Presentation on theme: "Michał Wiśniewski Adam Mickiewicz University in Poznań, Poland Technology and structure of superconducting devices."— Presentation transcript:
Michał Wiśniewski Adam Mickiewicz University in Poznań, Poland Technology and structure of superconducting devices
1. Introduction 2. Current lead 3. Systems with large magnetic field gradient 3.1. DECRIS 4. Systems with great homogeneity of magnetic field 4.1 Systems with superconducting shielding
Superconductivity in nuclear physics: 1. Spectroscopy 2. Accelerating particles 3. Ion Source Heating and cooling
Historical view: 1. Copper – several W 2. HTS with silver matrix 3. HTS with silver-gold alloy matrix – several mW
Magnetic field distribution for two conductors (1. in superconducting state, but without current, 2. is with 100A current) The maximum field from one superconducting tape is about 0,02 T. Magnetic field distribution for two conductors, both with 100A current. Bmax is about 0,04 T. Taking into account the magnetic field value generated by those superconducting tapes, One can see, that Ic.max value is decreasing about 30-40%.
1,2 –Copper leads 6 – Exchanger of heat on a 40 K level 10 – Textile structural element, with HTS elements of current leads on it 7 – Exchanger of heat on a 4 K level
DECRIS Ion source is one of the most important elements of accelerators, for example nuclotron One of the most often used ion sources is ECR type ion source
Magnetic field gradient up to 100 T/m It can work continuos for several years Using crycooler cooling causes bigger automation and it is decreasing the cost of upkeep
Because of necessity of keeping up magnetic field homogeneity, often superconducting key blockers are used. They are closing the electric circuit after supply magnets. It freezes a magnetic flux generated by electromagnet. Umożliwiają odłączenie układu zasilania przy zachowaniu strumienia magnetycznego.
Superconductors can be used to shield magnetic field. Shielding can be explained by pushing up the magnetic field outside the superconductor - Meisner effect.
To increase magnetic field homogeneity opened magnetic shields are used. They are planed to be used at the electron cooling system of ion beam at the NICA project.
Results of the research, is shown in the picture:
Without magnetic shields With magnetic shields
Other devices, which uses superconducting elements: Resistance current limiter
In closed magnetic shields, area inside is completely shielded. This effect is used for example in superconducting current limiters.
Dr Stanislav Z. Pakuliak (BLTP, JINR, Dubna) Dr Władysław Chmielowski (JINR, Dubna) Dr hab. Roman Zawodny (UAM, Poznań) Dr Henryk Malinowski (VBLHE, JINR, Dubna)