CS2: The PTB's new primary clock

Bauch, A.; Dorenwendt, K.; Fischer, Bernd; Heindorff, T.; Muller, E. K.; Schröder, R.

doi:10.1109/tim.1987.6312751

Cited by 19 publications

(12 citation statements)

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“…The atomic beam intersects the cavity one half wavelength away from the short magnet. A linear dependence of the microwave field phase on the vertical position of (83 ± 3) µrad mm −1 was found for such a type of cavity in studies performed in a separate frequency standard (see section 5) [14] and of (94 ± 10) µrad mm −1 with CS2 itself [13]. This value, combined with the estimated capability that after a beam reversal the atomic trajectories are the same as before, leads to the respective contributions to the CS2 uncertainty-which actually is the largest of all-as depicted further below in figure 8.…”

Section: Description Of the Construction Principles Common To Cs1 Andmentioning

confidence: 80%

The PTB primary clocks CS1 and CS2

Bauch¹

2005

Metrologia

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The primary clocks CS1 and CS2 have been developed and operated by the Physikalisch-Technische Bundesanstalt, Braunschweig, Germany. By their contributions to the definition of the scale unit of International Atomic Time they have provided access to the realization of the SI second over decades with exceptional accuracy. They have stood out against other primary clocks by the novelty of their design concept, their robustness of construction and last but not the least by their almost continuous operation for many years. Their properties have changed with time, but during the last 7 years their uncertainty, u B , has been estimated as 8 × 10 −15 (CS1) and 12 × 10 −15 (CS2). Comparisons with PTB's cold-atom frequency standard CSF1 (u B = 1 × 10 −15) over 3.5 years revealed that CS2 and CSF1 agreed well within the uncertainty u B (CS2), whereas CS1 frequency deviates slightly more from CSF1 than u B (CS1).

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Section: Description Of the Construction Principles Common To Cs1 Andmentioning

confidence: 80%

The PTB primary clocks CS1 and CS2

Bauch¹

2005

Metrologia

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“…Here it proved as a drawback that in case of the CSX a reversal of the direction of the atomic beam-the traditional method to measure the f in primary clocks [12,15]-could not be made.…”

Section: Fig 2 Normalized Intensity Of Blackbody Radiation Which Ismentioning

confidence: 99%

“…During our experiments, the atomic flux was chosen such that the short-term frequency instability, expressed by the Allan standard deviation s y ͑t͒, was 3.5 3 10 212 ͑͞t͞s͒ 1͞2 . Frequency measurements were made using PTB's primary clock CS2 as a reference [15], and the relative frequency difference y XR : ͓n͑CSX͒ 2 n͑CS2͔͒͞n͑CS2͒ was recorded. Here n͑CS2͒ and n͑CSX͒ are the clock transition frequencies of the CS2 and the CSX, respectively, corrected for all systematic frequency shifts [12,15] except for the CSX cavity phase difference (see below).…”

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confidence: 99%

“…Frequency measurements were made using PTB's primary clock CS2 as a reference [15], and the relative frequency difference y XR : ͓n͑CSX͒ 2 n͑CS2͔͒͞n͑CS2͒ was recorded. Here n͑CS2͒ and n͑CSX͒ are the clock transition frequencies of the CS2 and the CSX, respectively, corrected for all systematic frequency shifts [12,15] except for the CSX cavity phase difference (see below). The combined frequency instability was s y ͑t 1d͒ 18 3 10 215 and s y ͑t 7d͒ 7 3 10 215 during normal CSX operation (data points at T BBR ഠ 300 K in Fig.…”

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Experimental Verification of the Shift of the Cesium Hyperfine Transition Frequency due to Blackbody Radiation

Bauch

Schröder

1997

Phys. Rev. Lett.

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An atomic-beam resonance apparatus has been used to measure the dynamic Stark shift of the groundstate hyperfine transition frequency in cesium ͑ഠ 9.2 GHz͒ due to the electric field of blackbody radiation. The shift was measured as a function of the temperature of heated surfaces surrounding the atomic beam. The observed dependence of the transition frequency on temperature is in good agreement with theoretical predictions. At room temperature, the expected relative frequency shift is 216.9 3 10 215 , whereas the experimental result is 216.6͑2.

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“…The principal error sources are the magnetic field correction and the phase difference between the microwave fields at the two interrogation regions. 18 Recently, Hewlett-Packard introduced their model 5071 cesium standards, with a significantly improved electronics package. 19 This model cesium clock has demonstrated superior performance both in the laboratory 20 and in the field.…”

Section: Terrestrial Clocksmentioning

confidence: 99%

Application of Millisecond Pulsar Timing to the Long-term Stability of Clock Ensembles

Foster

Matsakis

1996

Amazing Light

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Terrestrial timescales show instabilities due to the physical limitations of the atomic clocks. Stricter environmental isolation and increased numbers of improved cesium clocks and cavity-tuned hydrogen masers have resulted in time scales more accurate by a factor of about five. The use of different clock ensembles results in measurable changes in some millisecond pulsar timing data. We investigate the possible application of millisecond pulsars to define a precise long-term time standard and positional reference system in a nearly inertial reference frame. Although possible quantitative contribution of the two longest studied millisecond pulsars to terrestrial timescales appears minimal, they may prove useful as independent standards in identifying error sources that are difficult to detect due to the finite lifetime and common reference frame of terrestrial clocks. New millisecond pulsars, perhaps some with even better timing properties, may be discovered as a result of the current global pulsar search efforts.

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CS2: The PTB's new primary clock

Cited by 19 publications

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The PTB primary clocks CS1 and CS2

The PTB primary clocks CS1 and CS2

Experimental Verification of the Shift of the Cesium Hyperfine Transition Frequency due to Blackbody Radiation

Application of Millisecond Pulsar Timing to the Long-term Stability of Clock Ensembles

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