Magnetic Measurements of a Third Harmonic Table-Top Undulator for Free Electron Lasers

We describe the measurement studies of a third harmonic undulator. The harmonic undulator is fabricated by placing shims at suitable locations along the length of a table-top six-period planar undulator. The undulator field is measured with a Hall probe and pulsed wire bench. The pulsed wire data show good agreement with the Hall probe data.