Post on 25-Jun-2020
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 1 ISS2012
Very High Field HTS and
Superconducting Magnets
Ramesh Gupta
Brookhaven National Laboratory (BNL), USA (for BNL staff and collaborators from PBL and SMES Team)
25th International Symposium on Superconductivity, Tokyo, Japan
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 2 ISS2012
Overview
• HTS in High Field Superconducting Magnets
– Opportunities and Challenges
• HTS Magnet Programs at BNL
– We work on a variety of magnet types (solenoid, dipoles, etc.).
The focus of this presentation is on very high field solenoids.
– A15+ T HTS solenoid already designed, built and tested; and
a more ambitious 20-25 T goal in 2013 in multiple programs
– Ultimate target: ~40 T in a hybrid design (HTS+LTS)
• Summary
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 3 ISS2012
Modern Superconductors for Very High Field Magnets
Court
esy:
P. Lee,
NH
MF
L
HTS offer unique
opportunities
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 4 ISS2012
High Field Superconductor (HTS)
• The development of High Temperature Superconductor (HTS) as
the High Field Superconductor (HFS) is the key to all ongoing
very high field magnet development programs
• High strength HTS (e.g., with Hastelloy substrate from
SuperPower) are very attractive for high field applications
• Progress in conductor to date has been impressive. There is even
more room for progress – even higher Ic and more uniform Ic
• But conductor is only the beginning. There are several
challenges in making very high field magnets out of them
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 5 ISS2012
Challenges with HTS for High Field Superconducting Magnets
• Anisotropic electrical properties for YBCO or tape conductor
• Mechanical properties (more so for 2212 but for YBCO also)
• Quench protection : a major issue for HTS
• Containment (mechanical) structure
• Conductor cost
More discussion later with progress made in some of these areas
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 6 ISS2012
HTS Magnet Programs at BNL
• Brookhaven National Laboratory (BNL) has been active in HTS conductor, coil
and magnet R&D for over a decade. The level of effort has been significant:
– Received over 50, 000 meters of HTS (normalized to 4 mm tape)
– Built well over hundred coils and a large number of magnets
– Used all – Bi2212, Bi2223, YBCO, MgB2 - in round wire and tape form
• Magnet R&D on a wide range of programs:
– Low field, high temperature (unique and sometime cost-effective)
– Medium field, medium temperature (baseline design of a major machine)
– High Field, low temperature focus of this presentation
These variety of programs help develop a wider understanding and cross solutions
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 7 ISS2012
High Field Solenoid Programs
• Ongoing programs:
~25 T High Energy Density SMES
~40 T Solenoid for Muon Accelerator Program
• Other future possibilities:
NMR
???
???
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 8 ISS2012
Motivation for High Field HTS SMES
High Temperature (~65 K) Option: Saves on cryogenics (Field ~2.5 T)
High Field (~25 T) Option: Saves on Conductor (Temperature ~4 K) High Temperature
High Field
Some previous/other work:
LTS: ~5 T (~4 K operation)
HTS: few to several Tesla (20 K or more)
Our analysis on HTS option:
Conductor cost dominates the cryogenic
cost by an order of magnitude
An aggressive option:
Ultra high fields ~25 T
Only possible with HTS
High risk and high reward program Partnership between BNL,
SuperPower and ABB
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 9 ISS2012
Concept of GRID Scale (GJ scale) Superconducting Energy Storage
Participants: ABB (Lead), SuperPower/Furukawa and BNL
Funded by arpa-e as a “high risk, high reward” project.
Concept of a single Unit Concept of Number of units in a toroidal SMES system
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 10 ISS2012
High Field Solenoid for Proposed Muon Collider
Muon collider:
• An exciting and challenging machine
One key challenge:
• High field (~40 T) solenoid for cooling
Resistive magnet would use enormous
electro power (hundreds of MW)
Even a combination of resistive and
superconductive magnets will consume
large power
Need superconducting magnets and
use of HTS for such high field is essential Courtesy: Bob Palmer
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 11 ISS2012
Modern Superconductors for Very High Field Magnets
Court
esy:
P. Lee,
NH
MF
L
• Hybrid design offers a
more affordable solutions
• Use HTS in higher field
region and LTS in lower
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 12 ISS2012
30-40 T Technology Demo Magnet
Design consisted of several coils (HTS and LTS)
1. 10-15 T HTS insert coil (~25 mm aperture)
2. 10-12 T HTS midsert coil (~100 mm aperture)
3. 6-15 T LTS coil(s) - NbTi for 6-8 T; and/or Nb3Sn for 12-15 T
1
2
3
20-25 T All HTS Coils (1 & 2):
addresses challenges with high
field HTS solenoids
30-40 T All Superconducting
Solenoid (1, 2 and 3+):
addresses challenges with high
field superconducting solenoids
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 13 ISS2012
Funding Status of 30-40 T Solenoid
This technology is being primarily developed under a series of US
DOE SBIR (Small Business Innovative Research Program) with
BNL (a national lab) collaborating with PBL, Inc. (an industry.)
Funding Status:
1. HTS insert solenoid : Funded
2. HTS midsert solenoid : Funded
3. LTS outsert : Not yet funded for construction
Courtesy: Bob Palmer
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 14 ISS2012
PBL/BNL High Field HTS Solenoids
10+ T,100 mm
HTS solenoid
(midsert) with 24
pancakes for full
length solenoid
(ready for test)
15+ T, 25 mm HTS
solenoid (insert)
with 14 pancakes
already tested
Half length 100 mm
with 12 pancakes
already tested and
reached 6+ T on
axis (9+ T peak)
Use of high strength HTS is critical to the success
Coils made with
~4mm HTS tape
from SuperPower
Record
Field
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 15 ISS2012
High Field HTS Solenoid Test Results (magnet #1 using SuperPower HTS)
Field on axis:
over 15 T
Field on coil:
over 16 T
(original target was 10-12 T)
Real demo of 2G HTS to
create high field
Highest field ever in
an all HTS solenoid
Overall Jo in coil:
>500 A/mm2 at 16 T
(despite anisotropy)
14 pancake coils with ~25 mm aperture
Note: Benefit of HTS – large operating range
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 16 ISS2012
Test Results of HTS Solenoid #2 (½ Midsert, 12 coils instead of 24)
0
25
50
75
100
125
150
175
200
225
250
275
300
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80
Cu
rre
nt
(A)
Temp(K)
Peak Field on Coil at 250 A : ~9.2 T
Coil operated with margin at 250 A
PBL/BNL 100 mm HTS Solenoid Test for Muon Collider
Large use (1.2 km) of 2G
HTS in high field magnet.
250 A ==>
6.4 T on axis
9.2 T peak
field on coil
SuperPower HTS
Coil could have reached above 10 T peak (original target),
but was not ramped up to protect electronics of that time.
Full solenoid with 24 pancakes should create >10 T on axis.
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 17 ISS2012
Status of High Field MAP Solenoids
1
2
3
Two HTS coils together made with SuperPower
HTS is expected to create 20-25 T, if successful
~30 T with NbTi outer
(40 T with Nb3Sn or more HTS)
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 18 ISS2012
Challenges with High Field HTS Magnet Technology
Discussion on two selected topics:
• Quench Protection
– Slow quench propagation velocities
– Coil may get degraded even before one detects quench
• Mechanical Properties
– Stress /strain tolerance important in high field magnets
– Asymmetric properties of tape (just as magnetic)
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 19 ISS2012
High Current Test of 4 mm Tapes
0
50
100
150
200
250
300
350
400
450
500
550
600
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90
I c, A
(0
.1 m
V/c
m)
Temp (K)
ASC YBCO Coil (with nano-dots)
SP YBCO Coil (without doping)
ASC BSCCO Coil (1st series)
ASC YBCO Coil
ASC Bi2223
SP YBCO Coil
During the initial R&D period, coils with 2G HTS tape from ASC (~0.4 mm
X 0.3 mm) and SuperPower (0.4 mm X 0.1 mm) were built and tested
Coil built with 4mm tape
purchased ~5 years ago
Max current: 540 A and 580 A; coils remain protected
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 20 ISS2012
Low Temp Performance of FRIB Coils (R&D during technology development period)
ASC YBCO Coil (with nano-dots)
SP YBCO Coil (without doping)
ASC BSCCO Coil (1st series)
0
100
200
300400
500
600
700
800
900
10001100
1200
1300
1400
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90
Temp (K)
Je,
A/m
m2 (
0.1
mV
/cm
)
ASC YBCO Coil
ASC Bi2223 Coil
SP
YBCO
Coil
These numbers are amazing ...
• May be too demanding for protection and should be avoided in real applications.
Tape width: ~ 4 mm; Length used in single coil ~100 meter
Copper thickness: SuperPower ~ 0.045 mm; ASC ~ 0.1 mm
If coils go normal (momentarily
or thermal runaway, etc.).
• Copper current density in ASC
coil : ~1500 A/mm2
• Copper current density in
SuperPower coil : ~3000 A/mm2
Coil remained protected
(we usually don’t allow such
high Jcu in LTS magnets)
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 21 ISS2012
0
200
400
600
800
1000
1200
1400
70 74 78 82 86
Vo
lta
ge
(m
V)
Current (A)
BNL Quench Protection Strategy
• Quench protection in high field HTS magnets is one of the biggest challenges of the field.
• We have developed a unique approach to overcome this challenge.
• Use problem (things happening slowly) to our advantage.
• Detect the longer pre-quench phase of HTS (where coil can be operated safely) and initiate the action for protection.
• This requires detecting small resistive voltage in presence of large noise and inductive voltages – challenge in large systems.
• BNL has made significant advances in electronics to detect start of this pre-quench phase well below 1 mV rather than 50-100 mV.
Pre-quench phase
Use quench protection heaters
as the final line of defense
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 22 ISS2012
Advanced Quench Detection System Developed at BNL
• Advance quench protection
electronics detects quench fast and
extract energy quickly.
• This requires development of low
noise, fast electronics with large
isolation voltage.
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 23 ISS2012
Mechanical Properties of HTS
• HTS tapes (such as 2G tape with Hastelloy substrate)
have inherently higher stress and strain tolerances and
are particularly suitable for high field solenoids
• However, even these 2G tape have relatively lower
stress tolerance on the narrower face (question how
much). Question is how much?
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 24 ISS2012
Mechanical Properties of High Strength HTS from SuperPower
High Strength HTS are
important for high field magnets
High Strength HTS from SuperPower/
Furukawa tested at Florida, USA
But what happens on the narrow face?
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 25 ISS2012
Measurements to Study the Influence of Stress on the Narrow side of HTS Tape
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 26 ISS2012
Bi-filar Coil for Axial Loading
Load is applied on the
narrow face.
Bi-filar winding is
chosen to minimize
the influence of
magnetic field on Ic.
Maximum load
applied: 107 MPa
(max in current
designs ~100 MPa)
The test was carried
out in real situation:
the coil remain cold
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 27 ISS2012
Voltage versus pressure cycle (0 to 4200psi / 107MPa)
0.00
50.00
100.00
150.00
200.00
250.00
300.00
1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106 113 120 127 134 141
# of cycles
vo
ltag
e (
uV
)
sec1
sec2
sec3
sec4
sec5
sec6
Influence of ~107 MPa Pressure on the Narrow Face of Conductor in 2G HTS Coil
Signal in the inner section due to 107 MPa axial load
0
0.5
1
1.5
2
2.5
3
3.5
1 10 19 28 37 46 55 64 73 82 91 100 109 118 127 136
cycles
mV
/cm
inner1
inner2
Signal in the middle section due to 107 MPa axial load
0
0.5
1
1.5
2
2.5
3
3.5
1 10 19 28 37 46 55 64 73 82 91 100 109 118 127 136
cycles
mV
/cm
middle1
middle2
Signal in the outer section due to 107 MPa axial load
0
0.5
1
1.5
2
2.5
3
3.5
1 10 19 28 37 46 55 64 73 82 91 100 109 118 127 136
cycles
mV
/cm
outer1
outer2
Load ON, Load OFF. Measure change in
voltage in ~100 cm (1 m) long six sections
~0.5% reversible change in Ic
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 28 ISS2012
Other High Field Geometries
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 29 ISS2012
• High field (>20 T) cosine theta magnet technology with
complex ends
• The proposed energy and luminosity upgrade of LHC at
CERN will require high field dipole and quadrupole magnets
• Hybrid designs with HTS inner
Dipole NbTi Magnet (BNL)
Quadrupole Nb3Sn Magnet
( Courtesy: Bill Sampson, BNL)
Cosine theta prototype magnets built and tested in BNL using LTS materials
Courtesy: S. Lakshmi
HTS Dipole and Quadrupole
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 30 ISS2012
V4
V5
V6
V11
V10
V9
Inner most turn
(straight sections)
Innermost turn
(straight sections)
Outer most turn
(straight sections)
Inner to outer turn
and Outer turn
Courtesy: S. Lakshmi
Several V-taps for Detailed Examinations
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 31 ISS2012
Conductor length :14 m
Dipole coil: I-V test at 77 K; self field
Y axis represents the end-to end voltage in the coil
block (V1-V16)
Based on
1mV/cm criterion: Ic= 204 A
0.1mV/cm criterion: Ic= 187.8 A
Courtesy: S. Lakshmi
Test Results at 77 K
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 32 ISS2012
Other Significant HTS Magnet
Development at Medium Fields
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 33 ISS2012
Magnets for the Fragment Separator of Facility of Rare Isotope Beams
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
Large Radiation and Heat Loads in Fragment Separator Region Magnets
Radiation resistant
Copper or NbTi Magnets don’t satisfy the requirements
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 34 ISS2012
HTS Magnets For FRIB
• HTS offers a unique solution for challenging environment of
FRIB magnets with unprecedented energy and radiation loads.
• Because of large thermal margins HTS magnets can operate
reliably and can remove large heat loads efficiently at ~40 K.
HTS magnets are now the baseline design for the quadrupole
and dipole magnets in the fragment separator region of FRIB.
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 35 ISS2012
SuperPower ASC
FRIB HTS Quadrupole
220 mm, >15 T/m
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 36 ISS2012
Coils in FRIB Quad Structure @77 K (made with 2G HTS from SuperPower and ASC)
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
0.2
0 10 20 30 40 50 60 70 80 90
Volt
ag
e G
rad
ien
t (m
V/c
m)
Current (A)
Performance normalized to per tape (ASC has double)
SP Coil 1
SP Coil 2
SP Coil 3
SP Coil 4
ASC Coil 1
ASC Coil 2
ASC Coil 3
ASC Coil 4
internal splice
Ic defined at 0.1 mV/cm
~330 meter
12 mm used
in each of four
SuperPower
coil and
~215 meter
12mm double
tape used in
each of four
ASC coil
Performance
at ~40 K is
more relevant
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 37 ISS2012
Summary
• High field all HTS solenoids can now be successfully built using a
significant amount of conductor (~2 km)
• Maximum field on coil >16 T, overall current density (Jo) in coil
>500 A/mm2 – new record for the technology
• We still have a lot to demonstrate and many challenges to overcome
• However, the impact of these two results of all HTS solenoid (and
other high field insert coil test at NHMFL) is obvious
• We are now at the verge of revolutionizing the superconducting
magnet technology – reaching higher field as never possible before
• Stay tuned for more results in coming years from around the world.
We hope that 30-40 T solenoids will become a reality.
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 38 ISS2012
Back-up Slides
Superconducting Magnet Division
Ramesh Gupta, BNL, USA Very High Field HTS Magnets Tokyo, Japan Slide No. 39 ISS2012
Original Design Parameters (as presented at ASC2010)
Target Design field (optimistic) ~22 T
Number of coils (radial segmentation) 2 self supporting
Stored Energy (both coils) ~110 kJ
Inductance (both in series) 4.6 Henry
Nominal Design Current ~220 A
Insulation (Kapton or stainless steel) ~0.025 mm
Je (engineering current density in coil) ~390 A/mm2
Conductor
Width
Thickness Stablizer
2G ReBCO/YBCO
~4 mm
~0.1 mm ~0.04 mm Cu
Outer Solenoid Parameter
Inner diameter Outer diameter
Length
Number of turns per pancake Number of Pancakes
Total conductor used
Target field generated by itself
~100 mm ~160 mm
~128 mm
~240 (nominal) 28 (14 double)
2.8 km
~10 T
Inner Solenoid Parameter
Inner diameter
Outer diameter Length
Number of turns per pancake
Number of Pancakes
Total conductor used
Target field generated by itself
~25 mm
~90 mm ~64 mm
~260 (nominal)
14 (7 double)
0.7 km
~12 T
External Radial support (overband) Stainless steel tape
Target Design field (optimistic) ~22 T
Number of coils (radial segmentation) 2 self supporting
Stored Energy (both coils) ~110 kJ
Inductance (both in series) 4.6 Henry
Nominal Design Current ~220 A
Insulation (Kapton or stainless steel) ~0.025 mm
Je (engineering current density in coil) ~390 A/mm2
Conductor
Width
Thickness Stablizer
2G ReBCO/YBCO
~4 mm
~0.1 mm ~0.04 mm Cu
Outer Solenoid Parameter
Inner diameter Outer diameter
Length
Number of turns per pancake Number of Pancakes
Total conductor used
Target field generated by itself
~100 mm ~160 mm
~128 mm
~240 (nominal) 28 (14 double)
2.8 km
~10 T
Inner Solenoid Parameter
Inner diameter
Outer diameter Length
Number of turns per pancake
Number of Pancakes
Total conductor used
Target field generated by itself
~25 mm
~90 mm ~64 mm
~260 (nominal)
14 (7 double)
0.7 km
~12 T
External Radial support (overband) Stainless steel tape
This was thought to be a very ambitious proposal!!!
We have achieved >60% (6+ T) with only half outer
We have already exceeded inner by over 25% (15+ T)
24 (12)
Midsert