John Gideon Hartnett

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This paper reports implementation and operation of a frequency synthesizer based on a cryocooled cryogenic Sapphire oscillator (cryoCSO) for the Cesium atomic fountain clock developing at KRISS, KRISS-Fl(Cs). With use of this highly stable local oscillator, the short-term stability of KRISS-F1(Cs) was greatly improved and reaches the quantum projection(More)
A Fourier analysis on galaxy number counts from redshift data of both the Sloan Digital Sky Survey and the 2dF Galaxy Redshift Survey indicates that galaxies have preferred periodic redshift spacings of ∆z = 0.0102, 0.0246, and 0.0448 in the SDSS and strong agreement with the results from the 2dF GRS. The redshift spacings are confirmed by the mass density(More)
We operate an atomic fountain clock KRISS-F1 using a laser system based on a DBR (Distributed Bragg Reflector) laser. We have found that there is no major difference in the fountain performance between laser systems with an ECDL (Extended-Cavity Diode Laser) and the DBR laser, even though spectral properties of the DBR is worse than that of ECDL. Moreover,(More)
In this paper, we report on the implementation and stability analysis of a drift-compensated frequency synthesizer from a cryogenic sapphire oscillator (CSO) designed for a Cs/Rb atomic fountain clock. The synthesizer has two microwave outputs of 7 and 9 GHz for Rb and Cs atom interrogation, respectively. The short-term stability of these microwave signals,(More)
We report on a robust distributed Bragg reflector (DBR) laser system for an atomic fountain clock. To confirm the performance of a DBR laser, the short-term stability of an atomic fountain clock, KRISS-F1, is measured with both DBR laser and an extended-cavity diode laser (ECDL) as a master laser in the fountain laser system. The short-term stability of the(More)
A Fourier analysis on galaxy number counts from redshift data of both the Sloan Digital Sky Survey and the 2dF Galaxy Redshift Survey has been carried out. The results indicate that galaxies have preferred periodic redshifts. Application of the Hubble law results in galaxies preferentially located on concentric shells with periodic spacings. This analysis(More)
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