bi-2212 / nb 3 sn hybrid dipole for ~20 t lhc energy upgrade kyle damborsky, feng lu, al mcinturff,...
DESCRIPTION
j E in Bi-2212 strand tripled in , but… We need 800 A/mm 2 but haveTRANSCRIPT
![Page 1: Bi-2212 / Nb 3 Sn hybrid dipole for ~20 T LHC Energy Upgrade Kyle Damborsky, Feng Lu, Al McInturff, Peter McIntyre, Akhdiyor Sattarov, Elizabeth Sooby](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1b287f8b9ab0599981d7/html5/thumbnails/1.jpg)
Bi-2212 / Nb3Sn hybrid dipole for ~20 T LHC Energy Upgrade
Kyle Damborsky, Feng Lu, Al McInturff, Peter McIntyre, Akhdiyor Sattarov , Elizabeth Sooby
![Page 2: Bi-2212 / Nb 3 Sn hybrid dipole for ~20 T LHC Energy Upgrade Kyle Damborsky, Feng Lu, Al McInturff, Peter McIntyre, Akhdiyor Sattarov, Elizabeth Sooby](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1b287f8b9ab0599981d7/html5/thumbnails/2.jpg)
In 1996 I presented a conceptual design for a 24 T dipole for an LHC Tripler
Dual dipole (ala LHC)Bore field 24 TeslaMax stress in superconductor 130 MPaSuperconductor x-section:
Nb3Sn 26 cm2
Bi-2212 47 cm2
Cable current 25 kABeam tube dia. 50 mmBeam separation 194 mm
Several problems:The design used Bi-2212 Rutherford cable – how to control Lorentz stress in inner winding?How to separately react Bi-2212 in oxygen, Nb3Sn in argon?The design assumed je =800 A/mm2 in Bi-2212 strands. We are still < 400 today!
![Page 3: Bi-2212 / Nb 3 Sn hybrid dipole for ~20 T LHC Energy Upgrade Kyle Damborsky, Feng Lu, Al McInturff, Peter McIntyre, Akhdiyor Sattarov, Elizabeth Sooby](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1b287f8b9ab0599981d7/html5/thumbnails/3.jpg)
jE in Bi-2212 strand tripled in 2001-2006, but… We need 800 A/mm2 but have <400.
Not much improvement in je since 2006.And performance is still ~ 1/L!
Applied Field (T)
0 5 10 15 20 25 30 35 40 45
J E (A
/mm
2 )
10
100
1000
2212 prototype wireNb3Sn - RRP
Nb3Sn - bronze
NbTi commercial wireMgB2 monocore wireYBCO sample (Bperp)
Tripler
![Page 4: Bi-2212 / Nb 3 Sn hybrid dipole for ~20 T LHC Energy Upgrade Kyle Damborsky, Feng Lu, Al McInturff, Peter McIntyre, Akhdiyor Sattarov, Elizabeth Sooby](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1b287f8b9ab0599981d7/html5/thumbnails/4.jpg)
See if we can devise a way to cure the ills of OPIT.
Current transport in OPIT Bi-2212/Ag strand is limited by high-angle brain boundaries, porosity, parasitic phases
Bi2212 Jc limitation
High Angle Grain Boundary (HAGB)
Defects- Pores- Impurities- Cracks
We might go far to eliminate all of these problems if we could fully texture the powder in the subelements:
But how to do it?
![Page 5: Bi-2212 / Nb 3 Sn hybrid dipole for ~20 T LHC Energy Upgrade Kyle Damborsky, Feng Lu, Al McInturff, Peter McIntyre, Akhdiyor Sattarov, Elizabeth Sooby](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1b287f8b9ab0599981d7/html5/thumbnails/5.jpg)
OST 2212 filaments – Longitudinal SEM of etched subelements Dwire ≈ 1.04 mm
Dfilament ≈ 20 μm
Uniform
Well separated
No sausaging
T. Shen thesis
OST 85 x 7 filaments
20
um
![Page 6: Bi-2212 / Nb 3 Sn hybrid dipole for ~20 T LHC Energy Upgrade Kyle Damborsky, Feng Lu, Al McInturff, Peter McIntyre, Akhdiyor Sattarov, Elizabeth Sooby](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1b287f8b9ab0599981d7/html5/thumbnails/6.jpg)
6
Commercial high Jc Bi-2212/Ag wires show many HAGB
Green State
10 μm
Fully Processed
• Lots of misaligned grains – HAGBs
• Jc(4.2 K) much lower than fundamental limit
• Clear sign of much great performance
– One path is to improve grain alignment (texture)
Wires from Oxford Superconducting Technology
Imaged by F. Kametani
![Page 7: Bi-2212 / Nb 3 Sn hybrid dipole for ~20 T LHC Energy Upgrade Kyle Damborsky, Feng Lu, Al McInturff, Peter McIntyre, Akhdiyor Sattarov, Elizabeth Sooby](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1b287f8b9ab0599981d7/html5/thumbnails/7.jpg)
7
Texture is evaluated using SEM and XRD• Microstructure by Scanning Electron Microscopy (SEM)
2212 is micaceous, growing preferentially in the ab plane C-axis is normal to large, flat 2212 surfaces
• Orientation by X-ray Diffraction (XRD) (00L) family of peaks correspond to c-axis orientation Texture parameter to semi-quantify texture
τ = I(0010)Scaled/(I(0010)Scaled + I(115))
where I(0010)Scaled = I(0010) –ε*I(115)
ε = I(0010)/I(115) =0.25 (from PDF-2 data)
giving:Random orientation: τ ≈ 0
Fully textured: τ = 1
![Page 8: Bi-2212 / Nb 3 Sn hybrid dipole for ~20 T LHC Energy Upgrade Kyle Damborsky, Feng Lu, Al McInturff, Peter McIntyre, Akhdiyor Sattarov, Elizabeth Sooby](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1b287f8b9ab0599981d7/html5/thumbnails/8.jpg)
20 30 40 50A
g(20
0)
Transversal Scan
Inte
nsity
(a.u
.)
2 (degree)
Longitudinal Scan
OST Green Wire
Ag(
111)
OST 2212 filaments - XRD
2212
Both longitudinal and transversal scan show strong 2212 peaks.
0 1 2 3 4 5 6 7 8 9 100.0
0.2
0.4
0.6
0.8
1.0
Frac
tion
of to
tal d
iffra
cted
inte
nsity
, G(X
)
Effective depth of CuK X-ray penetration, X (m)
Bi2212 (115, 27.361o) Bi2212 (0010, 28.919o) Bi2212 (200, 33.040o)
G(X) = 1-e-2X/sin
=linear absorption coefficient, cm-1
= mass absorption coefficient x density = 153.66 cm2/g x 6.52 g/cm3
X = effective depth of x-ray penetration = Bragg angle2X/ = effective path length of x-ary for X at
Cu K X-ray penetration depth on 2212 is ~ 5-6 m.
![Page 9: Bi-2212 / Nb 3 Sn hybrid dipole for ~20 T LHC Energy Upgrade Kyle Damborsky, Feng Lu, Al McInturff, Peter McIntyre, Akhdiyor Sattarov, Elizabeth Sooby](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1b287f8b9ab0599981d7/html5/thumbnails/9.jpg)
• No obvious texture, only slightly better than loose powder• Detectable 2201
(008
)
(001
0)(113
)
(115
)
(117
)
(119
)
(200
)Texture Parameter
0.37
0.31
0.27
OST 2212 filaments – XRD, cont
![Page 10: Bi-2212 / Nb 3 Sn hybrid dipole for ~20 T LHC Energy Upgrade Kyle Damborsky, Feng Lu, Al McInturff, Peter McIntyre, Akhdiyor Sattarov, Elizabeth Sooby](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1b287f8b9ab0599981d7/html5/thumbnails/10.jpg)
10
The simplest way to texture a micaceous powder: press a tablet:
Press
Anvil
Pellet
Die Set
Force
Press
Anvil
Pellet
Die Set
Force
• Precursor Powder Praxair Bi2212 powder, non-agglomerated
• Powder Pellet Uniaxial pressing up to 60 kpsi 1 – 1.2 mm thick
• Texture analysis Surface and bulk
![Page 11: Bi-2212 / Nb 3 Sn hybrid dipole for ~20 T LHC Energy Upgrade Kyle Damborsky, Feng Lu, Al McInturff, Peter McIntyre, Akhdiyor Sattarov, Elizabeth Sooby](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1b287f8b9ab0599981d7/html5/thumbnails/11.jpg)
11
Almost all grains are aligned along c-axis Uniform powder layer Orientated micaceous grains ~ 5-10 μm Better connectivity and texture with higher pressure
20 kpsi
100μm
10μm
100 μm
10 μm 10μm
100μm
60 kpsi100 μm
10 μm
![Page 12: Bi-2212 / Nb 3 Sn hybrid dipole for ~20 T LHC Energy Upgrade Kyle Damborsky, Feng Lu, Al McInturff, Peter McIntyre, Akhdiyor Sattarov, Elizabeth Sooby](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1b287f8b9ab0599981d7/html5/thumbnails/12.jpg)
12
Texture is highly enhanced by pressing Intensity of (00L) peaks dramatically increased Texture parameter 4 times higher Texture parameter increases with increasing pressure
20 25 30 35
20_kpsi_11mm_sideB
2 (degree)
Inte
nsity
20_kpsi_11mm_sideA
SSC Powder
(008
)
(113
)
(115
)
(001
0)(1
17)
(200
)
![Page 13: Bi-2212 / Nb 3 Sn hybrid dipole for ~20 T LHC Energy Upgrade Kyle Damborsky, Feng Lu, Al McInturff, Peter McIntyre, Akhdiyor Sattarov, Elizabeth Sooby](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1b287f8b9ab0599981d7/html5/thumbnails/13.jpg)
13
Texture is homogeneous through bulk and reproducible sample-sample
Surface and fracture have similar texture parameter Polish may re-texture powder The process and result can reproduce well
20 kPsi, 11 mm dia., ~1 mm thick pellets
Sample #1#2 #3
![Page 14: Bi-2212 / Nb 3 Sn hybrid dipole for ~20 T LHC Energy Upgrade Kyle Damborsky, Feng Lu, Al McInturff, Peter McIntyre, Akhdiyor Sattarov, Elizabeth Sooby](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1b287f8b9ab0599981d7/html5/thumbnails/14.jpg)
We are developing a process to make continuous ribbons of compressed Bi-2212 fine powder
Goals:jelly-roll conductor with fully textured Bi-2212 coresHeat treatment using solid-phase diffusion or partial meltObjective: je >800 A/mm2
50 mm dia. billet, 0.5 mm roll pitch
Draw billet to ~1 mm final dia., 10 µm roll pitchWe expect textured micaceous powder to draw well – remember mica paper!
![Page 15: Bi-2212 / Nb 3 Sn hybrid dipole for ~20 T LHC Energy Upgrade Kyle Damborsky, Feng Lu, Al McInturff, Peter McIntyre, Akhdiyor Sattarov, Elizabeth Sooby](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1b287f8b9ab0599981d7/html5/thumbnails/15.jpg)
Structured cable of Bi-2212 round strands
Manage stress within cable,Provide a conduit for oxygen flow during heat treatmentProvide a conduit for cryogen to refrigerate throughout the coil
100 MPaDeveloped 2002Cable current equals sum of strand Iss :No degradation from cabling, winding, heat treat in armor sheath
But we need >15 kA cable current for dipole.
![Page 16: Bi-2212 / Nb 3 Sn hybrid dipole for ~20 T LHC Energy Upgrade Kyle Damborsky, Feng Lu, Al McInturff, Peter McIntyre, Akhdiyor Sattarov, Elizabeth Sooby](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1b287f8b9ab0599981d7/html5/thumbnails/16.jpg)
16-strand structured cable
6 mm
Add another layer of strands in cable.The 3 spring tubes provide stress management along every touch axis in the cable.Makes 18 kA cable, winds to a reasonable winding in hybrid coil.
2 cm
6 cm
![Page 17: Bi-2212 / Nb 3 Sn hybrid dipole for ~20 T LHC Energy Upgrade Kyle Damborsky, Feng Lu, Al McInturff, Peter McIntyre, Akhdiyor Sattarov, Elizabeth Sooby](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1b287f8b9ab0599981d7/html5/thumbnails/17.jpg)
So what could this give us for a dipole?
Bore field (90% short sample)18 TBore tube 60 (h) x 50 (v) mmCoil current 10 kAStored energy 2.64 MJ/boreMax stress in Nb3Sn <150 MPa
Inner Nb3Sn Outer Nb3Sn Bi-2212/Agstrand dia. 0.87 0.65 1.0 mm# strands in cable 22 30 16# turns in windings: top layer 8x2 21x2 3x5
bottom layer 8x2 22x2 3x5
![Page 18: Bi-2212 / Nb 3 Sn hybrid dipole for ~20 T LHC Energy Upgrade Kyle Damborsky, Feng Lu, Al McInturff, Peter McIntyre, Akhdiyor Sattarov, Elizabeth Sooby](https://reader035.vdocuments.us/reader035/viewer/2022062317/5a4d1b287f8b9ab0599981d7/html5/thumbnails/18.jpg)
Conclusions• We have gone back to basics to try to develop a textured-powder JR
strand for Bi-2212– Eliminate HAGBs– Reduce porosity– We hope to achieve optimum connectivity without full melt, thereby knocking out
parasitic phases
• We have evolved our Bi-2212 structured cable to add another layer and push up cable current– Maintain stress management using a triplet of spring tubes– Manifold O2 flow during heat treats– Manifold cryogen flow during operation
• We have simplified the winding structure while keeping within bounds for stress in both Bi-2212 and Nb3Sn windings
Please critique this strategy as we prepare to do serious work!