Michał Wiśniewski

Adam Mickiewicz University in Poznań, Poland

Technology and structure ofsuperconducting devices

1. Introduction2. Current lead3. Systems with large magnetic

field gradient3.1. DECRIS4. Systems with great

homogeneity of magnetic field4.1 Systems with superconducting

shielding

Superconductivity in nuclear physics:

1. Spectroscopy2. Accelerating particles3. Ion SourceHeating and cooling

Historical view:1.Copper – several W2.HTS with silver matrix3.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 leads6 – Exchanger of heat on a 40 K level10 – Textile structural element, with HTS elements of current leads on it 7 – Exchanger of heat on a 4 K level

DECRISIon 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

LN2

Zbiornik

Kriochłodziarka

Kriostat

Przepusty prądowe

Izolacjaelektryczna

LN

Nadprzewodnik

SUPERGANTRI (planed)

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)