PRELIMINARY MEASUREMENT OF THE J equals 0 TO J equals 2 FINE STRUCTURE INTERVAL IN THE 3**3P STATE OF HELIUM.

Time resolved measurements are made of the level crossing signal from the J equals M equals 2, and the J equals M equals 0 sublevels of the 3**3P state of He near 2277 gauss. A thermal beam of He 2**3S metastables is excited by a pulse of 3889 A dye laser light and a temporal slice of the fluorescence at 90 degree to the field is recorded by fast electronics as a function of field. This experiment has been carefully designed to minimize the effects of very many possible systematic errors. A S/N of about 15 in each of about 100 data sets is obtained (approx. 1 hour run time). The result has a statistical standard error of 1. 4 ppm and a systematic uncertainty of about 1. 4 ppm, resulting in a net uncertainty of 2 ppm. The distribution of the results is approximately a Gaussian of width 14 ppm and the average, corrected for field inhomogeneity, is 9695. 013 kHz (NMR, H//20).