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Innovation with Integrity
Bruker Energy & Supercon Technologies (BEST) BRUKER HTS
RECENT DEVELOPMENTS OF COATED CONDUCTORS AT BRUKER
U. Betz, K. Schlenga, A. Usoskin, V. Selvamanickam
CCA 2016 Sep 13, Contribution ID: IO-15
This work was supported in part by the EC 7th Program, EUROTAPES project, Grant 280432 and EuCARD-2 project, CERN.
CCA 2016 #IO-15 BHTS All rights reserved PAGE 1
Innovation with Integrity
BRUKER HTS OUTLINE
(CUSTOMIZED INSULATION NOT SHOWN HERE)
Cu ENCAPSULATION
Ag CAP LAYER
YBCO LAYER
YSZ BUFFER LAYER
STAINLESS STEEL standard width 4 mm standard thickness 0.1 mm
Ø Deposition routes implemented
Ø Dynamic drum vs. reel-to-reel technology : comparison - tape travel speed/throughput - heat losses - reel diameter: physical limit
Ø High-field tapes: up-scaling of length
Ø 12 mm wide tapes for CERN
CCA 2016 #IO-15 BHTS All rights reserved PAGE 2
Innovation with Integrity 3
BRUKER HTS BHTS at the new site
Ø Successful relocation of the operation BHTS in Q3 2015
Ø Since August 2015: BHTS at the new site in the Röntgenstr. 9 in Alzenau
Ø More than 2000sqm operation area available
Ø Excellent infrastructure and media supply for vacuum coating fab lines
BRUKER HTS GmbH Industriepark Nord
Röntgenstr. 9 63755 Alzenau
Germany
CCA 2016 #IO-15 BHTS All rights reserved PAGE 3
Innovation with Integrity
Manufacturing Chain
CCA 2016 #IO-15 BHTS All rights reserved PAGE 4
Innovation with Integrity 5
BRUKER HTS Buffer layer coating (ABAD)
• Alternating Ion Beam Assisted Deposition ABAD
• ABAD vacuum coating equipment designed for long length production of coated conductors
• Both, drum batch processing and reel-to-reel processing equipment available
• Coating materials Y2O3, Al2O3, MgO and YSZ
CCA 2016 #IO-15 BHTS All rights reserved PAGE 5
Innovation with Integrity 6
BRUKER HTS YBCO layer coating (PLD)
• Pulsed Laser Deposition PLD vacuum coating equipment
• Drum batch processing concept
• Quasi-Equilibrium heating concept
• Industrial excimer laser providing stabilized UV power @ 308nm
CCA 2016 #IO-15 BHTS All rights reserved PAGE 6
Innovation with Integrity
Multi plume HR-PLD (MB PLD)
• Efficiency of material transfer is above 70%
• Pulse energy of 600 mJ is sufficient for 8 beams; thus further increase of throughput is possible
CCA 2016 #IO-15 BHTS All rights reserved PAGE 7
Innovation with Integrity
BRUKER HTS BHTS’s core competence
Ø Manufacturing of coated conductors (HTS 2G) tailored for it’s application in high magnetic fields
Ø Structural design of the YBCO superconducting thin films on a nano-scale by pulsed laser deposition PLD
EXTRINSIC second phase nano-structures
in the YBCO film
INTRINSIC stoichio-metric deviations in the YBCO film
CCA 2016 #IO-15 BHTS All rights reserved PAGE 8
Innovation with Integrity
Deposition route: Introduction of nano-periodic disorder/precipitation during PLD:
Quasi-equilibrium heater 1, 2, 5, 6 with
a substrate tape 3 helically wound on the cylindrical drum 4.
1
2
3
4
5
6
7
8
TABLE I AVERAGE PERIOD BETWEEN MAXIMA OF O2 PRESSURE PULSE
Parameter Model Experiment
thickness period 18.8 nm 14.5 nm
effective repetition rate of laser pulses
230 pulses/s 225 pulses/s
number of deposition pulses 18,800 17,900 time period 82 s 84 s
.
pressure triggered stoichiometry deviations (=“intrinsic” disorder/precipitations)
Tape translation: both a drum and reel-to reel routes are considered
CCA 2016 #IO-15 BHTS All rights reserved PAGE 9
Innovation with Integrity
Drum vs. RtR: limiting factors
a) throughput/travel speed of the tape
• In Reel-to-Reel (RtR) and drum cases: tape should travel with about 1 m/s speed. Slower motion leads to increase of local repetition rate of deposition pulsed which results in Ic deterioration
• In drum case, this travel is achieved via fast drum rotation
• In RtR case, the tape is permanently traveling between reels. Pre-heating of tape is needed therefore. Length of tape to be pre-heated is shown in figure for different heating temperatures and single/double side heating.
Length of tape to be pre-heated vs. temperature of IR heater in RtR route Addition heating power is estimated to 1.5 kW
CCA 2016 #IO-15 BHTS All rights reserved PAGE 10
Innovation with Integrity
Drum vs. RtR: limiting factors
b) drum concept (cont.)
• In drum case, tape quick travel is achieved via fast drum rotation
• Drum versus RtR translation:
• Limiting factor: tape throughput is limited by heat capacity of the drum
• “Dynamic” drum with reduced heat capacity and advanced mechanical stability is developed and employed in deposition of 600m long tapes.
• Dynamic drum enables tape throughput of > 60 m/hour
(a) (b)
Kinetics of tape + drum heating (a) and substrate temperature variation during PLD process (b) where drum rotates within a tubular IR heater with deposition window
980 1090 12001050
1055
1060
tim e, m s x 10
subs
trate
tem
pera
ture
, K
Time, s 0 1.1 1.2
1.060
1.050 200 0 100 200 300200
400
600
800
1000
1200
time, s
tem
pera
ture
, K
Ti 1....c ρ t
..ε σo 10 4
1 Th100
4 Ti100
4
dτ Ti
Time, s 0 100 300
1.2
1.0
Sub
stra
te te
mpe
ratu
re, a
.u.
0.8
0.6
0.4
0.2
Sub
stra
te te
mpe
ratu
re, a
.u.
1.055
200
CCA 2016 #IO-15 BHTS All rights reserved PAGE 11
Innovation with Integrity
Drum vs. RtR: limiting factors
c) reel diameter is limited by cumulative normal pressure coming from tape windings
• Damage threshold by winding on reel with 300mm core diameter is estimated to 1000 m length
Ft
Fn
(=T)
Tape length, m
Nor
mal
pre
ssur
e, M
Pa
(a)
(b)
CCA 2016 #IO-15 BHTS All rights reserved PAGE 12
Innovation with Integrity
Drum vs. RtR: summary
Drum Reel-to-Reel
• Tape translation drum rotation multiple tape instead of travel needed multiple travel (typically >20 cycles)
• Tape throughput > 60 m/hour >60 m/hour with “dynamic” drum
• Tape length > 600 m 1000 m with “dynamic” drum limited by 1000m to be validated cumulative pressure
• Additional heating power no 50%, additional
impurity source
• Both concepts undergo further feasibility and applicability analyses
CCA 2016 #IO-15 BHTS All rights reserved PAGE 13
Innovation with Integrity
Up-scaling to piece length above 600 m:
223 m and 610 m long tape after deposition of HTS layer
CCA 2016 #IO-15 BHTS All rights reserved PAGE 14
Innovation with Integrity
BRUKER HTS
For the standard configuration:
• L > 500m single piece length • Ic > 1500A/cm at 4.2K 5T Bllc • Ic std. dev. of +/-2.5% at 77K • σc: 650MPA critical tensile stress
• Long length 2G HTS single wires with high in-field Ic performances at 4.2K
YBCO thin films coating by pulsed laser deposition PLD
CCA 2016 #IO-15 BHTS All rights reserved PAGE 15
Innovation with Integrity
Ic per cm-width versus piece length (at 4.2 K,18T, B//c)
• Highest critical currents correspond to 1250 A/cm-width in 22 m batch. HTS film thickness is always between 1.5 and 1.7 µm in tapes longer than 100m. In 22 m long tape the HTS thickness is ~2 µm.
In 2016, HTS tapes were upgraded to 600m WITHOUT REDUCTION of Ic
2015 2016
CCA 2016 #IO-15 BHTS All rights reserved PAGE 16
Innovation with Integrity
Comparison Ic(4K; B) in 4mm tapes : FSU + BHTS updated
B, T
1-905N3 1-905N4
309 A at 31 T
CCA 2016 #IO-15 BHTS All rights reserved PAGE 17
Innovation with Integrity
Ic homogeneity: TapeStar
Major recent achievements: the transfer of high Ic in-field performances on long single piece tape lengths
Example
Ø 4 mm wide and 550 m long HTS tape with I @ 4.2 K/5 T well above 700 A measured on samples from both tape ends
Ø Enhanced Ic uniformity measured with Hall-probe measurements at 77 K (Tapestar)
0 50 100 150 200 250 300 350 400 450 500 550 600 Tape length, m
0
20
40
80
60
Crit
ical
cur
rent
at 7
7K,
A 100
CCA 2016 #IO-15 BHTS All rights reserved PAGE 18
Innovation with Integrity
Ic homogeneity: FFT analysis
580 m long tape, interval analyzed: from 175 to 221 m
Expanded low frequency range
CCA 2016 #IO-15 BHTS All rights reserved PAGE 19
Innovation with Integrity
12mm wide tapes for EUCARD2 CERN
BHTS manufactured several 12mm wide tapes for EUCARD2, CERN
The high field performance (18T) was confirmed: - minimum Je of 400 A/mm2 @ 4.2K/18T is required for the C12 tapes, - most tapes are far above this spec (in spite of thick substrate tape)
Ic=1086 A/cm-w
CCA 2016 #IO-15 BHTS All rights reserved PAGE 20
Innovation with Integrity
Highlight Summary
• “Dynamic” drum and reel-to-reel concepts are compared and analyzed. Advantages of both systems will be used in further development. Presently PLD machines are based on “dynamic” drum.
• Based on ABAD and PLD with double disordered HTS layers Bruker confirmed reproducibility of very high critical currents in high field and 4.2 K
• Technology was scaled up from 200m to 600m tape length with no considerable change of critical current. Accessible range of critical currents: 600-800 A/cm-width at 18 T, Bǁ‖c, 4.2 K.
• Processing of 12 mm wide tapes with high Ic and Je is in pilot production status. Most number of tapes yields Ic > 900 A/cm-width at 18 T, 4.2 K, Bǁc
CCA 2016 #IO-15 BHTS All rights reserved PAGE 21
Innovation with Integrity 22
www.bruker-HTS.com
Bruker Confidential
All rights reserved PAGE 22
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