Ammonia Maser on the 3, 2 Line as a Frequency Standard I

The frequency of a maser on the J =3, K =2 line of N 14 H 3 was compared with the multiplied frequency from a 100 kc standard of one of quartz clocks. The measured fluctuation was much larger than that of the maser itself because of small phase fluctuations in the 100 kc signal. When the maser was tuned by a magnetic perturbation method, the frequency drift and the error in resetting could be kept within several parts in 10 11 . The observed frequency shift with the focuser voltage was 7×10 -11 /kV at a source flux of about 7×10 17 molecules per second. The frequency-shift with the increase of source flux by 10 percent was about 1×10 -11 . The stability and reproducibility are discussed in comparison with the hydrogen maser. It is shown that the ammonia maser will reach an accuracy of 10 -13 , when an automatically balanced double beam is used.