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A Low-Cost Instrument for the Accurate Measurement of Resonances in Microwave Cavities
No full textSince vector network analysis became available, it
demonstrated its accuracy and versatility in a variety of applications,
including the accurate measurement of resonances in
microwave cavities. Unfortunately, the high cost and bulkiness
of vector network analyzers (VNAs) set a limit to their applicability.
This paper presents and discusses the design and the
initial performance tests of a simplified instrument which may
represent a valid alternative to VNAs in those applications where
the high quality factors of a microwave resonator have to be determined
with comparable accuracy but at low cost, allowing field
portability and the embedment in a more complex measurement
system. Triggered by the recent development of quasi-spherical
microwave resonators and their successful utilization in gas
metrology, we choose the extremely precise measurement of their
eigenfrequencies as a suitable test bench to validate the specifications
and assess the performance of the proposed instrument
Summary of achievements of the European Metrology Research Programme Project ‘‘Implementing the new Kelvin” (InK 1)
Full text linkWe report a summary of the technical achievements of the European Metrology Research Programme
Project (EMRP) ‘‘Implementing the new Kelvin” (InK 1). In short these are:
The first determination of definitive thermodynamic temperatures for the point of inflection of the
high temperature fixed points of Re-C, Pt-C and Co-C as well as a new evaluation of the Cu freezing
point.
The first trial of the new dissemination mechanisms for thermodynamic temperature at high temperatures,
as described in the mise en pratique for the definition of the kelvin (MeP-K).
A new ultra-low uncertainty thermodynamic evaluation of T T90 from about 30 K to 303 K, with particular
emphasis on temperatures around the water triple point (273.16 K).
The first re-evaluation of T T2000 from 0.02 K to about 1 K with an uncertainty of <1%.
Taken together these results represent a significant advance in primary thermometry. We also give a
brief introduction to the successor project (InK 2) and discuss the impact of this work on the kelvin redefinition
and next version of the MeP-K (i.e. the MeP-K-19
Pro-Pro: progress and problems of the experiment for the acoustic determination of the Boltzmann constant at INRIM
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