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Desy Summerstudent Program 2004. Calibration of a 3D Hall probe for magnetic field investigations in undalators and wigglers. Outline: Motivation Experimental procedure Magnetic field characterisation Hall probe calibration Conclusion. Front view. Motivation. B x. B z.
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Desy Summerstudent Program 2004 Calibration of a 3D Hall probe for magnetic field investigations in undalators and wigglers. • Outline: • Motivation • Experimental procedure • Magnetic field characterisation • Hall probe calibration • Conclusion Sebastien Couet
Front view Motivation Bx Bz Schematic wiggler • Electron remains in the ring for a long time. • They have to stay on track! We have to take great care of the influence of the magnetic field in the wiggler. Sebastien Couet
Motivation Use of a Hall probe: • Gives a voltage function of the magnetic field. • Point like measurement. • Fast response. Problem: • We need a precision of 10-6 T. • Apparition of non linear effect. Sebastien Couet
Procedure Given Hall potentials: • Procedure: • Characterisation of the field • - coil(horizontal) • - dipole magnet(vertical) • Determination of c1 • Determination of a1, a2, c2 • Determination of cross sensitive parameter c3 Sebastien Couet
Magnetic field characterisation Use of a NMR probe: Advantages: - Gives a very precise absolute value of the field. Disadvantages: - No direction information. - Need homogenous field(not point like). Sebastien Couet
Magnetic field characterisation In the coil: (horizontal field) Sebastien Couet
Bx BNMR Bz Magnetic Field Characterisation In the dipole magnet: (Vertical + horizontal) Sebastien Couet
Magnetic field characterisation Finally, we get the evolution of the slope coefficient: Conclusion. Field determination is possible but: - use of bigger coil - need of stronger horizontal field To get more accurate results. Sebastien Couet
Hall probe calibration Offset measurement: Use of a zero gauss chamber. Temperature dependence: Dependence: 10-4 V/ºC Sebastien Couet
Hall probe calibration Horizontal component: Need a very precise alignment. C1=5.10134 0.005 V/T Sebastien Couet
Conclusion Determination of a two component magnetic field is possible with NMR. Need: - Better homogeneity - bigger horizontal field Bigger coil. Calibration of a 3D hall probe. - need to improve the precision of the measurement. Sebastien Couet