Chapter 41 Demonstration of a Physics Package with High SNR for Rubidium Atomic Frequency Standards

摘要

The frequency stability of a rubidium atomic frequency standard (RAFS) depends mainly on the signal to noise ratio (SNR) of atomic discrimination signal provided by the physics package. In order to improve further the frequency stability of our RAFS, a new physics package with high SNR was designed recently. The physics package was designed based on an improved slotted tube cavity. Compared with our previous design, the new cavity has more uniform magnetic line distribution and larger size, so that a larger resonance cell can be used. In the design the separated filter technique (SFT) was used. A Helmholtz coil was substituted for a solenoid one to create a more uniform C field. At present a prototype of the physics package has been made. A preliminary test has been performed, and a short term frequency stability of 6 × 10~(-13)/1 s was achieved. This result indicates that the SNR of the physics package could meet the requirement for building a RAFS with frequency stability better than 1 × 10~(-12)/τ~(1/2).