An Alternative to Classical Real-time Magnetic Field Measurements using a Magnet Model

Longitudinal and transverse beam control in circular accelerators depends critically on a reliable real-time knowledge of the magnetic bending field. Traditionally this is achieved with a long-measurement coil placed in a reference magnet. In the CERN PS Booster, such a measurement generates a 1 Gauss step-size train with an absolute precision of 0.1%. Modern magnet control can be done with a precision of 0.01%. Consequently, a synthesised magnetic field train based on a reliable magnet model could potentially yield a 10 times better result. The PSB will become a part of the injector chain for the future Large Hadron Collider (LHC). Therefore the main power supply of the PSB has been upgraded to full cycle control. This has made it possible to follow the entire magnetic cycle with a refined model, and to synthesise a real-time magnetic field train from a newly developed programmable pulse generator. We will discuss the general design concepts and the first results.