Beam test of improved magnetic-scan emittance monitor

In a radioactive ion beam linac at KEK-Tanashi, we have replaced one of double-slit type emittance monitors with a magnetic-scan emittance monitor for ion beams with charge-to-mass ratio greater than 1/l2. The monitor comprises two slits, a magnet located between the slits and a charge collecting plate located after rear slit. The emittance is scanned by sweeping magnetic field instead of moving rear slit. The emittance measured by magnetic-scan type was nearly same as that by double-slit type, and the measurement speed of the magnetic-scan type was 7-times faster than that of the double-slit type. (author)