Pierre Schnizer

Fast Ramped Superferric Prototypes and Conclusions for the Final Design of the SIS 100 Main Magnets

The 100 Tm synchrotron SIS 100 is the core component of the Facility of Antiproton and Ion Research (FAIR). An intensive R&D allowed reducing the AC losses considerably as well as improving the field quality. High priority was also given to the investigation of the mechanical stability of the superconducting coil to guarantee a long term life time of at least 20 years with more than 2middot108 operation cycles and to position the cable windings precisely. Prototype magnets were built last year with the first dipole magnet completed by Babcock Noell GmbH and currently being under preparation for intensive testing. After a brief description of the main R&D results the key features of three full scale dipoles and a quadrupole prototype are given as well as the expected heat load at 4 K for the 3 m long dipoles for the most important operation modes requested for the SIS100 accelerator. During prototyping additional, more intensive operation cycles were requested by beam dynamics and more cooling power by the vacuum requirements. The consequences for the cooling stability of the dipoles were estimated and preliminary tested on a hydraulic equivalent magnet system and will be verified by the upcoming measurements of the full size models. Necessary modifications for the series production are discussed and the actual chosen SIS100 dipole design fulfilling also the additional operation requirements is outlined.

Magnetic Field Analysis for Superferric Accelerator Magnets Using Elliptic Multipoles and Its Advantages

The Facility for Antiproton and Ion Research (FAIR) will build a set of accelerators and storage rings at the Gesellschaft fur Schwerionforschung (GSI). Nearly all of them transport beams of elliptical shape (SIS 100, CR, NESR, RESR, SuperFRS). Magnetic field calculations as well as magnetic measurements provide precise field information, which is used to improve the properties of the machines using numerical simulations. In this report we develop elliptical multipoles fulfilling the Laplace equation which enable us to describe the field within the whole aperture consistently. Further we show how circular multipoles valid within the elliptic aperture can be derived. We illustrate the advantage of this data representation on the FEM calculations performed during the SIS 100 R&D along with an approach to measure such fields using rotating coils and estimate the influence of measurement artifacts.

Superconducting SIS100 Prototype Magnets Test Results and Final Design Issues

The SIS 100 synchrotron is based on Nuclotron type superconducting magnets. These are operated with 4 T/s up to a maximum field of 2 Tesla (dipoles). Based on the experience of the R&D period three full scale dipoles as well as one quadrupole were built. The first dipole was tested intensively this year. We present the operation performance of the first magnet next to the AC losses and apply a concise description of the magnetic field within the complete elliptical beam pipe. We analyse the static and dynamic field quality of the dipoles and compare them to the calculated ones. These test results allow us describing the parameters of the final dipole design for the machine and the field distortions the vacuum chamber creates along with investigations to reduce these artefacts. Based on our preliminary theoretical R&D and the recent measurement results we conclude on the expected operation parameters of an optimized curved dipole with a high current single layer coil and we describe the actual work topics for this magnet.

Status of the SC Magnets for the SIS100 Synchrotron and the NICA Project

The upcoming machines, the SIS100 accelerator and the NICA booster and collider are a direct offspring of the successful NUCLOTRON magnet concept. SIS100 is now being realized with the dipoles ordered. NICA is in its R&D stage with the first prototype magnets built. The experience gained in the GSI-JINR collaboration dedicated to improving the magnets during the last decade of R&D led now to the common agreement to realize the magnet production and testing in a cooperation for both projects. We describe the parameters, the optimization and tradeoffs made for these magnets and outline the differences. The status of the different magnets next to first results obtained on model or prototype magnets are given. Special attention is given to the advantages of cooling the superconducting magnets with a forced two-phase Helium flow.

Design and Test Status of the Fast Ramped Superconducting SIS100 Dipole Magnet for FAIR

The SIS 100 will be the worlds second fast ramped synchrotron for heavy ion research using superconducting magnets. We summarize the experimental results obtained on two full size model magnets and present the design choices made for the SIS100 dipole. The main design components of the magnet are outlined. Special attention is given to an optimal adjustment of the following topics crucial for reliable and effective operation of the magnets: mechanical stability of the coil windings, magnetic steel, field design, temperature field, AC losses and the vacuum chamber. We conclude that the present dipole design principles are consolidated and are close to series production.

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.

Mole for Measuring SIS100 Magnets Commissioning and First Test Results

The SIS100 synchrotron utilizes fast ramped superconducting magnets operated with a frequency of 1 Hz. The beam pipe is of elliptic aperture and the dipole magnets are curved. Therefore, elliptic and toroidal multipoles were developed which allow describing the field concisely within the whole aperture. A mole (i.e., a measurement system based on a rotating coil probe with all auxiliary components operating within the magnets field) was developed able to sustain ramp rates of up to 4 T/s. It was tested in the field of a conventional magnet and in the first SIS100 superconducting prototype magnet. We recall general design issues of the mole and describe their advantages. We present the first measurements of the mole on the SIS100 prototype and compare them to the results obtained with an independent system. We outline how the rotating coil probe measurements have to be interpreted in the curved magnet using toroidal multipoles, and possible further improvements of the system.

Numerical Analysis of the Operation Parameters of Fast Cycling Superconducting Magnets

The 100 Tm heavy ion synchrotron SIS 100 is the core component of the Facility of Antiproton and Ion Research (FAIR). Prototype magnets were built last year with the first full scale dipole magnet completed and tested. Thorough R&D resulted in FEM models which allow calculating the magnetic field of the magnet during static and dynamic mode. We illustrate the R&D steps required for the FEM calculation. We illustrate its accuracy and describe the expected field quality and dissipated power.

Testing of the Superconducting Magnets for the FAIR Project

The Facility for Antiproton and Ion Research (FAIR) is currently being constructed at GSI Darmstadt. Around 500 superconducting magnets are being procured for the heavy ion synchrotron SIS100, and around 180 are being procured for the Super Fragment Separator (Super-FRS). All these magnets have to be tested at cryogenic temperature in order to verify and guarantee their performances before they are installed in the tunnel. Test stations, measurement equipment, and the required infrastructure are being built up at the host laboratory and, due to the large number of magnets and testing requirements, at CERN and JINR. We report on the plans, testing strategy, developments, and, particularly, the status of preparations for testing of the SIS100 dipoles at GSI.

Fast-Ramped Superconducting Magnets for FAIR Production Status and First Test Results

The SIS100 synchrotron for heavy ion research is based on fast-ramped superconducting magnets. These superferric magnets are being designed, built, and tested. The first 3-m-long series dipole (maximum field of 1.9 T; ramp rate of 4 T/s) has been built. We present the test results obtained (quench training, magnetic field, ac loss, and repetition rate) and compare them with the predicted values and the required operation parameters.