Beam Line Magnet Information

Information on magnets used in the PS & SPS Secondary beam lines.

Magnet Characteristics

Information and characteristics of the mangets is available in the 'Magnets Kit''' compilation for:

• PS ( dipoles, quads)
• SPS.

MBN Magnets

The MBN magnets are the main bending dipoles for the SPS North Area beam lines designed in the early 70's. They are 6m long laminated magnets with a peak field of about 2 Tesla. The main characteristics can be found in the "magnets kit". The latest measurement campaign for the MBN magnets was in 2002 for the needs of the ATLAS Liquid Argon test beam in 2002; the results summarized in the EDMS document 626771.

The MBN magnets form the momentum defining spectrometer of the secondary beams of the North Area. In order to guarantee a good reproducibility and linearity of the beam, a proper demagnetization (de-Gauss) procedure has to be made each time the energy of the beam changes. Measurements showed that a 5-cycle unipolar exitation of the magnet up to its saturation leaves a remanent field close to 1 Gauss which is very good for most users 1. Such a procedure is now implemented in the CESAR control software of the beam lines.

MBP Magnets

The MBP magnets are large gap uniform field dipole magnets used already since the 70s in the PS experimental area secondary beams. They exist in two variants having the same cross-section of the core and the coils and different length: 1m (MBPS) and 2m (MBPL). There are also two families depending on the shape of the poles: straight or tapered which offer higher magnetic field but with limited aperture. The gap height of the magnets can be varied from 11 to 20cm.

The magnetic properties of the MBP magnets are well known . Last time they were measured in 1991 for the NA44 experiment J.Leroux, NA44 Note-58 19.08.1991. The BdL response vs the supplied current is typically parameterezed using a multi-order polynomial. Bdl parameterizations for the most commonly used configurations:

• MBPL magnets: data {straight poles, tapered poles}, fit results)
• MBPS magnets: data

-- BrunoChauchaix - 22 Jan 2009