Transverse emittance measurement for the heavy ion medical machine cyclotron

The transverse emittance of the extracted beam from the heavy ion medical machine cyclotron is measured and then optimized for injection into the synchrotron. For the purposes of cross-validation, three methods, i.e., slit-grid, Q-scan, and 3-grid, are used to measure the emittance. In the slit-grid technique, an automatic selection of the region of interest is adopted to isolate the major noise from the beam phase space, which is an improvement over the traditional technique. After iterating over the contour level, an unbiased measurement of the emittance can be obtained. An improvement in the thin lens technique is implemented in the Q-scan method. The results of these measurements are presented.