J.Fleiter, A.Ballarino Superconductivity Practical Days at CERN
26 th -27 th February 2015 Jerome Fleiter and Amalia Ballarino With
the collaboration for the practical exercises of: P. Denis, E.
Seiler and J. Hurte JUAS 2015 16/02/2015 1
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J.Fleiter, A.Ballarino 10 to 12 participants Hands-on practical
work in CERN laboratories Guided by experts When ? On the 26 th and
27 th of February Where ? In the Superconductor Laboratory,
Building 163 JUAS 2015 16/02/2015 2 Program and Organization Main
entrance B. 163
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JUAS 2015 16/02/2015 J.Fleiter, A.Ballarino 3 Practical Days at
CERN (1/2) Visit of Superconductor Laboratory, Building 163 Test
stations for the measurement of: Critical current of
superconductors (strands and cables) at liquid He temperature (1.9
K and 4.2 K, up to 15 T and up to 35 kA); Magnetic properties of
superconductors (magnetization curves) at variable temperatures and
fields (VSM); Residual Resistivity Ratio, Resistivity as function
of temperature; Cabling machine for accelerator Rutherford cables;
Laboratory for analysis of superconductors; Nb-Ti, Nb3Sn, YBCO,
BSCCO 2223 and MgB2 strands and cables Visit of Laboratory, SM 18
Test stations for magnets
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JUAS 2015 16/02/2015 J.Fleiter, A.Ballarino 4 Practical Days at
CERN (2/2) What will you do ? Measure electrical, magnetic and
thermal characteristics of superconducting samples with the purpose
of understanding the fundamental characteristics of superconductors
Superconductivity => Cryogenics
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J.Fleiter, A.Ballarino Definitions Superconductivity
Superconductivity is a phenomenon occurring in certain materials at
very low temperatures, (the Meissner effect) characterized by
exactly zero electrical resistance and the exclusion of the
interior magnetic field from Wikipedia Superconductor A conductor
that exhibit superconducting properties. It is an assembly of low
resistive metal and superconducting material. Cryogenics Cryogenic:
for Greek kryos", which means cold or freezing, and "genes" meaning
born or produced. In physics, cryogenics is the study of the
production of very low eye temperature (below 150 C, 238 F or 123
K) and the behavior of materials at those temperatures from
Wikipedia JUAS 2015 16/02/2015 5
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J.Fleiter, A.Ballarino Main properties of superconductors JUAS
2015 16/02/2015 6 Zero resistance Onnes measurement on mercury
(1911) Meissner effect Discovered by Meissner and Oschenfeld (1933)
For T
J.Fleiter, A.Ballarino Superconductors @ CERN Only few
superconducting materials could be used as superconductor for large
scale application Low Temperature Superconductors: Nb-Ti (T c =9K,
B c =15T) LHC machine Nb 3 Sn (T c =18 K, B c =30T) Hi Lumi-LHC
(2017) MgB 2 (T c =39K, B c =30T) Hi Lumi-LHC (2022) High
Temperature Superconductors: Bi 2 Sr 2 Ca 2 Cu 3 O 10+x (T c =108
K, B c >100 T) LHC machine Bi 2 Sr 2 CaCu 2 O 8+x (T c =95 K, B
c >100 T) High energy-LHC (>2030) YBa 2 Cu 3 O 7-x (T c =93K,
B c >100 T) High energy-LHC (>2030) JUAS 2015 16/02/2015 12
Superconductors in form of tape or wire used to make cables
J.Fleiter, A.Ballarino We will work with cryogenics and
superconductivity to understand and verify the unique properties of
superconductors YBCO 123 bulk BSCCO 2223 tape SmCo, NeFeB magnets
Liquid nitrogen Levitation Flux pinning Zero resistance Jc,Tc,Hc
Superconductivity Practical Days at CERN JUAS 2015 16/02/2015
14
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J.Fleiter, A.Ballarino 1.Levitation experiment 2.Flywheel
demonstration 3.Critical temperature experiment 4.Zero resistance
experiment 5.Critical current experiment 6.Resistive transition
experiment Experiments JUAS 2015 16/02/2015 15 Experiments will be
performed with HTS superconductors
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J.Fleiter, A.Ballarino HTS Liquid nitrogen Superconductivity
Cryogenics Superconductors you will use for the experiments at
CERN: YBCO 123 Melt Textured Bulk.Tc= 93 K BSCCO 2223 Tape Tc= 110
K You will use Nitrogen 78% of atmosphere Boiling point (1 atm): 77
K (-196 C) Colorless, odorless, non-toxic Dealing with LN2: safety
first (skin burn, splashing..) JUAS 2015 16/02/201516 4 mm 0.2 mm
HTS SmCo
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J.Fleiter, A.Ballarino Levitation experiment HTS SmCo HTS SmCo
Appreciate the intensity of the max levitation force ! Understand
the Meissner effect and flux pinning JUAS 2015 16/02/2015 17
Levitation experiment
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J.Fleiter, A.Ballarino Critical temperature experiment
Measurement of critical temperature by using the Meissner effect.
JUAS 2015 16/02/2015 18 The critical temperature is defined as the
temperature measured on the superconductor when the permanent
levitating on it comes to complete rest on the superconductors
surface. Critical temperature experiment
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J.Fleiter, A.Ballarino A superconducting tape and a pure silver
tape are connected in series, Measure the voltages (resistances) as
the specimens are inserted into liquid nitrogen and cooled to 77 K.
HTS:BSCCO 2223 multi-filamentary tape in silver alloy matrix. Zero
resistance experiment A see-through glass walled dewar is used for
the LN 2. Ag (293 K) 1.4610 -6 m Ag (77 K) 0.2 Ag (293 K) JUAS 2015
16/02/2015 19 Zero resistance DC experiment
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J.Fleiter, A.Ballarino Critical current experiment Critical
current (I c ): current at which a specified electric field
criterion E c, or resistivity criterion c is achieved in the
specimen. Losses through a Type II superconductors (H c1