Helmholtz coil

The next is to calibrate the gain, using a pair of Helmholtz coils.

Helmholtz coil - a device for producing a region of nearly uniform magnetic field.

If the intention is to make serious measurements calibration with a Helmholtz coil will be required.

Another design is a Helmholtz coil layout but with the current in one of the coils reversed.

The magnetic excitation field is made by a pair of circular Helmholtz coils above and below the disk.

Place the sensor in the centre of the Helmholtz coils with one pickup winding aligned to pick up maximum flux.

Solenoids and Helmholtz coils are types of coils that can be used for this purpose.

For a pair of planar loops forming a Helmholtz coil, magnetic field lines will be approximately parallel in their center.

A pair of Helmholtz coils produces a uniform and measurable magnetic field at right angles to the electron beam.

In a Helmholtz coil, a point halfway between the two loops has an x value equal to R/2, so let's perform that substitution:

In 1934 Braunbeck developed the Braunbek coil, a modified Helmholtz coil.

By measuring the accelerating potential (volts), the current (amps) to the Helmholtz coils, and the radius of the electron beam, e/m can be calculated.

Monitor the appropriate amplifier test point with a voltmeter or calibrated oscilloscope and rotate the Helmholtz coils and sensor to give zero volts.

In some applications, a Helmholtz coil is used to cancel out the Earth's magnetic field, producing a region with a magnetic field intensity much closer to zero.

In 1929 he developed the Fanselau coil, a modified version of the Helmholtz coil, which uses a special arrangement of coils to improve the homogeneity of the generated magnetic field.

James Clerk Maxwell showed in 1873 that a third larger-diameter coil located midway between the two Helmholtz coils can reduce the variance of the field on the axis to zero up to the sixth derivative of position.

A Maxwell coil is an improvement of a Helmholtz coil: in operation it provides an even more uniform magnetic field (than a Helmholtz coil), but at the expense of more material and complexity.

Two years later, in 1907, P.D. Innes experimented with a Röntgen tube, Helmholtz coils, a magnetic field hemisphere (electron energy analyzer) and photographic plates to record broad bands of emitted electrons as a function of velocity, in effect recording the first XPS spectrum.