Undergraduate Research at Jefferson Lab

Error Analysis of Emittance Measurements

Student: Deepsana Shahi

School: Adelphi University

Mentored By: Todd Satogata

Errors in measured emittance and Twiss parameters are computed from the errors in the measured beam sizes, which describes an area of the beam and beam sizes, respectively. When the electron beam moves through quadrupole magnets, giving transverse coordinates in the direction of the beam's motion, the beam profile measurements are collected by measuring the harp signal intensity and position as its wire passes through the beam using a wire scanner (or harp). The Gaussian distribution of particles in phase space (x, x') fits the beam intensity and measures the square beam sizes by using the fit parameters. The measurements in emittance and Twiss parameters are computed along with the errors by analyzing the beam size data based on transverse beam profile measurements. By propagating measurement errors in the square beam sizes, the error bars for emittance measurements and Twiss parameters are calculated. The emittance measurement values range between 7.08×10^-10 and 2.69×10^-9 [m] with 10^-11 [m] error.