Transcript magnetic field - Indico

Database Design for
Superconducting Magnets
CERN Summer Student 2006
Tae-Joon Cho (Cambridge)
Under supervision of
Dr. Walter Scandale (CERN)
Emanuele Laface (CERN)
16 August 2006
Database design for superconducting magnets
Contents
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Magnets and Magnetic Field B
Superconductors
Parameters
Database survey and Collaborations
Conclusions
Bibliography
(History) Development of Superconductivity
Database design for superconducting magnets
Magnets & Magnetic Field B
• A magnet is an object that has a magnetic field.
– Permanent magnets (Permagnets) & Electromagnets.
e.g. Dipoles, Earth, Solenoids etc.
• A magnetic field is that part of the electromagnetic field that exists when
there is a changing electric field.
Database design for superconducting magnets
?
Superconductors I
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Superconductivity is a phenomenon occurring in
certain materials at extremely low temperatures (~ a
few K), characterized by exactly zero electrical
resistance and the exclusion of the interior magnetic
field (the Meissner effect)
Superconductivity  lim0(normal conductivity)
–
Superconductivity is a quantum mechanical phenomenon
•
Meissner effect  Faraday’s / Lenz’s Law
•
Applications
–
•
MRI, Particle Accelerators, etc.
A comparison of Magnetic Field Strengths
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•
<Magnetic Levitation above a Superconductor>
Dipole BD : T ~ mT
Earth’s BE : 30T ~ 60T
ATLAS BATLAS : ~ 2T
CMS BCMS : ~ 4T
103 ~ 105!
A comparison of Typical Currents
– Laptop : A ~ mA
– A voltage source 220V, a resistance 220k  1mA
 mag(B) ~ 2T, I ~ 10,000,000A  P ~ 1016kW
– LHC requires ~ 12000A
http://www.cartoonstock.com
Database design for superconducting magnets
Superconductors II
Fie
ld
Jc
Niobium Titanium (NbTi)
(te
sl
a)
c
Bc2
Current density (kA.mm-2)
T
r
pe
em
)
(K
e
r
at u
 NbTi is a ductile Alloy
 Superconductivity below
the surface
 Upper
Bc
First detailedcritical
study in 1961field
(John K.Hulm
and Richard D.Blaugher) from
 Critical
temperature 
Westinghouse Research Laboratories in c
Pittsburgh, Pennsylvania)
 Critical
current density
Jc(Bc,c)
Database design for superconducting magnets
Superconductors III
• Niobium-Titanium (NbTi)
– Detailed study in 1961
– Critical temperature ~ 9K at 0T
• Niobium-Tin (Nb3Sn)
– Detailed study in 1954
– Critical temperature ~ 18K at 0T
– Brittle  Ductile
 Filaments
x
Coolant (liquid He ~ 4K)
 Higher critical field B
Database design for superconducting magnets
Parameters
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Critical temperature c
Upper critical field Bc
Critical current density Jc (Bc, c)
Ductility
Phase transitions
Mechanical/Physical/Chemical properties
 More than 100 parameters
Database design for superconducting magnets
Database Survey
http://sdb.web.cern.ch/sdb/
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Database design for superconducting magnets
Collaborations
• LHC at CERN
• Tevatron at FermiLab
• HERA (Hadron-Electron Ring Accelerator) in Hamburg,
Germany
• FAIR at GSI in Frankfurt, Germany
• ITER (International Thermonuclear Experimental Reactor) in
France
• J-PARC (Japan Proton Accelerator Research Complex) at
KEK in Japan
• KEKB (Electron-positron colliding-beam accelerator) in
Tsukuba Campus at KEK in Japan
• ILC (International Linear Collider project) at KEK in Japan
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Database design for superconducting magnets
Conclusions
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Increasing demand on superconductors
More theoretical & experimental developments
R&D on Permanent magets
Recognition of main parameters
Inter-relations of those parameters
Collaborations
User friendly Database (Oracle SQL)
Database design for superconducting magnets
Thank you for your
attention!
?
Database design for superconducting magnets
Bibliography
• Superconducting Magnets – Chapter 12 & 13
– Martin N. Wilson (Oxford University Press)
• Practical Low-Temperature Superconductors for Electromagnets
– A. Devred (CERN Report 2004)
• Superconducting magnet technology for particle accelerators and detectors
– T. Taylor (CERN Summer Student Lecture, 14 July 2006)
• Wikipedia (http://www.wikipedia.org/)
http://sdb.web.cern.ch/sdb/
History
Development of
Superconductivity
In 1911, the group led by Heike Kammerling-Onnes (1853  1926, Netherlands) in a
laboratory of Leiden University discovered superconductivity for the first time.
• In 1933, Walter Meissner (1882  1974, Germany) and Robert Ochsenfeld (1901  1993,
Germany)
discovered
total expulsion of the
external magnetic
fieldsstarted
from superconductors
In 1908,
Heikethe
Kammerling-Onnes
(18531926,
Netherlands)
his
 Meissner
/ Meissner-Ochsenfeld
careereffect
by building
liquefiers and was effect.
the first to produce liquid helium (TB ~
4.2K)
used later London
to investigate
electrical
properties ofand
metals
at London
low
• In 1935,
Fritz Wolfgang
(1900the
 1954,
Germany-USA)
Heinz
(1907 
temperature.
In
1911,
one
of
his
students,
Gilles
Holst,
observed
that
the
1970, Germany) showed that the Meissner effect was a consequence of electromagnetic free
of aofmercury
wire completely
at Theory.
a temperature slightly
energy resistance
minimisation
superconducting
currentvanished
 London
below 4.2K. Kammerling-Onnes called it the superconducting state.
• In 1941,
Lev Davidovich Landau
(1908the
 1968,
addressed
his theory
of second-order
(Kammerling-Onnes
was awared
1913 USSR)
Nobel Prize
in Physics
‘for his
phase transitions
with
Schrodingerlike
equation
successful to
describe
investigations
onathe
properties of matter
at low temperatures
which
led to the
the macroscopic
properties
of superconductors.
production
of liquid helium.’)
• In 1950, and
Vitaly
Lazarevich
2006,
USSR) earned
the phenomenological
Landau’s
theory
to explainGinzburg
why liquid(1916
helium was
super-fluid
him the 1962
Ginzburg-Landau
Theory.
Nobel Prize for Physics.
• In 1957, John
 1991, USA),
Cooper
 , USA) and
It had Bardeen
been noted(1908
experimentally
that if Leon
liquid Neil
helium
at these(1930
low temperatures
wasJohn
Robert Schrieffer
 then
,USA)
published
microscopic
theory
of superconductivity,
placed in a(1931
beaker,
it climbed
outthe
of the
beaker until
the level
outside was equal the
concept oftoCooper
pairs
was introduced.
that inside.
Similarly
liquid helium would climb into the beaker if the level outside
that in the beaker.
Landau
devised
a theoryshowed
to explain
behaviour
• In 1957, exceeded
Alexei Alexeyevich
Abrikosov
(1928
 , USSR)
thatsuch
Ginzburg-Landau
In 1972,
the
microscopic
theory
of
superconductors
earned
its
authors,
Bardeen,
Cooper
and
Schrieffer the
which was
in 1941.
It predicted ainto
newthe
phenomenon,
namely
a temperature
theory predicts
the published
division of
superconductors
two categories
now
referred
to as
Nobel
Prize
in
Physics
‘for
their
jointly
developed
theory
of
superconductivity,
usually
called
the BCSwave
described
a
"second
sound",
and
three
years
later
experimental
evidence
Type I and Type II  the theory of the mixed state of type-II superconductors by analogy with
theory’.
produced
in Moscow
themagnetic
existencevortices
of "second
sound". was introduced.
superfluidity
in helium
and theconfirmed
concept of
/ fluxoids
<Landau>
•
In 2003, Abrikosov and Ginzburg alongside Anthony James Legget (1938  , UK) were awarded Nobel Prize for
pioneering contributions to the theory of superconductors and superfluids.
 More
developments
and
<Heiketheoretical
Kamerlingh Onnes> <The
First Measure of Superconductivity>
<John Bardeen>
to come!
<First Temperature vs. Resistance
Graph for a High Tc Superconductor>
<Leon Neil Cooper> <John Robert Schrieffer>