Progress on MgB2 at CERNA. Ballarino, CERN

A. Ballarino, B. Bordini, S. Giannelli, J. Hurte, A. Jacquemod and L. Rossi

April 9th, 2014

-Electrical transmission: powering of superconducting magnet circuits via remote distance

The project: Hi-Luminosity upgrade of LHCPowering of new Hi-Luminosity magnetsPowering of existing LHC magnet circuits

Objective: provide flexibility in the location of the power converters and of the cryostats containing the current the leads in cases where space is limited and the radiation environment harsh. Use long distance superconducting links between power converters and magnets

Why MgB2 for the LHC Hi-Luminosity Upgrade

A. Ballarino, CERN

Itot 3 MA48 Cryostats1200 HTS Leads

Powering the LHC circuits

A. Ballarino, CERN

Powering the Hi-Luminosity LHC circuits

P1

P6 P4

P2

P8

P3

P5

P7

P1

P6 P4

P2

P8

P3

P5

P7

Betatron Cleaning Collimators

CMS

ATLAS

Where in the LHC ?

A. Ballarino, CERN

Superconducting Links

Superconductor operating at higher temperature: simplified (He gas) and relaxed (temperature margin) cryogenic cooling

Tunnel

Surface

1.9 K

5 K

T 25 K

Maximum operating temperature of the cable = 25 KHe gas cooling

Operation in self-field (B <1 T)

A. Ballarino, CERN

Superconducting Links Specification

A. Ballarino, CERN

-Total number of superconducting links planned to be installed in the LHC: 8

Lenght of superconducting links: 300 m to 500 m Multi-cable assembly Cable current rating: up to 20 kA Number of cables inside the link: up to 50 Total current capability: up to 150 kA

Total length of superconductor > 1000 km (7 tons)

MgB2 wire specification

Ic(20 K, 0.5 T) > 500 AIc(25 K, 0.5 T) > 400 AIc (30 K, 0.06 T) > 300 AJc,eng(20 K, 0.5 T) > 630 A/mm2

Jc,eng(25 K, 0.5 T) > 500 A/mm2

Jc,eng(30 K, 0.06 T) > 380 A/mm2

n-value (25 K, 0.5 T) > 30 Φ of strand < 1 mmCopper stabilizer 12 %RRR Copper stabilizer* > 80 Bending radius* < 100 mmCritical tensile strain (RT)* > 0.3 %Unit length 1000 m

A. Ballarino, CERN

MgB2 wire

3.60.67 mm2 1.61.6 mm2

1.11.1 mm2

Ni Matrix12 MgB2 filamentsCu core – Fe barrierff 14 %

Monel Matrix30 MgB2 filaments Nb + Ni barrierff 10.4 %- 18 %

= 0.98 mm = 0.85 mm

A. Ballarino, CERN

Wire produced at Columbus Superconductors, Genova

MgB2 wire

2012 20132008Year

+ uniform Ic+ 0.3 %+ RB 100 mm

A. Ballarino, CERN

H 4 m

L = 20 m SC Link Test Station @ CERN

A. Ballarino, CERN

MgB2 cables

20 kA Six cables, = 19.5 mm

Concentric 3 kASeven cables, = 8.4 mm

0.4 kAFour cables

0.12 kAEighteen cables

ext 65 mm

18 MgB2 wires = 6.5 mm

CuMgB2 , = 0.85 mm

Hi-current MgB2 cables – Ex LHC P1 and P5

A. Ballarino, CERN

Mass 11 kg/m(880 kg for H=80 m)

Itot= 150 kA

H=80 mL 24 cm

RB1.5 m

Semi-flexible cryostat external diameter = 220 mm

Hi-current MgB2 cables – Ex LHC P1 and P5

A. Ballarino, CERN

18 MgB2 wireswire = 0.98 mmCable = 6.5 mmTw = 400 mmLtot=210 m

LHe (L=2 m)

GHe (L=10 m)T < 1 K

+ -

5000 A

= 6.5 mm

10507 A

Measurement on MgB2 cables, 210 m

LHC Nb-Ti cable6 kA Operated at T<6 K

3 6 kA

A. Ballarino, CERN

Measurements on MgB2 cables, 220 m

Reached 20 kA at 24 K in two cables, each 20 m long, operated at CERN at 24 K in forced flow of helium gas(20th of February 2014)

Record in current in MgB2 cables

operated at higher temperature

A. Ballarino, CERN

2013 202320182017201620152014

SC Links at LHC P7

SC Links atLHC P1 and P5

Test ofhorizontal lines

Test ofvertical lines

20 m 60 m

Series P7 Series P1 and P5

Conductor for series

Timeline

A. Ballarino, CERN

Thanks for your attention !