Hanno Leibrock

Prototype of the Superferric Dipoles for the Super-FRS of the FAIR-Project

The FAIR China Group (FCG), consisting of the Institute of Modern Physics (IMP Lanzhou), the Institute of Plasma Physics (ASIPP, Hefei) and the Institute of Electric Engineering (IEE, Beijing) developed and manufactured in cooperation with GSI, Germany a prototype of a superferric dipole for the Super-Fragment-Separator of the FAIR-project. The dipole magnets of the separator will have a deflection radius of 12.5 m, a field up to 1.6 T, a gap of at least 170 mm and an effective length of more than 2 meters to bend ion beams with a rigidity from 2 T · m up to 20 T · m. The magnets operate at DC mode. These requirements led to a superferric design with a yoke weight of more than 50 tons and a maximum stored energy of more than 400 kJ. The principles of yoke, coil and cryostat construction will be presented. We will also show first results of tests and measurements realized at ASIPP and at IMP.

Magnetic Field Design of the Dipole for Super-FRS at FAIR

The Super-FRS (Super FRagment Separator) is a part of FAIR (Facility for Antiproton and Ion Research), which will be constructed at GSI, Germany by 17 countries. The Super-FRS comprises 24 superferric dipole magnets. The 2D and 3D magnetic field simulations of the prototype magnet are described in this paper. A passive trim slot and four chamfered removable poles are used to satisfy the required field homogeneity which is better than at 1.6 T, 0.8 T and 0.16 T in a wide elliptical useable aperture of 380 mm 140 mm. Measurement results at various field levels are shown in this paper as well. It can be seen from the comparison of calculation and measurement results that the magnetic designs of the magnet fulfils the requirements.

Status of the Superconducting Magnets for FAIR

The Facility for Antiproton and Ion Research is now fast approaching its realization phase. Roughly 800 superconducting magnets are required for the SIS100 and the Super-FRS machines. Given their long lead time of procurement for this large number of items, the SIS100 dipoles series is already ordered with the quadrupole modules following swiftly. The Super-FRS dipole and multiplets are being tendered. In a second realization phase the SIS300 accelerator will be built and placed in the same common tunnel as the SIS100. We report the status of magnet production of the different projects together with the experiences obtained during the manufacturing process of the first SIS100 series dipole.

The Cold Test of Super-FRS Superconducting Dipole Prototype for FAIR Project

Superconducting dipole prototype of the Super-FRS (Super FRagment Separator) for FAIR Project (Facility for antiproton and Ion Research) which is jointly developed by the Institute of Modern Physics (Lanzhou), the Institute of Plasma Physics (Hefei) and the Institute of Electrical Engineering (Beijing), have passed the final magnetic field measurement and low temperature test. The magnetic flux density is up to 1.6 T when the operating current is 232 A, and magnetic field homogeneity meets the calculation result which is ±1 × 10-4. The single ramping tests up to 232 A and 278 A at the rate of 3 A/s, 3 triangular cycles ramping up to 232 A within 120 seconds, and the quench tests at 232 A and 278 A by using the spot heater were done. Some other tests were finished at the same time. All the test results indicate that the superconducting dipole prototype could meet the requirements of FAIR.

Some Superconducting Magnets at IMP

Some superconducting magnets research at IMP (Institute of Modern Physics, CAS, Lanzhou) will be described in this paper. Firstly, a superconducting electron cyclotron resonance ion source (SECRAL) was successfully built to produce intense beams of highly charged heavy ions for Heavy Ion Research Facility in Lanzhou (HIRFL). An innovation design of SECRAL is that the three axial solenoid coils are located inside of a sextupole bore in order to reduce the interaction forces between the sextupole coils and the solenoid coils. For 28 GHz operation, the magnet assembly can produce peak mirror fields on axis of 3.6 T at injection, 2.2 T at extraction, and a radial sextupole field of 2.0 T at plasma chamber wall. Some excellent results of ion beam intensity have been produced and SECRAL has been put into operation to provide highly charged ion beams for HIRFL since May 2007. Secondly, a super-ferric dipole prototype of FAIR Super-FRS is being built by FCG (FAIR China Group) in cooperation with GSI. Its superconducting coils and cryostat is made and tested in the Institute of Plasma Physics (IPP, Hefei), and it more 50 tons laminated yoke was made in IMP. This super-ferric dipole static magnetic field was measured in IMP, it reach to the design requirement, ramping field and other tests will be done in the future. Thirdly, a 3 T superconducting homogenous magnetic field solenoid with a ¿70 mm warm bore has been developed to calibrate Hall sensor, some testing results is reported. And a penning trap system called LPT (Lanzhou Penning Trap) is now being developed for precise mass measurements.

Quench Measurement on SIS100 Dipole Model

The international FAIR project planned next to G.S.I. (Germany) will lead to the construction of two superconducting synchrotrons (SIS100 and SIS300). This article reports on the quench calculations and measurements performed on one short SIS100 dipole model (1.4 m), the first to be tested at the FAIR prototype test facility. Quench propagation velocities and time to reach the 0.2 V quench threshold were measured in the bus bars and compared to computed values. The hotspot temperature was measured for different Miits (integral of I2 .dt) values at 6 and 8 kA and compared to temperatures computed with the Miits equation. This article also reports the use of one inductive spot heater.

Optimization of the Sextupole Magnets With Trim Coils for the Collector Ring of the FAIR Project

The collector ring (CR) is a part of the challenging international project facility for antiproton and ion research started in Darmstadt, Germany. The ion optics of the CR includes sextupole magnets with embedded dipole correction coils. To fulfill the requirements of the field quality in the magnet aperture, it is necessary to find an optimal pole tip shape as well as an optimal configuration of the coil system. We used a specially developed optimization procedure for designing the magnet cross section. This procedure consists of two steps. The first one is based on a representation of the pole border line by a superposition of hyperbolic functions corresponding to different Fourier components of the magnetic field expansion. The optimization procedure based on the Newton-Raphson descend algorithm minimizes amplitudes of the undesired field harmonics. At the second step of the magnet design procedure, the parameters of the dipole winding are optimized to provide the required field characteristics in the magnet aperture.

Conceptual Design of Cryogenic Facilities for Super-FRS of FAIR

We present the concept design of the cryogenic feedbox for the superconducting dipole and quadrupole/multi-pole magnets of the Super-FRS (FRagment Separator) project. It also includes the warm gas control and management, the instrumentation and the control logic related with different operation modes of the magnet cooling. As one of the most important trip scenarios for cryogenic facilities, the over pressure in the magnet helium vessel caused by quench has been simulated for a prototype dipole. For safety reason, the safety relief valve and its sizing have also been taken into account.

Fast Ramped Quadrupoles for the Transition Jump Scheme of the SIS100 Synchrotron of the FAIR Project

A gamma transition jump scheme has been developed for the heavy ion synchrotron SIS100 to modify the gamma transition during the acceleration of protons in such a way that the speed at which the relativistic gamma of the beam crosses the transition gamma is increased by two orders of magnitude. The transition crossing will be at gamma = 8.9, which corresponds to a kinetic proton energy of 7.4 GeV and a beam rigidity of about 28 Tm. The scheme employs fast-ramped quadrupoles with a ramping time of 0.5 ms from the maximum integral gradient of 0.4 T to the minimum integral gradient of minus 0.4 T. Each of the 12 fast ramped quadrupoles is embedded inside the cryostats of the so-called quadrupole doublet modules together with two main superconducting quadrupoles and one corrector magnet. The vacuum chamber, coils, and iron yoke are cooled with liquid helium. Nevertheless, the coils are made of standard copper tubes with a residual resistivity ratio of approximately 100 to avoid quench problems due to the fast ramping. The requirements and design of these normal conducting magnets inside the cryogenic environment are described.

Solenoid Development for an Emittance Transfer Experiment With a Design Environment System

Various solenoids must be developed for different machines of the FAIR-Project. A solenoid design environment (SDE) has been developed to reduce expenditure of design time and work. The design environment is based on an Opera-2d input text file. Most significant physical and technical parameters of a solenoid are considered. Due to the axial symmetry, a two-dimensional solenoid model describes well the main characteristics of a real magnet. The first use of the SDE was the design of a solenoid for an emittance transfer experiment at GSI. The 36 cm long magnet creates a flux density of 1 Tesla at the center. The coil of the solenoid is separated in two halves to allow placing a movable stripping foil on the beam axis. Nevertheless, the magnet design avoids a local flux minimum in the center, since it might act as a trap of electrons. Creating a SDE and a solenoid with this tool takes a little more manpower than designing one solenoid without environment system. But in the future the SDE will help to decrease development time significantly.