Magnetic Measurement Documentation

Current status

This page is dedicated to document the current stage of the measurement of the multipoles using the combination method. The basis of this approach is documented in P. Schnizer et al: "Theory and application of plane elliptic multipoles for static magnetic fields", NIMA, Volume 607, Issue 3, 21 August 2009, Pages 505–516 doi:10.1016/j.nima.2009.06.007.

Here all further details on the data evaluation are collected, in particular

• the coordinate systems of the different devices
• and the involved data treatment.

Coordinate systems

All coordinate systems shall be right hand coordinate systems. This is a prerequisite as Maxwell's equation contain rotors. Further the Lorentz force uses the cross product. Convention defines it for right hand coordinate systems.

Coordinate system of the machine

Coordinate system of the mole

Coordinate system of the anticryostat

Mounting of the Dipole magnet on the test bench

and its impact on further calculations

Multipole calculations

The measurement program steers the different devices. It stores in the files:

• the monitored current. These current values are read out after each single measurement has been executed.
• the angle and the read out flux of the absolute and the compensated channel. The angle must start at 0 degree and must also include the angle 360 degree. This is required so that the drift can be corrected.

Documentation of the analysis

The different measurements are combined in a separate software application. This software application

• reads the fluxes as measured by the coil probes
• calculates the multipoles from the fluxes obtained by the rotating coil probe
• and rotates these by 180 degrees. Thus the flags of the multipoles are reverted as: C'_n = C_n exp(i * n * π)

Missing: Link to the application

-- PierreSchnizer - 07 Jan 2016