Experience with magnetic shielding of a large scale accelerator

Abstract

It is not unusual to place multiple accelerators in a common enclosure to save on civil construction costs. This often complicates operations, especially if accelerators are affecting each other. At Fermilab, the influence of a rapidly cycling Main Injector (MI) synchrotron on an antiproton storage ring (Recycler), placed in a common tunnel, was initially found to be unacceptable for a reliable operation of the Recycler. Initial closed orbit excursions in the Recycler ring during the MI ramp were in excess of 5 mm (rms). This paper describes a shielding technique, used to reduce these orbit excursions by a factor of five.

Design of a Linear Variable Differential Transformer With High Rejection to External Interfering Magnetic Field

“…A maximum interfering magnetic field of 800 A/m (1 mT of magnetic flux density in air) has been considered. This represents a reasonable value, extrapolated from examples of critical installations [7], [13]. Anyway, the design guidelines discussed here can be easily applied to stronger interference cases.…”

Measurements of sub-nT dynamic magnetic field shielding with soft iron and mu-metal for use in linear colliders

“…Magnetic shields have already been used at different large-scale accelerator facilities, e.g. Brookhaven National Laboratory [28,29] and Fermilab [25,30]. This section describes various considerations for using the above materials to shield magnetic fields in linear colliders and the factors that affect performance.…”

“…A similar methodology to [25] was used in this work to measure the shielding performance of the soft iron and mu-metal cylinder. A three-axis Bartington Mag-13 fluxgate magnetometer [26] was used in the measurements.…”

Design of a neutrino source based on beta beams

“…Unfortunately, it is not possible to use such a system for the decay ring. Electron cooling would require an electron beam of more than 50 MeV [103] and electron capture would introduce a severe loss mechanism. Stochastic cooling [101] rates at the bunch intensities envisaged are orders of magnitude too slow and laserion cooling is neither possible because the ions are necessarily fully stripped and also there is no significant synchrotron radiation to provide damping.…”