Grigory L. Kuznetsov

Superconducting Magnets for the NICA Accelerator Complex in Dubna

NICA is the new accelerator complex being under design and construction at JINR. The facility is aimed at providing collider experiments with heavy ions up to Uranium in a center of mass energy range from 4 to 11 GeV/u and an average luminosity up to 1027 cm-2 · s-1. The collisions of polarized deuterons are also foreseen. The facility includes two injector chains, a new superconducting Booster synchrotron, the existing 6 A · GeV superconducting synchrotron-Nuclotron, and the new superconducting Collider consisting of two rings of about 500 m circumference each. The Booster synchrotron and the NICA Collider are based on an iron-dominated “window frame”- type magnet with a hollow superconductor winding analogous to the Nuclotron magnet. The status of the design and construction of the full size model magnets for the Booster synchrotron as well as for the NICA Collider is presented.

Superferric model dipole magnet with the yoke at 80 K for the GSI future fast cycling synchrotron

Experimental data of a fast cycling (f=1 Hz) 2T dipole magnet based on a superconducting NbTi multi filament hollow cable cooled with forced two phase helium flow at T=4.5K and iron yoke at T=80 K are presented. A new magnet design is proposed. The magnet yoke made of laminated steel consists of two parts: the internal smaller part has close mechanical and thermal contact with the coil while the outer part is separated from the cold mass with a gap of 1 mm and cooled with liquid nitrogen.

Superconducting Magnets for the NICA Accelerator Collider Complex

NICA is a new accelerator collider complex under construction at JINR. The facility is aimed at providing collider experiments with heavy ions up to Uranium in a center of mass energy range from 4 to 11 GeV/u and an average luminosity up to 1027 cm -2 s-1. The collisions of polarized deuterons are also foreseen. The facility includes two injector chains, a new superconducting booster synchrotron, the existing 6 AGeV superconducting synchrotron Nuclotron, and a new superconducting collider consisting of two rings, each of about 500 m in circumference. The booster synchrotron and the NICA collider are based on an iron-dominated “window frame”-type magnet with a hollow superconductor winding analogous to the Nuclotron magnet. The status of the development of the full size model magnets for the booster synchrotron as well as for the NICA collider is presented. The test results of model magnets are discussed. The status of the creation of a facility for serial tests of superconducting magnets for the NICA project is described.

Experimental study of a prototype dipole magnet with iron at T=80 K for the GSI fast cycling synchrotron

Two new prototype dipole magnets for the proposed new fast cycling (f=1 Hz) synchrotron at GSI in Darmstadt have been designed, fabricated and tested. The magnets are based on a window frame iron yoke cooled by liquid nitrogen and a superconducting winding made from a hollow NbTi composite superconductor cable cooled with forced two-phase helium flow at T=4.5 K. The cold mass of the magnet is separated from the yoke by a small vacuum gap of 0.75 mm to 2.5 mm. A decrease of ac power losses by a factor of 2.3 in comparison with a standard Nuclotron dipole is obtained. The design features of two prototype dipoles as well as the test results are presented.

Status of the Development of Superconducting Magnets for the NICA Project

NICA is a new accelerator complex that is being under design and construction at JINR. The facility is aimed at providing collider experiments with heavy ions up to Uranium in a center of mass energy range from 4 to 11 GeV/u and an average luminosity up to 1027 cm-2 s-1. The collisions of polarized deuterons are also foreseen. The facility includes two injector chains, a new superconducting booster synchrotron, the existing 6 superconducting synchrotron-Nuclotron, and a new superconducting collider consisting of two rings, each of about 503 m in circumference. The booster synchrotron and the NICA collider are based on an iron-dominated “window frame”-type magnets with a hollow superconductor winding analogous to the Nuclotron magnet. The status of the development of the full size model magnets for the booster synchrotron as well as for the NICA collider is presented.

New Results on Minimizing AC Power Losses in a Fast Cycling 2 T Superferric Dipole With a Cold Yoke

New results from the investigation of 2 T superferric model dipoles operating at 4 T/s, 1 Hz are presented. The works are performed within the R&D program on the design of the SIS100 synchrotron at GSI in Darmstadt. One of the main research goals is minimization of overall AC power losses in the magnet at 4 K level. Different modifications of the dipole were proposed and tested experimentally. By the present time, the losses are reduced to about 17 W/m of the magnet length, while the reference Nuclotron dipole produces about 38 W/m in the same operating mode. Essential design details of the model magnets are described and further R&D steps are outlined

Status of the Design of a Full Length Superferric Dipole and Quadrupole Magnets for the FAIR SIS 100 Synchrotron

The synchrotron SIS100 is one of the two basic accelerators of the future Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt. The SIS100 should provide acceleration of high intensity U28+ and proton beams for 0.5 s, with a pulse repetition rate of 0.6 Hz. In the accelerator magnetic system superferric 2 T dipoles of about 3 m length and 32 T/m quadrupoles of about 1 m length will be used. The magnet coils are made from hollow NbTi composite cable cooled with two phase helium flow at 4.5 K. The lattice comprises 108 dipoles and 168 quadrupoles. The elliptic beam pipe inner dimensions have been fixed at 130 times 60 mm2 for the dipole and 135 times 65 mm2 for the quadrupole. Both the dipole and quadrupole design approaches are based on improved versions of the original Nuclotron fast-cycling magnets and provide significantly less AC loss at 4.5 K, better quality of the magnetic field, and a higher long-term mechanical stability of the magnet coils. The results are based on the investigation of 1.4 m dipole and 0.4 m quadrupole Nuclotron-type magnet models. The status of the new magnets design and its manufacturing are presented. Essential features and new results are discussed.

Progress in the Design of a Fast-Cycling Cos - style Dipole based on High Current Hollow Superconducting Cable *)

The progress in the design of a fast-ramped, fast-cycling Cos-style 4 T dipole based on high current hollow superconducting cable is presented. New results obtained in the optimization of both the 40 kA hollow cable and the magnet coil structures are discussed. Experimental data from recent tests of the model dipole coil made from the NbTi keystoned wire are reported. The joint optimization of the angular distribution of the coil turns and the internal shape of iron boundary makes it possible to achieve a relative non-linearity of the magnetic field better than 5 • 10−4 within 82% of the coil aperture over a dynamic range from 0.3 T to 4.5 T. The diameter of the new hollow cable is 8.92 mm. It consists of 40 keystoned NbTi composite wires and a 3mm bore coolant tube. The designed operating current is 40.1 kA at 4.5 T. Full scale tests of the model dipole coil will be performed after completion of the necessary test facility upgrade. The actual maximum of 11.4 kA for the operation current is limited by the power supply and current leads of the test stand. The new current leads aimed at a current of 20 kA have been designed and manufactured.

Superconducting Magnets for the NICA Accelerator Collider Project

Nuclotron-based Ion Collider fAcility (NICA) is a new accelerator collider complex under construction at the Joint Institute for Nuclear Research. The facility is aimed at providing collider experiments with heavy ions up to Gold in the center of mass energy from 4 to 11 GeV/u and an average luminosity up to 1 · 1027 cm-2s-1 for Au79+. The collisions of polarized deuterons are also foreseen. The facility includes two injector chains, a new superconducting booster synchrotron, the existing 6-AGeV superconducting synchrotron Nuclotron, and a new superconducting collider consisting of two rings, each 503 m in circumference. The booster synchrotron and the NICA collider are based on an iron-dominated “window frame”-type magnet with a hollow superconductor winding analogous to the Nuclotron magnet. The status of the serial production and test of the magnets for the booster synchrotron and the development of the full-size model magnets for the NICA collider is presented. The test results of magnets are discussed. The status of the construction of the facility for serial tests of superconducting magnets for the NICA project is described.

Superferric Quadrupole Magnet With a Pulse Repetition Rate of 10 Hz for High Energy Particle Accelerators

The study of superferric synchrotron magnets with a pulse repetition rate up to 20 Hz is performed at the Laboratory of High Energies of the JINR during the last years. The magnet feature is a low inductance superconducting coil made of a high current hollow cable, cooled with two-phase helium flow at 4.5 K. After the successful tests of fast-cycling 1.4 m model dipoles at the field ramp up to 7 T/s, a proper quadrupole is under design and construction. The new magnet yoke length is about 420 mm and the distance between the pole shoes is 90 mm. The cable comprises 24 wires of 0.73 mm diameter are wound around a copper-nickel tube with an outer diameter of 5 mm. The wire consists of 10374 NbTi filaments of 4.2 mum diameter. It is expected that the new 32 T/m quadrupole magnet will operate at pulse repetition rate up to 10 Hz providing the field gradient ramp of 600 T/m per second. The first tests have been carried out in August 2006. Status of the work and obtained results are presented and discussed.