly
technologies
• Performance study:
– magnet quench performance: training, re-training, SSL
– field quality: geometrical harmonics, coil magnetization, iron
saturation, alignment, field quality correction
– quench protection: conductor parameters, quench heaters
• Compare TQC and TQS designs, technology and performance parameters
DOE Review - November 1-4, 2005 TQ Collar Design – Details and Plans R. Bossert 2
TQC01 coil
Coil:
– 2-layer shell-type
– Inner-layer wedges
– Inner-layer pole glued into the
coil
Cable:
– Strand – MJR, 0.7 mm
– Number of strands – 27
– Keystone angle – 1 deg
– Width – 10.077 mm
– Thickness – 1.26 mm
Insulation: 0.125 mm S2-glass sleeve
Identical to TQS coils.
DOE Review - November 1-4, 2005 TQ Collar Design – Details and Plans R. Bossert 3
TQC01 parameters
TQC01 Specifications
Unit TQC01
Parameter
Number of layers 2
Number of turns 136
Coil area (Cu + non Cu) cm2 29.33
Assumed non-Cu Jc at 12T, 4.2K kA/mm2 2.0
Quench Gradient 4.2K/1.9K T/m 215.6/233.1
Quench Current 4.2K/1.9K kA 12.94/14.07
Peak field in the coil at quench 4.2K/1.9K T 11.2/12.1
DOE Review - November 1-4, 2005 TQ Collar Design – Details and Plans R. Bossert 4
TQC design approach
TQC design is based on the
MQXB mechanical
structure (collar, yoke,
skin, end plate, etc.).
TQC uses available coil
winding and curing
tooling (winding tables,
mandrels, presses, etc.).
Mechanical structure,
tooling and infrastructure
MQXB cross-section. exist for 1-2 m long and
up to 6 m long magnets.
DOE Review - November 1-4, 2005 TQ Collar Design – Details and Plans R. Bossert 5
TQC mechanical structure
Stress Relief Slot • Modified MQXB collar blocks
Skin in inner pole
with outer-layer poles for coil
alignment. Inner-layer poles
Preload are glued into the coil.
Shim • Radial yoke cut per quadrant to
Yoke
Gap provide symmetrical load.
• Control spacers for collared
coil alignment and yoke
Collaring
Yoke Key motion control.
• Preload shim at each midplane
Control Collar to control coil-yoke
Spacer interference.
• 12 mm thick stainless steel
skin.
• Mechanical structure and coil
pre-stress are being studied
and optimized using short (~40
cm) mechanical model.
DOE Review - November 1-4, 2005 TQ Collar Design – Details and Plans R. Bossert 6
TQC Assembly
• Impregnated coils are assembled and surrounded by layers of Kapton ground wrap.
• Assembly is hung vertically over collaring press, and collar packs are placed over coils.
• Collars are incrementally keyed, in 3 inch longitudinal sections, applying azimuthal preload to
the coils of 70MPa after keying is complete.
• Control spacers, preload shims, yoke packs and skin are assembled in press.
• Hydraulic pressure is applied and skin is welded, applying the fully assembled preload of
140MPa to the coil through the preload shims.
• Preload to coils from yoke/skin is limited by the control spacers at room temperature.
• During cooldown, parts shrink, allowing preload on coils to increase to 150MPa.
Stress Relief Slot
250 um mil in inner pole
Skin
kapton trace
125 um (removed in pole area)
kapton sheet Preload
Shim
Yoke
Gap
Collaring
Yoke Key
Control Collar
250 um ceramic Spacer
sheet bronze inner pole
DOE Review - November 1-4, 2005 TQ Collar Design – Details and Plans R. Bossert 7
TQC Mechanical Analysis
Stresses in coil and
components derived
from Finite Element
Analysis. All stresses
are well below yield
strength of material.
Stresses in TQC01 Coils and Components (MPa)
4
6 Max/Min At Pole Control Collar Yoke Skin
5
3 Coil Coil insert Spacer (Avg)
Stress Pos.
No.
300K 140/65 3/1&2 250 50 420 170 150
1 2 4.2K 150/80 3/1&2 230 80 470 270 270
Bmax 145/10 2/3 10 50 460 280 300
DOE Review - November 1-4, 2005 TQ Collar Design – Details and Plans R. Bossert 8
TQC Forces when Powered
DOE Review - November 1-4, 2005 TQ Collar Design – Details and Plans R. Bossert 9
TQC – Mechanical Model
Work is underway on a mechanical model to test these assumptions.
A dry run with an instrumented aluminum tube has been completed.
Strain in the aluminum tube was measured while the collaring keys
were inserted, incrementally, in 3mm steps until they were fully
inserted. Azimuthal stress in the aluminum tube increased by
approximately 10 MPa per mm of key depth. Since key depth can be
controlled during the keying operation to about 1mm, the incremental
stress between keyed sections can be controlled to within 10 MPa.
DOE Review - November 1-4, 2005 TQ Collar Design – Details and Plans R. Bossert 10
TQC analysis – Mechanical Model
Mechanical model assembly
with instrumented practice
coils is currently taking
place.
DOE Review - November 1-4, 2005 TQ Collar Design – Details and Plans R. Bossert 11
TQC End Loading
End load is applied by a combination of radial force through the collars by the skin,
and end force applied by four preload screws, or “bullets” through 50mm thick
stainless steel end plates. A total force of 14000N (3000 lbs.) is applied to each end.
This system is identical to that used for Nb3Sn dipoles at Fermilab. HFDA06, the
most recent dipole model, was tested with this system and remained preloaded
during all phase of operation.
Skin
Bullets Yoke End Plate
14000 N 14000 N
Bullet Preload Plate
Collars
DOE Review - November 1-4, 2005 TQ Collar Design – Details and Plans R. Bossert 12
TQ Coil Fabrication Experience
• The TQ coil manufacturing has been very
successful to date. LBNL and FNAL have
successfully collaborated on their
completion, with technicians from both labs
present throughout the fabrication process.
• 4 practice coils have been manufactured.
• 3 coils made of MJR strand for TQS01
have been wound and cured. The 4th is
currently being wound.
• A complete coil traveler is written and
incorporated into the fabrication process.
DOE Review - November 1-4, 2005 TQ Collar Design – Details and Plans R. Bossert 13
TQ Coil Fabrication Experience - Winding
Some issues were identified and resolved during the practice coil manufacturing
process:
• Gaps between turns and end parts appeared on practice coil #1 due to the necessity
of grinding parts to place them onto the uncompressed coil during winding, a
common practice when making Nb3Sn coils. This problem has been solved by
cutting slots into certain end pats to make them more flexible.
• There were some instances of de-cabling during winding. They were controlled with
winding techniques, primarily reducing winding tension at critical moments, adding a
360 degree twist between the cable tensioning device and the coil during winding, and
changing the system which measures tension, allowing the cable to take a straight path
directly from the tensioner to the coil, rather than passing through a series of rollers.
DOE Review - November 1-4, 2005 TQ Collar Design – Details and Plans R. Bossert 14
TQ Coil Fabrication Experience - Winding
• Ramp area between inner and outer coils deformed, during curing on early
practice coils. Practice coil #2, which later exhibited tin leaks, showed significant
damage. New tooling, incorporated in practice coil #4, alleviated stresses in this
area and eliminated the deformations.
Practice Coil #2
Practice Coil #4
DOE Review - November 1-4, 2005 TQ Collar Design – Details and Plans R. Bossert 15
TQ Coil Fabrication Experience - Curing
After winding, cable insulation is injected with ceramic binder, then coils are cured
at 150C for 30 minutes in a closed cavity mold, subjected to an azimuthal pressure
of approximately 35 MPa.
Curing is done to set the coil size for reaction, as well as allow the coils to be
easily handled, facilitating insertion into the reaction fixture without damage.
Curing operation went well. All coils
were measured following curing
before reaction.
DOE Review - November 1-4, 2005 TQ Collar Design – Details and Plans R. Bossert 16
TQ Coil Fabrication Experience - Measuring
After curing, azimuthal measurements of the coils
are taken. Measurements are taken in 3 inch
increments over the entire coil straight section at
pressures of 8, 10,15 and 20 MPa.
Measurements are defined as the arc length of one
side of a coil (one octant), compared to a steel
master of the nominal coil size.
Since the TQ coils
have pole pieces
potted into them, it
is not possible to
measure each side
separately. Coils are
measured as shown,
and averaged to
obtain the single
side measurement.
DOE Review - November 1-4, 2005 TQ Collar Design – Details and Plans R. Bossert 17
TQ Cured Coil Measurements
Coil measurements are done for several reasons:
• To verify coil size and
consistency. TQ Coil Size vs. Pressure
Size shown per side vs. master with respect to nominal
• To determine the amount to -100
shim the coil within the -150
reaction fixture to ensure
Size (Microns)
-200
that an appropriate amount Prac1
of pressure is being applied
-250
Prac2
during the reaction process. -300 Prac3
-350 Prac4
•To feed back information for -400 TQSCW05
adjustments in future coil TQSCW06
-450
sizes to obtain proper
-500
preload without shimming,
optimizing field quality. 0 5 10 15 20 25
Pressure (MPa)
•To test for turn-to-turn
shorts under load.
DOE Review - November 1-4, 2005 TQ Collar Design – Details and Plans R. Bossert 18
TQ Coil Fabrication Experience
• The practice coils #1 and #3 were reacted and impregnated at Fermilab. After
reaction before impregnation and after impregnation coils were inspected and
looked good. Techniques are documented and being incorporated into a traveler to
be used for the real TQ coils.
DOE Review - November 1-4, 2005 TQ Collar Design – Details and Plans R. Bossert 19
TQ Coil Fabrication Experience
• Pictures of the cut surfaces of the impregnated coils have been taken with a
microscope, showing impregnation to be complete
These pictures
demonstrate
that epoxy
penetrated
inside the cable.
DOE Review - November 1-4, 2005 TQ Collar Design – Details and Plans R. Bossert 20
TQ Impregnated Coil Measurements
• After impregnation, Practice coils #1 and #3 were measured and monitored for
resistance at the same pressures done after curing.
TQ Coil Size vs. Pressure - Impregnated TQP-CW-03 Size vs. Pressure - impregnated
Size shown per side vs. master Size shown per side vs. master
50 50
40 40
30 30
Size (Microns)
20 20
Size (Microns)
10
10
0
Prac1 0
-10
-20
-10 0 5 10 15 20 25
Prac3 -20 Pos 1
-30 Pos 2
-40 -30 Pos 3
-50 -40 Avg.Size (um)
0 5 10 15 20 25 -50
Pressure (MPa) Pressure (MPa)
DOE Review - November 1-4, 2005 TQ Collar Design – Details and Plans R. Bossert 21
Summary of Current Status
• 4 practice coils were successfully wound and cured at Fermilab,
with the participation of technicians from both FNAL and LBL.
• Coils for TQS01 are currently being fabricated. The first three coils
are complete, with the fourth beginning this week. Coils can be
wound, cured and measured in 8 working days each, within the time
originally estimated.
• 8 UL of cable for TQS01/TQC01 are insulated and on hand at FNAL.
The remaining 2 UL have been fabricated by LBNL, and will be
shipped when insulation material arrives.
• 2 practice coils have been reacted, impregnated and measured at
Fermilab.
• 2 practice coils have been reacted and prepared for impregnation at
LBNL.
DOE Review - November 1-4, 2005 TQ Collar Design – Details and Plans R. Bossert 22
Next
• Last two TQS01 coils will be completed and shipped to LBNL by the
middle of November.
•TQC01 coils and two spare coils will be wound, reacted and potted. FY06
Q1/Q2
• TQC01 will be assembled and tested. FY06 Q2/Q3
• TQC02 coils will be wound, reacted and potted. FY06 Q2/Q3
• TQC02 will be assembled and tested. FY06 Q3/Q4
• TQC01 will be disassembled and the coils delivered to LBNL to use
in TQE01. FY06 Q3/Q4
• TQC03, another “identical” 2-layer quad, will be built and tested.
FY07 Q1-Q3
DOE Review - November 1-4, 2005 TQ Collar Design – Details and Plans R. Bossert 23
