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Superconducting Magnet Division
Ramesh Gupta Medium and High Field HTS Magnet R&D at BNL November 5, 2013 Slide No. 1 LTHFSW13
Medium and High Field
HTS Magnet R&D at BNL
Ramesh Gupta
BNL
Superconducting Magnet Division
Ramesh Gupta Medium and High Field HTS Magnet R&D at BNL November 5, 2013 Slide No. 2 LTHFSW13
Overview
• Variety of HTS Magnet Programs at BNL
• Focus of this Presentation
– Medium Field HTS Quad for FRIB
• Significant test results
– High Field (>30 T) HTS Solenoid for MAP
• Continuation of PBL/BNL program under MAP funding
• Feedback to Conductor Manufacturer
• Summary
Superconducting Magnet Division
Ramesh Gupta Medium and High Field HTS Magnet R&D at BNL November 5, 2013 Slide No. 3 LTHFSW13
Active HTS Magnet Programs at BNL (1)
• HTS Solenoid for Energy Recovery Linac (ERL)
– To be inducted in a significant R&D facility at BNL shortly
• HTS Magnet for Synchrotron Radiation Source
– To be delivered to an experimental program at BNL shortly
• MgB2 Phase II SBIR (DOE/NP) with HyperTech
– Technology development to upgrade e-lens for RHIC at BNL
(high power required by copper solenoids not available locally)
Superconducting Magnet Division
Ramesh Gupta Medium and High Field HTS Magnet R&D at BNL November 5, 2013 Slide No. 4 LTHFSW13
Active HTS Magnet Programs at BNL (2)
• HTS Quad for FRIB at MSU (funded by DOE/NP)
– A major HTS program at BNL from last decade
• HTS Dipole Phase II SBIR (DOE/NP) with Muons, Inc.
– Longer length (>2m) radiation tolerant curved dipole for FRIB
• Development of Quench Protection Technology
– Partly supported by BNL internal program development funds
and partly by individual project funds to fulfill their specific
requirements (MAP, FRIB, ARPA-E and SBIR’s)
Superconducting Magnet Division
Ramesh Gupta Medium and High Field HTS Magnet R&D at BNL November 5, 2013 Slide No. 5 LTHFSW13
Active HTS Magnet Programs at BNL (3)
• High Field (>30 T) Solenoid for MAP
– PBL/BNL solenoid SBIRs (funded by DOE/HEP) created
record fields (~16 T peak insert, ~9 T peak half-midsert). The
goal is to use these existing coils to develop and demonstrate
technology for high field solenoid for MAP
• High Field (~24 T) HTS Solenoid for SMES
– A significant HTS R&D program in recent years. Program is
funded by DOE/ARPA-E (collaborators: ABB, BNL,
SuperPower, UH; BNL/SMD responsible for SMES coil)
Having acquired over 50 km of HTS (4 mm tape equivalent), made hundreds of
HTS coils and tens of HTS magnets, BNL has a unique experience with HTS.
Superconducting Magnet Division
Ramesh Gupta Medium and High Field HTS Magnet R&D at BNL November 5, 2013 Slide No. 6 LTHFSW13
HTS Quad for FRIB
Highlights:
• HTS Magnet built with significant amount
of ReBCO (2G HTS) from two vendors
• No observable degradation during winding,
cool-down or testing
• Large temperature margin - thanks to HTS
• Magnet survived several events (quenches?)
near or above design field
HTS coils in
support structure
Superconducting Magnet Division
Ramesh Gupta Medium and High Field HTS Magnet R&D at BNL November 5, 2013 Slide No. 7 LTHFSW13
Radiation Tolerant HTS Quad for the
Facility for Rare Isotope Beams (FRIB)
Exposure in the first magnet itself:
Head Load : ~10 kW/m, 15 kW
Fluence : 2.5 x1015 n/cm2 per year
Radiation : ~10 MGy/year
Pre-separator quads and dipole
To create intense rare isotopes, 400 kW beam hits the production target.
Several magnets in Fragment separator region (following the target) are
exposed to unprecedented level of radiation and heat loads.
Courtesy: Zeller, MSU
Radiation resistant
Court
esy: A
l Z
elle
r, F
RIB
/MS
U
Superconducting Magnet Division
Ramesh Gupta Medium and High Field HTS Magnet R&D at BNL November 5, 2013 Slide No. 8 LTHFSW13
Second Generation HTS Quad for FRIB (higher gradient and operating temperature)
Eight coils wound
4 coils made with ASC:
~210 m double sided
(420 m HTS per coil)
~2x125 turns
4 coils with SuperPower:
~330 m per coil
~213 turns
Note: This is a 12 mm tape
(3X the standard 4 mm)
First generation quad was made with the 1G HTS (Bi2223)
Higher performance 2nd generation quad is made with 2G HTS
(over 8 km of 4 mm equivalent used)
Superconducting Magnet Division
Ramesh Gupta Medium and High Field HTS Magnet R&D at BNL November 5, 2013 Slide No. 9 LTHFSW13
Completed Second Generation HTS Quad for FRIB
{8 racetrack coils, 4 made with SP tape and four with ASC tape (double)}
Superconducting Magnet Division
Ramesh Gupta Medium and High Field HTS Magnet R&D at BNL November 5, 2013 Slide No. 10 LTHFSW13
Test Results Large Temperature Margin
(+20% in Ic &
+10 K in Tc)
(+15% in Ic &
+20 K in Tc)
Design Current @38 K:
SuperPower 210 A
ASC (double tape) 310 A
(50K,375A)
(60K,240A)
• Magnet with significant amount of HTS performed well
• Unprecedented temperature margin – only possible with HTS
No observable
degradation
during cool-down
or energizing
Superconducting Magnet Division
Ramesh Gupta Medium and High Field HTS Magnet R&D at BNL November 5, 2013 Slide No. 11 LTHFSW13
-100
0
100
200
300
400
500
12:04:19 PM 12:05:02 PM 12:05:46 PM 12:06:29 PM 12:07:12 PM 12:07:55 PM 12:08:38 PM 12:09:22 PM 12:10:05 PM 12:10:48 PM 12:11:31 PM
Cur PS 2
-2
0
2
4
6
12:04:19 PM 12:05:02 PM 12:05:46 PM 12:06:29 PM 12:07:12 PM 12:07:55 PM 12:08:38 PM 12:09:22 PM 12:10:05 PM 12:10:48 PM 12:11:31 PM
-600
-500
-400
-300
-200
-100
0
100
12:04:19 PM 12:05:02 PM 12:05:46 PM 12:06:29 PM 12:07:12 PM 12:07:55 PM 12:08:38 PM 12:09:22 PM 12:10:05 PM 12:10:48 PM 12:11:31 PM
Event (Quench?) while ASC Coils were held at 382 A (design: 310 A)
Cu
rren
t (A
) C
oil
Vo
ltag
es
(m
V)
Zo
om
Slow logger:
One point/sec
Shut-off
Shut-off
Events prior
to Shut-off
Co
il V
olt
ag
es
(m
V)
Superconducting Magnet Division
Ramesh Gupta Medium and High Field HTS Magnet R&D at BNL November 5, 2013 Slide No. 12 LTHFSW13
Snap Shot of the Event in ASC Coils (individual and difference voltages)
-40
-20
0
20
40
60
80
1001 7
13
19
25
31
37
43
49
55
61
67
73
79
85
91
97
Vo
ltag
e (m
V)
Time (msec)
B-C, ACS-4
D-E, ACS-1
ASC1-ASC4
Dif
fere
nc
e V
olt
ag
e
Fast data logger:
One point/msec
Shut-off
Superconducting Magnet Division
Ramesh Gupta Medium and High Field HTS Magnet R&D at BNL November 5, 2013 Slide No. 13 LTHFSW13
-0.8
-0.6
-0.4
-0.2
0
0.2
1 7
13
19
25
31
37
43
49
55
61
67
73
79
85
91
97
Vo
ltag
e (m
V)
Time (msec)
ASC1-ASC4
Snap Shot of the Event (Quench?) that Triggered the Shut-off
-40
-20
0
20
40
60
80
100
1 7
13
19
25
31
37
43
49
55
61
67
73
79
85
91
97
Vo
ltag
e (m
V)
Time (msec)
B-C, ACS-4
D-E, ACS-1
ASC1-ASC4
-20
0
20
40
60
80
100
1 7
13
19
25
31
37
43
49
55
61
67
73
79
85
91
97
Vo
ltag
e (m
V)
Time (msec)
ASC1-ASC4
Difference Voltage
Low threshold (few hundred mV) can be kept
due to the advanced quench detection system
No degradation in performance observed after the event
Superconducting Magnet Division
Ramesh Gupta Medium and High Field HTS Magnet R&D at BNL November 5, 2013 Slide No. 14 LTHFSW13
-10
10
30
50
70
90
4:30 PM 4:31 PM 4:32 PM 4:32 PM 4:33 PM 4:34 PM 4:35 PM
170
175
180
185
190
16:30:43 16:31:26 16:32:10 16:32:53 16:33:36 16:34:19 16:35:02
-600
-500
-400
-300
-200
-100
0
100
16:30:43 16:31:26 16:32:10 16:32:53 16:33:36 16:34:19 16:35:02
Cu
rren
t (A
)
Voltage and
Voltage Difference (mV)
Voltage (mV)
and
Voltage Difference (mV)
Event (Quench?) During the Ramping of the SuperPower Coils
Zo
om
Slow logger:
One point/sec
Vacuum leak made the
temperature increase to
~57 K (design temp ~38 K)
Superconducting Magnet Division
Ramesh Gupta Medium and High Field HTS Magnet R&D at BNL November 5, 2013 Slide No. 15 LTHFSW13
Snap Shot of the Event (Quench?) that Triggered the Shut-off
-200
-100
0
100
200
300
400
5001 7
13
19
25
31
37
43
49
55
61
67
73
79
85
91
97
Vo
ltag
e (m
V)
Time (msec)
P-R, SP#1
S-T, SP#2
SP#1-SP#2
-10
0
10
20
30
40
50
1 7
13
19
25
31
37
43
49
55
61
67
73
79
85
91
97
Vo
ltag
e (m
V)
Time (msec)
P-R, SP#1
S-T, SP#2
SP#1-SP#2
7 per. Mov. Avg. (SP#1-SP#2)
Fast logger: One point/msec
Large inductive voltage in
individual coils (ramp)
Small quench detection
threshold (2 mV) kept during
the ramp by monitoring
difference voltage
Superconducting Magnet Division
Ramesh Gupta Medium and High Field HTS Magnet R&D at BNL November 5, 2013 Slide No. 16 LTHFSW13
Analysis of the Events
• Quench detection system determined the event a
quench as the voltage threshold was exceeded
• Quench protection system extracted the energy
rapidly
• All coils were re-tested a few times after the event
• No degradation in performance was found in coils
made with either SuperPower or ASC conductor
• This shows that the quench protection system can
protect the HTS coils against the events like this
Superconducting Magnet Division
Ramesh Gupta Medium and High Field HTS Magnet R&D at BNL November 5, 2013 Slide No. 17 LTHFSW13
High Field (>30T) Solenoid for MAP
b
a
ca) >12 T HTS solenoid (insert)
b) >10 T HTS (midsert)
c) >10 T LTS (outsert)
Promising demos with a series PBL/BNL SBIR (DOE/HEP)
Work continues under Muon Accelerator Program (MAP)
Superconducting Magnet Division
Ramesh Gupta Medium and High Field HTS Magnet R&D at BNL November 5, 2013 Slide No. 18 LTHFSW13
Initial Test of HTS Insert and Midsert and Preparation for High Field (>22 T) Test
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
0 2 4 6 8 10 12 14 16 18 20 22
Vo
ltag
e G
rad
ien
t (m
V/c
m)
Current (Amp)
Test of 100 mm HTS Solenoid (Each curve represents 12 coils)
• HTS Insert (14 pancakes, ran at 16 T peak field)
and Midsert (24 pancakes, 12 ran at 9 T peak)
• Expected on axis field at 4 K: > 22 T (design)
• All worked well during 77 K Pre-test
Superconducting Magnet Division
Ramesh Gupta Medium and High Field HTS Magnet R&D at BNL November 5, 2013 Slide No. 19 LTHFSW13
Test Results of Combined Structure (HTS Insert and HTS Midsert)
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26
Vo
ltag
e (m
V)
Current (A)
coil #1 coil #2
coil #3 coil #4
coil #5 coil #6
coil #7 coil #8
coil #9 coil #10
coil #11 coil #12
coil #13 coil #14
coil #15 coil #16
coil #17 coil #18
coil #19 coil #20
coil #21 coil #22
coil #23 coil #24
#15
#8
#11
#15
#8
#11
#16
Several pancakes got degraded during one @77 K test with LN2
• No further degradation seen after repeated test after this event
• Assumed cause: excessive thermo-mechanical strain during system testing
Superconducting Magnet Division
Ramesh Gupta Medium and High Field HTS Magnet R&D at BNL November 5, 2013 Slide No. 20 LTHFSW13
Repairing the Pancakes
-0.004
0.000
0.004
0.008
0.012
0.016
0.020
0 10 20 30 40
Vo
ltag
e (V
)
Current (A)
Coil 15 before repair
Coil 15 after repair
Became Good
Was Bad
Several (but not all) pancakes have been repaired by removing inner-
most turn and by making a new splice between the two single pancakes
Superconducting Magnet Division
Ramesh Gupta Medium and High Field HTS Magnet R&D at BNL November 5, 2013 Slide No. 21 LTHFSW13
Status and Moving Forward
• Repair as many HTS pancake coils as possible. Then rebuild the
magnet structure with either fewer pancakes (lower field) or with
replacement pancakes, depending on the funding (SuperPower has
kindly offered to contribute some conductor).
• Reduce the thermal strain on HTS coils with improved design (better
cooling with copper disks, etc.) and with slow controlled cooling.
• Retest the magnet to high fields to verify the analysis and the design.
• Future high field solenoid R&D at BNL relies on MAP (with all
SMES coils built and no similar high field program on the radar).
• We want to build upon the positives and lessons learnt and use
the existing coils, hardware and experience to complete the task.
• Modest support may produce significant results (remember: 16 T
HTS insert and 9 T half-midsert have already been tested once).
Superconducting Magnet Division
Ramesh Gupta Medium and High Field HTS Magnet R&D at BNL November 5, 2013 Slide No. 22 LTHFSW13
Feedback to
Conductor Manufacturer
Superconducting Magnet Division
Ramesh Gupta Medium and High Field HTS Magnet R&D at BNL November 5, 2013 Slide No. 23 LTHFSW13
Ic (77K, self field) and (4K, in-field)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
1 2 3 4 5 6 7 8
Ic(8T)/Ic(77K)
Ic(8T)/Ic(77K)
Courtesy: Arup Ghosh
0.0
0.5
1.0
1.5
2.0
2.5
0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0
Ic(H
)/Ic
(8T)
H, T
Series1
Series2
Series3
Series4
Series5
Series6
Series7
600700800900
100011001200130014001500
300 325 350 375 400 425 450
I C(8
T, F
ield
Pe
rp)
IC (77K, self field)
A factor of 2
variation in 4K
field perp Ic
Identical dependence of
(4K/77K) scaling as a function
of field (1 at 8T and 2 at 3T)
A large variation
in scaling ratio
• An opportunity to understand and
improve Ic significantly (2X or more)
• No variation in 4K scaling Vs Bperp.
• Means low field measurements are OK.
• Add curves at different temperatures.
• Make Ic Vs. T curves at different fields.
• Cheaper measurements improves stat.
See p
oste
r b
y A
rup
Gh
osh
3T
8T
2
1
Superconducting Magnet Division
Ramesh Gupta Medium and High Field HTS Magnet R&D at BNL November 5, 2013 Slide No. 24 LTHFSW13
More Wish-list on 2G Conductor
• One of the major strength of 2G HTS is its mechanical strength (high
modulus to deal with large Lorentz forces). However, current electro-
plating may be a weal link. Improve on it and add measurements of
various mechanical properties (including peel strength of copper), as
needed.
• Wider and/or multi-tape designs (for example like ASC supplied tape
for FRIB). It reduces inductances (good for quench protection) and
also the impact of weak-spots (a bit more forgiving).
• 2G cables – variety of types may be possible, each with its own
advantage for a given application.
Superconducting Magnet Division
Ramesh Gupta Medium and High Field HTS Magnet R&D at BNL November 5, 2013 Slide No. 25 LTHFSW13
Summary • HTS magnets offer unique solutions. There is no option but to use HTS to
build superconducting magnets operating either at very high fields or at very
high temperatures (cryo-free) or with large energy deposition (as in FRIB).
• We may be near the exciting period of “1968 Summer Study” in LTS
http://www.bnl.gov/magnets/staff/gupta/Summer1968/.
• We have several impressive results to indicate what HTS magnets can offer.
However, significant work remains to take advantage of their full potential.
• Initial test results of FRIB quad show that HTS may be able to handle quench
type events. However, more clear demonstrations are needed.
• Initial results of PBL/BNL high field HTS solenoid have been impressive
(particularly demonstration of 16 T insert and 9 T half midsert HTS solenoids
under the limited budget of SBIR).
• There is a potential to create ~25 T in HTS solenoid with modest funding, by
continuing the above program and coils. This would be a significant
contribution to the field with applications in many areas. With conventional
LTS outsert, we should be able to address a critical technology area for MAP.
http://www.bnl.gov/magnets/staff/gupta/Summer1968/http://www.bnl.gov/magnets/staff/gupta/Summer1968/http://www.bnl.gov/magnets/staff/gupta/Summer1968/http://www.bnl.gov/magnets/staff/gupta/Summer1968/Recommended