Magnetization, Critical Current, and Injection Field Harmonics in Superconducting Accelerator Magnets

Compensation of Magnetization Effects in Superconducting Accelerator Magnets

Magnetization effects in the coils of superconducting accelerator magnets deteriorate the field quality at injection field level. The CERN field computation program ROXIE has recently been extended to calculate the persistent currents using a semi-analytical hysteresis model for hard superconductors. The model is combined with the coupling method of finiteand boundary-elements for the calculati...

State-of-the Art Superconducting Accelerator Magnets

With the LHC the technology of NbTi-based accelerator magnets has been pushed to the limit. By operating in superfluid helium, magnetic fields in excess of 10 T have been reached in various one meter-long model magnets while full scale magnets, 15 meter-long dipoles, have demonstrated possibility of safe operation in the 8.3–9 tesla range, with the necessary, very tight, field accuracy. The pap...

Change in Field Harmonics after Quench and Thermal Cycles in Superconducting Magnets*

A change in field harmonics after quench and thermal cycles has been observed in superconducting magnets for the Relativistic Heavy Ion Collider (RHIC). This paper presents the results of a systematic investigation of this effect in a number of RHIC dipole and quadrupole magnets. These changes in field harmonics may limit the ultimate field quality and its reproducibility in superconducting mag...

RHIC IR Quadrupoles and Field Quality State of the Art in Superconducting Accelerator Magnets

The interaction region (IR) quadrupoles [1] for the Relativistic Heavy Ion Collider (RHIC) [2] are the best field quality superconducting magnets ever built for any major accelerator. This field quality is primarily achieved with the help of eight tuning shims [3] that remove the residual errors from a magnet after it is built and tested. These shims overcome the limitations from the typical to...

Superconductor Magnetization Modeling for the Numerical Calculation of Field Errors in Accelerator Magnets