2 sujets /DACM/LEAS

Dernière mise à jour : 22-08-2019


 

Contribution to the high gradient and large aperture superconducting accelerator magnets developments using of high magnetic field superconductors

SL-DRF-19-0768

Research field : Electromagnetism - Electrical engineering
Location :

Département des Accélérateurs, de Cryogénie et de Magnétisme (DACM)

Laboratoire d'Etudes des Aimants Supraconducteurs (LEAS)

Saclay

Contact :

Thibault LECREVISSE

Pascal TIXADOR

Starting date : 01-10-2019

Contact :

Thibault LECREVISSE

CEA - DRF/IRFU/DACM/LEAS

+33 (0)1 69 08 68 27

Thesis supervisor :

Pascal TIXADOR

CNRS -

Laboratory link : http://irfu.cea.fr/dacm/Phocea/Vie_des_labos/Ast/ast_groupe.php?id_groupe=297

The Large Hadron Collider (LHC) at CERN is now in exploitation phase. The European physicians on particle physic community has already started the conceptual studies for the Future Circular Collider (FCC) with a collision energy increase to nearly 100 TeV to go deeper in the LHC studies possibility (14 TeV). Such a device would keep the leadership position of the European community in term of high energy physics. In the interaction (IR) area of this accelerator, few specific quadrupole magnets are needed in order to increase the luminosity (the number of collision with time unit) and the statistic related to new particles discovery. Such magnets have to generate a high magnetic field gradient in the largest possible aperture. High Field Superconductors (HFS, also called High Temperature Superconductors: HTS) would find here a use justification considering the higher cost compared to classical Low Temperature Superconductors (LTS).

We are proposing to demonstrate the feasibility of an interaction quadrupole magnet with a gradient over 150 T/m (1.5 time the FCC IR quadrupole gradient) in an aperture of 210 mm (design FCC). Such magnets will require specific design consideration and optimization, new winding technics and insulation process to be able to protect it against fast resistive transition.

The PhD student will interact with DACM team in order to design a quadrupole magnet corresponding to the accelerators requirement. A design step will be necessary in order to develop the fabrication process. Nevertheless the student will be able to look at specific aspect of the magnet fabrication, like the insulation or the protection aspects in such very high energy magnets.

Study of the Thermomechanical Behavior of the Superconductor Nb3Sn in Coils for Future Accelerator Magnets

SL-DRF-19-0486

Research field : Mechanics, energetics, process engineering
Location :

Département des Accélérateurs, de Cryogénie et de Magnétisme (DACM)

Laboratoire d'Etudes des Aimants Supraconducteurs (LEAS)

Saclay

Contact :

Etienne Rochepault

Olivier Hubert

Starting date : 01-10-2019

Contact :

Etienne Rochepault

CEA - DRF/IRFU/DACM

01 69 08 37 75

Thesis supervisor :

Olivier Hubert

ENS Pari-Saclay - LMT

01 47 40 22 24

Personal web page : https://www.researchgate.net/profile/Etienne_Rochepault

Laboratory link : http://irfu-i.cea.fr/dacm/index.php

In order to develop future particle accelerators such as the Future Circular Collider (FCC), high field superconducting electromagnets (higher than 15 T) are necessary. The superconductor Nb3Sn is aimed, however it causes some technical issues yet not solved during its production. The Nb3Sn is produced in the form of cables of the Rutherford type. These cables are then wound to form the coils of the electromagnet. Following winding, the conductor requires a heat treatment at 650°C in order to form the Nb3Sn superconducting phase. It is now established that significant dimensional changes of the strands occur during this phase change, translating in dimensional changes of the cables. If these changes in dimensions are not permitted by the tooling, mechanical stress add up in the coil and the superconducting performances degrade. Currently this issue is dealt with empirically by allowing clearances in central posts, around which are wound the superconducting cables, and by varying iteratively the clearances. However, the thermomechanical behavior of the Nb3Sn cables in a coil during the heat treatment needs to be quantified. The goal of this thesis is to observe and understand the changes of dimensions of this type of Nb3Sn conductors in order to help dimensioning the coil fabrication tooling for future accelerator magnets, and potentially improve their performances.

• Electromagnetism - Electrical engineering

• Mechanics, energetics, process engineering

 

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