October 16, 1997

Measurement of the beam emittance was carried out at the beamline BL-27 using visible synchrotron light (0:30-10:30 PM).

Tuning on the beam orbit was carried out during 10:30-11:20 PM.

Vacuum conditioning resumed after 11:20 PM with beam currents of 470-500 mA.

Maintenance work for the linac was also carried out (1:00-5:00 PM).

An integrated current of 7.65 A*hrs was gained from 9:02 AM (Oct. 15) and 9:22 AM (Oct. 16). Average beam current was 314 mA.

Precise measurement of beam emittance using visible synchrotron light.

A precise measurement of the beam size was carried out by detecting visible synchrotron light. In order to measure the beam size very accurately, an adaptive optics system was used for the measurement. This is the first application of the adaptive optics system for the measurement of electron beam sizes.

From the measured horizontal and vertical beam sizes of 461 microns (horizontal) and 194 microns (vertical), which were obtained at low beam currents, one can obtain the horizontal and vertical beam emittances of 136 nm*rad and 1.23 nm*rad, respectively. (Note that we are at present operating the PF ring under medium emittance optics, and the new low-emittance optics will be studied afterward.)

(Note) By using measured betatron functions, the emittance values were corrected in November 4.

Beam current and beam lifetime in the daytime.
Measurement of the beam emittance is under way.

Progress of vacuum conditioning by the storage ring operations.

The product of the beam current and beam lifetime (red dots) grows faborably as the integrated stored current increases. Average vacuum pressures, which are divided by the beam current, are also plotted.