Two new deadweight force standard machines with capacities of 5 kN and 100 kN have been installed at IPQ. This paper describes the results of an intercomparison between the force standard machines of the National Metrology Institutes of Portugal (IPQ) and Germany (PTB). For the intercomparison, PTB used a set of force transfer standards which covered the whole force range from 50 N to 100 kN. The measurements were performed following the procedure used by PTB in intercomparison measurements. The influence of temperature differences in the various measurements was reduced by taking the temperature dependence of the force transducer sensitivity into account. This way of proceeding, considerable improved the results of the intercomparison and allowed relative deviations to be achieved which are smaller than the relative measurement uncertainty of the force standard machines.

A sensing element of column type was devised as a multi-component force/moment sensor by attaching strain gages. The ratio of length over diameter (L/D) for the sensing element was designed analytically and verified by finite element analysis. The fabricated sensor was evlauated by using a deadweight force/moment calibration machine within Korea Research Institute of Standards and Science (KRISS). The interference errors between force and moment components were minimized by addition and subtraction processes of signals obtained from strain gages. Finally the calibration showed that the interference error of F_x component was less than 7.3 % FS, and in case of other components, 5.0 % FS.

This paper describes the behaviour of deadweight force standard machines of 100 kN and 1 MN at the Physikalisch-Technische Bundesanstalt(PTB). A build-up system was used to measure the dynamic behaviour of the deadweight force standard machines. The oscillating signals from the force-transducers in a build-up system are much larger than those from a single force-transducer. This is because the force-transducers in a build-up system are located several tens of millimeters from the centre of the force-standard machine. Hence, small movements of the deadweight result in changes in the reaction forces of the build-up system, which are amplified by the lever mechanism. The frequency and the trajectory of the pendulum’s movements are investigated. The trajectories of the pendulum’s movements are estimated by using force signals from the build-up system. In addition to that, the major and minor radii, direction of the elliptic motion and the rotational direction as functions of time are estimated to interpret the pendulum’s movements more meaningfully. The two machines show somewhat different dynamic behaviour.

The IMGC-CNR recently acquired two new dead-weight Primary Force Standards, of 30 kN and 1 MN capacity, in addition to those already existing at the IMGC to meet the increasing demand from several industrial sectors in Italy for research and calibration work concerning force sensors and load cells to be used for weighing.
In the present paper the IMGC Primary Force Standards are shortly described and the increase of the dissemination of the Force Unit in Italy, on the basis of the number of the accreditation and certificates issued, is given. The main results of the metrological evaluation and long term stability of the calibration lever machines of one laboratory of the Italian Calibration Service are discussed.

We propose a simple scheme to characterize attosecond extreme ultraviolet (XUV) pulses. A broadband ultraviolet (UV) ~ vacuum ultraviolet (VUV) pump pulse creates a coherent super position of atomic bound states, from which photoionization takes place by the time-delayed attosecond XUV probe pulse. Information on the spectral phase of the XUV pulse can be extracted from the phase offset of the interference beating in the photoelectron spectra using a standard SPIDER (spectral phase interferometry for direct electric-field reconstruction) algorithm. We further discuss the influence of the chirp and polychromaticity of the pump pulse, and show that they do not spoil the reconstruction process. Since our scheme is applicable for various simple atoms such as H, He, and Cs, etc., and capable of characterizing attosecond XUV pulses with a pulse duration of a few hundred attoseconds or even less, it can be an alternative technique to characterize attosecond XUV pulses. Specific numerical examples are presented for the H atom utilizing the 2p and 3p states.