Systematic Uncertainty Evaluation of the Cesium Fountain Primary Frequency Standard at NPL India

Acharya, Aishik; Vattikonda, Bharath; Arora, Poonam; Yadav, Sneha; Agarwal, Ashish; Gupta, Amitava Sen

doi:10.1007/s12647-016-0190-4

Cited by 19 publications

(6 citation statements)

References 24 publications

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“…Currently, the scale unit of International Atomic Time (TAI) is almost exclusively based on monthly frequency calibration reports by several fountain clocks serving as primary frequency standards (PFS) [2]. During the past five years, eleven primary caesium fountain clocks from eight different metrology institutes in Europe [3][4][5][6][7][8], the US [9][10][11] and Asia [12,13] contributed to TAI. One of these fountains additionally operated as a dual fountain, simultaneously using caesium and rubidium atoms [14], providing additional TAI calibrations with a secondary representation of the SI second.…”

Section: Introductionmentioning

confidence: 99%

Advances in the accuracy, stability, and reliability of the PTB primary fountain clocks

et al. 2018

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Improvements of the systematic uncertainty, frequency instability, and long-term reliability of the two caesium fountain primary frequency standards CSF1 and CSF2 at PTB (Physikalisch-Technische Bundesanstalt) are described. We have further investigated many of the systematic effects and made a number of modifications of the fountains. With an optically stabilized microwave oscillator, the quantum projection noise limited frequency instabilities are improved to 7.2 × 10 −14 (τ /1 s) −1/2 for CSF1 and 2.5 × 10 −14 (τ /1 s) −1/2 for CSF2 at high atom density. The systematic uncertainties of CSF1 and CSF2 are reduced to 2.74 × 10 −16 and 1.71 × 10 −16 , respectively. Both fountain clocks regularly calibrate the scale unit of International Atomic Time (TAI) and the local realization of Coordinated Universal Time, UTC(PTB), and serve as references to measure the frequencies of local and remote optical frequency standards.

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Section: Introductionmentioning

confidence: 99%

Advances in the accuracy, stability, and reliability of the PTB primary fountain clocks

et al. 2018

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“…Among them, the largest contributions to the total uncertainty are collisional shift and microwave-power related frequency shift. CsF2 [20] CsF2 [95] FO2 [96] CsF2 [97] CsFO2 [21] F2 [98] NIM5 [99] CsF1 [100] FOC2 [97]…”

Section: Fountain Clock Evaluationsmentioning

confidence: 99%

Cold atom clocks and their applications in precision measurements*

Dai¹,

Zheng²,

Liu³

et al. 2021

Chinese Phys. B

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Cold atom clocks have made remarkable progresses in the last two decades and played critical roles in precision measurements. Primary Cs fountain frequency standards have achieved a total uncertainty of a few parts in 1016, and the best optical clock has reached a type B uncertainty below 10−18. Besides applications in the metrology, navigation, etc., ultra-stable and ultra-accurate atomic clocks have also become powerful tools in the basic scientific investigations. In this paper, we focus on the recent developments in the high-performance cold atomic clocks which can be used as frequency standards to calibrate atomic time scales. The basic principles, performances, and limitations of fountain clocks and optical clocks based on signal trapped ion or neutral atoms are summarized. Their applications in metrology and other areas are briefly introduced.

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“…Calibration of precision clocks, oscillators, GNSS receivers, stop watches, etc., is also provided. In addition, the NPL is working toward development of state-of-the-art ultramodern atomic clocks and dissemination techniques for improving time keeping and dissemination capabilities [86,87].…”

Section: Status Of Unit Of Time (Second)mentioning

confidence: 99%

Evolution of Measurement System and SI Units in India

Rab

Yadav

Garg

et al. 2020

MAPAN

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The paper presents a terse review on the evolution of measurement system and International System of Units (SI) in India, the methodology followed to realize the measurement units and the present state of the art in realizing of 7 base units. The measurement systems evolved, developed and used during several ancient historical periods, Indus valley to Vedic period to existing SI system of modern era, are discussed. The major activities carried out during ancient times were primarily based on the units of mass, length and time. The current system has been established and adopted to realize SI units through the fundamental constants, invariant of time and space, which has replaced the dependence on artifacts. The new era of SI system based on quantum metrology has established linkages of all the 7 base units to fundamental constants. The aim of the study is to present the major events, activities and developments carried out in India pertaining to the evolution of SI units. The SI system at the top of traceability chain and heart of metrology and measurement system, it is of utmost important to understand, how the SI system is evolved historically: It becomes further inevitable when India is aiming for AtmaNirbhar Bharat (Self-Reliant India) for augmenting the industrial growth of Indian economy, wherein strengthening the national quality infrastructure for enhancing trade and commerce shall be indispensable and unbroken chain of measurement traceability through new SI system would play a major role. The present review would provide a concise report on these developments, starting from Indus valley period to existing era.

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Systematic Uncertainty Evaluation of the Cesium Fountain Primary Frequency Standard at NPL India

Cited by 19 publications

References 24 publications

Advances in the accuracy, stability, and reliability of the PTB primary fountain clocks

Advances in the accuracy, stability, and reliability of the PTB primary fountain clocks

Cold atom clocks and their applications in precision measurements*

Evolution of Measurement System and SI Units in India

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