Bridging Big Science and Industries for 20+ years

CERN is the European Organization for Nuclear Research and is an organisation working to shed light on fundamental questions such as what the universe is made of and how it works…

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Bridging Big Science and Industries for 20+ years

FREIA is the Swedish Facility for Research Instrumentation and Accelerator Development at Uppsala University. Here engineers and physicists work on the development of particle accelerators and instruments for physical measurements…

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Bridging Big Science and Industries for 20+ years

GSI Helmholtz Centre for Heavy Ion Research is a German research centre based in Darmstadt. GSI develop, build and operate particle accelerators that are essential in the search for a deeper understanding of the structure of matter and the development of the universe…

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CERN is the European Organization for Nuclear Research and is an organisation working to shed light on fundamental questions such as what the universe is made of and how it works.

 

CERN specialises in particle physics and builds the particle accelerators needed to perform experiments in this field of science. The CERN facilities has about 2.500 employees on their payroll and in addition 15.000 people from around the world work together to push the limits of knowledge.

 

Over the years three Nobel Prizes have been awarded to scientists at CERN. There are several active particle accelerators at CERN, where the most powerful one is the Large Hadron Collider (LHC), which is the largest single machine ever built.

 

The LHC is an underground circular particle accelerator with a circumference of 27 km, which accelerates protons and other particles to near speed of light velocities, before smashing them together in order to study the fundamental interactions of nature.

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FREIA is the Swedish Facility for Research Instrumentation and Accelerator Development at Uppsala University. Here engineers and physicists work on the development of particle accelerators and instruments for physical measurements. Particle accelerators, like those used at GSI and CERN, facilitate research in high energy physics and the structure of materials. Among the projects at the FREIA lab are corrector magnets and crab cavities. These are being developed and tested for the future upgrade of the luminosity of the Large Hadron Collider (HiLumi-LHC). This will pave the way for even more elaborate experiments to be performed at the CERN facilities.

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GSI Helmholtz Centre for Heavy Ion Research is a German research centre based in Darmstadt. GSI develop, build and operate particle accelerators that are essential in the search for a deeper understanding of the structure of matter and the development of the universe. Around 1.400 people are employed at GSI, and the particle accelerators and synchrotrons at GSI have thus far facilitated the discovery of six elements in the periodic table, among others Darmstadtium, named after the location of the centre. One of the largest research projects worldwide is the Facility for Antiproton and Ion Research (FAIR), which is currently being built at GSI. One component of the FAIR facility is the SIS100 ring accelerator, which will allow for the acceleration of all the natural elements in unparalleled quality and intensity. The FAIR project will enable scientists to recreate extreme conditions found in cosmic events, like exploding stars. This will give new insights into the structure of matter and the evolution of the universe.

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Introducing M&W Big Science.

M&W Big Science offers customers a range of well-proven current leads designs, optimised towards current, heat leak, coolant types and application.

We offer our customers access to 20+ years of experience and a network of specialists and likeminded people.

M&W Big Science takes full ownership of the entire process starting with concept, design, engineering, production, FAT and thorough documentation.

A project can be the development of a prototype, a small series, or a high-volume production.

Our commitment is always the same:

In addition to unparalleled quality you get an optimised current leads which will serve your installation well and be in operation for years to come.

The Big Science market consists of large research facilities, scientific test centres and is often funded by governments or groups of governments. In many scientific fields, major progress is only achieved through Big Science facilities, which are needed to perform exotic experiments.

The unique mechanical and electrical engineering competences and high level of craftsmanship of M&W Big Science enables us to offer products and solutions to the demanding customer base, where quality, durability and precision is key.

 

M&W Big Science Brochure

Contact information.

Torben Paulli Andersen (TPA)

Torben Paulli Andersen

Chief Developer of Current Leads

Torben Ekvall (TEK)

Torben Ekvall

Co-CEO and Owner

100 meters below ground in a 27 km long ring, particles are being accelerated clock-wise and counter clock-wise.

cern tube
  1. Each beam contains 3.000 ‘bunches’ of particles, with 100 billion particles in each bunch.
  2. When two bunches collides, only about 40 particles that crash head-on.
  3. 1 billion particle crashes happen every second.
  1. The velocity of the proton beams reaches 99,9999991% of the speed of light in the LHC which makes them revolve 11.245 times each second.
  2. The energy of the accelerated protons is 6,5 TeV, yielding collisions of 13 TeV in the desired head-on collision.

M&W Big Science Delivers Optimised Superconducting Current Leads.

  • The CERN facility has about 10 accelerators that have been built gradually over the last 50 years.
  • The LHC is built in tunnels previously used for the Large Electron-Positron Collider, which was dismantled in 2001.
  • Mark & Wedell has delivered current leads to CERN with currents ranging from 60 A – 13.000 A.
  • One of Mark & Wedell’s most prominent deliveries to the LHC was 410 current leads for ‘corrector’ dipole magnets, used for keeping the LHC particle beam under control.
  • Furthermore current leads with varying operating currents have been delivered to CERN, mostly for magnet testing purposes.
  • The power consumption of the LHC in full operation is equivalent to the power production of seven 10 MW wind turbines in full operation.
  • 1.232 bending dipole magnets direct the particle beams around the circular accelerator.
  • Each dipole magnet has a magnetic field of 8,33 T, and is kept at a temperature of 1,9 K, which is colder than outer space!
  • The dipole magnets are 15 m long and weigh around 35 t each.

The Large Hadron Collider (LHC) is the world’s largest and most powerful particle accelerator and the largest scientific test instrument ever built. The collider is a 27 km long circular accelerator placed 100 m underground. The particles are accelerated in 2 independent vacuum tubes, with one beam traveling clock-wise and one beam traveling counter clock-wise.

The particle accelerators accelerate protons and other particles to near the speed of light, before smashing them together at so-called collision points. This is done in order to study the fundamental interactions of nature. The LHC was built to test the Standard Model of particle physics: a classification of all known elementary particles – the building blocks of the world around us. In 2012 the LHC confirmed the detection of the Higgs Boson, which was predicted in 1964. Mark & Wedell has so far developed and supplied CERN with more than 450 superconducting current leads units.

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Selected Project References.

GSI, Darmstadt

Project: 6 kA for Quadropol magnets

Experiment: SIS100 / FAIR

Current: 6 kA

Number of units: 4 pairs

M&W Type: CvHH

2020

CEA, Saclay

Project: MQ/MQYY magnets for CERN/HiLumi

Experiment: STAARQ

Current: 13 kA

Number of units: 1 pair

M&W Type: CvHNH

2019

ASG Superconductors

Project: Current leads (1st batch of series)

Experiment: SFRS

Current: 300 A

Number of units: 8 pairs

M&W Type: CvH

2019

Elytt Energy

Project: Current leads

Experiment: SFRS

Current: 300 A

Number of units: 23 pairs

M&W Type: CvH

2019

Uppsala University

Project: Copper current leads for testing of HiLumi magnets

Experiment: FREIA

Current: 2 kA

Number of units: 2 pairs

M&W Type: CvH

2018

ASG Superconductors

Project: Current leads (preseries)

Experiment: SFRS

Current: 300 A

Number of units: 11 pairs

M&W Type: CvH

2017

ASG Superconductors

Project: Current leads (prototype)

Experiment: SFRS

Current: 300 A

Number of units: 1 pair

M&W Type: CvH

2016

GSI

Project: HV Isolated amplifier for Cernox sensor

Experiment: SIS100/FAIR

Current: n.a.

Number of units: 40 units

M&W Type: n.a.

2014

GSI

Project: HTS current leads with copper tubes

Experiment: SIS100/FAIR

Current: 14 kA

Number of units: 19 pairs

M&W Type: CvHH

2013

GSI

Project: HTS current leads with copper tubes (prototypes)

Experiment: SIS100/FAIR

Current: 14 kA

Number of units: 2 pairs

M&W Type: CvHH

2013

GSI

Project: Study of HTS current leads

Experiment: SIS100/FAIR

Current: n.a.

Number of units: Study report

M&W Type: n.a.

2011

GSI

Project: Current leads

Experiment: SIS100

Current: 11 kA

Number of units: 2 pairs

M&W Type: CvHH

2004

CERN

Project: Conductors for current leads prototype

Experiment: LHC

Current: 120 A

Number of units: 4 units

M&W Type: CvH

2003

CERN

Project: Current leads assemblies for LHC

Experiment: LHC

Current: 60 A

Number of units: 410 units

M&W Type: CdH

2002

CERN

Project: Current leads for magnets test

Experiment: LHC

Current: 13 kA

Number of units: 13 pairs

M&W Type: CvHH

2000

CERN

Project: Current leads for magnets test

Experiment: LHC

Current: 600 A

Number of units: 26 pairs

M&W Type: CvH

2000

CERN

Project: Current leads utilising HTS

Experiment: LHC

Current: 13 kA

Number of units: 1 pair

M&W Type: CvHH

1998

CERN

Project: Current Feedthrough Prototype

Experiment: LHC

Current: 6.5 kA

Number of units: 1 unit

M&W Type: CvH

1998

Product Overview.

There are a great variety of current leads designs depending on performance, scale, complexity and applications. The designs are optimised based on specifications or limitations of the set-up, such as operating current, coolant type, coolant consumption and dimensions.

M&W current leads type CVHH suitable for currents above 10.000 A

This principal sketch illustrates a M&W current leads type CvHH that is suitable for currents above 10.000 A. The current enters the warm terminal and exits at the cold terminal. The current leads consists of different sections where different materials and coolants are used.

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Bridging Big Science and Industries for 20+ years.

Theory of Thermodynamics and Electromagnetism
Theory of Thermodynamics and Electromagnetism
Products
Products
Superconducting Electromagnet
Superconducting Electromagnet

The bridge between the warm and the cold terminal.

Current leads are a key component in any superconductor technology. It leads the current from the ambient temperature of 20 ⁰C to the cold environment where the superconducting wires are operated. The superconductor must be cooled to cryogenic temperatures, which for low temperature superconductors is around 4 K (-269 ⁰C). At this temperature, the superconductor enters its superconducting state and has no electrical resistance.

 

Particle accelerators use strong magnetic fields either to bend or to focus/de-focus the particle beams. To create such a strong magnetic field, strong superconducting electromagnets are required. These magnets rely on thin superconducting wires that can carry huge electrical currents, thanks to zero resistance, and can thus create very strong magnetic fields, in the range 1-10 T.Thousands of amps are entering the current leads through the warm terminal that consists of a massive copper block and exits through the cold terminal in a tiny superconducting wire.

 

In the following you will see how this transition between the large copper conductor at the warm terminal and the small superconductor at the cold terminal looks like.

Copper wires: the problem
Copper wires: the problem

When an electrical current passes through for instance a copper wire, the wire will heat up. This is due to thermal losses in the wire coming from the electrical resistance in the copper. If the wire surroundings cannot keep the material below a certain temperature, the wire will overheat and eventually melt-down. Therefore there is a limit to how much current any given copper wire can lead. The image on the left shows copper wires connected to the warm end of a current leads, and the copper wires are capable of carrying 15.000 A.

A thicker copper wire can of course carry more current, but the thousands of amps required to create the strong magnetic field required in particle accelerators, would make the copper cable too thick and impractical, and at the same time generate a lot of thermal losses.

Superconducting wires: the solution
Superconducting wires: the solution

Some materials lose their electrical resistance at low temperatures. These materials are called superconductors and they do not have any ohmic losses when an electrical current is passing through them. This makes superconductors ideal as conductors in electromagnets where huge magnetic fields shall be achieved. The image on the left shows Niobium-Titanium wires, also capable of carrying 15.000 A. The current density in these wires is 4-500 times larger than the current density of similar copper wires.

Superconducting materials become superconducting below a certain transition temperature, also called critical temperature Tc, whereas non-superconducting materials still have a finite resistance, even at 0 K (-273 ⁰C). The resistance of these two types of materials is shown in the following figure, where the resistance as a function of temperature is illustrated.

The superconducting state of the material also depends on the applied magnetic field and the current, but in most applications, the superconductor supports a current density which is hundreds of times larger than that of copper wires.

Known superconductors and the search for new ones
Known superconductors and the search for new ones

Scientists keep discovering new types of superconductors, and superconductors with a high transition temperature are highly sought-after. Some of the recent discoveries include superconductors with transition temperatures at almost room temperature, but only under extreme conditions, such as a pressure of 155 GPa!

The technology behind our superconducting current leads.

Current leads come in many shapes and forms depending on the specification and applications. There are many considerations to take into account when designing a current lead.

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What is the operating current?

The typical operating current is from a few hundred to tens of thousands of amps. The current density changes dramatically through the current leads. For a 12 kA CL, for instance:


  • The normal conducting warm terminal can have a cross section of 40 cm2 and a current density of 300 A/cm2
  • The superconducting cable at the cold terminal can have a cross section of 0,10 cm2 and a current density 125.000 A/cm2

Thus the current density is increased with a factor of about 400.

WHICH COOLANT TYPES CAN BE USED?

  • For example in section 1, liquid nitrogen and its boil-offs can be used as coolants. The interception point (the point where section 1 and 2 meet) must be kept below the critical transition temperature of the HTS material, which is above the boiling point of liquid nitrogen (77 K). This makes nitrogen an ideal coolant for this section.
  • At the cold end liquid helium is used and the boiled off gaseous helium is used as coolant in section 2. Most LTS materials become superconducting below 10-15 K. Liquid Helium temperature is around 4 K, and is thus an ideal coolant at the cold terminal.

WHAT ARE THE SPATIAL DIMENSIONS OF A CL?

  • At low current the size does not have to be more than the size of a walking stick. For very high current it can be 2 metres long, 30 cm in diameter and weigh 150+ kg.

WHAT TEMPERATURE IS THE CURRENT LEADS OPERATED AT?

  • The warm end of the current leads is kept at room temperature (300 K).
  • The current leads are sometimes anchored at an intermediate temperature (typically 50-80 K) in the middle.
  • The cold terminal is typically cooled by liquid helium to a temperature of around 2-4 K.

WHAT IS THE TYPICAL LHE CONSUMPTION?

The coolant consumption depends very much on the application and the operational conditions.


  • If the CL is only used for a couple of tests a year, a simple helium based CL would suffice (CvH) . Then a 10 kA CL consumes about 35 litres liquid helium per hour.
  • If however the CL is used in multiple and/or continuously running experiments, a more advanced solution using HTS and Nitrogen as additional coolant (CvHNH) is ideal. In this case the liquid Helium consumption for a 10 kA CL would be reduced to less than 2 litres per hour. About 15 litres of liquid nitrogen per hour would then also be required.

WHAT KIND OF MATERIALS IS A CL MADE OF?

  • The normal conducting part (section 1) of any of our current leads will consist of high quality copper.
  • The HTS part (section 2) of our current leads could for instance consist of BSCCO (bisko) or REBCO materials. Additionally, high grade stainless steel is used as support structure and quench protection.
  • The LTS part of our current leads could for instance consist of NbTi.

WHAT KIND OF MEASURING EQUIPMENT CAN BE INSTALLED?

  • Our current leads are normally fitted with multiple sensors for voltages and temperatures measurements. In addition heating elements are installed in the warm terminal.
Current Lead

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