BNL, Upton, New York, USA
The quadrupole scan is commonly used for measurement of beam emittance. The found dependence of the beam size vs. quadrupole strength is fitted with parabola, which coefficients are used for emittance calculations. The measurement errors can cause substantial variations in the emittance value. Sometimes the fitted parabola has negative minimum value, making impossible emittance calculation. We propose more robust data processing using weighted fit for parabola or modifying the quadrupole scan procedure. The experimental results are presented.
