Quenching of the Deuteron in Flight

We investigate the Lorentz contraction of a deuteron in flight. Our starting point is the Blankenbecler-Sugar projection of the Bethe-Salpeter equation to a 3-dimensional quasi potential equation, wqhich we apply for the deuteron bound in an harmonic oscillator potential (for an analytical result) and by the Bonn NN potential for a more realistic estimate. We find substantial quenching with increasing external momenta and a significant modification of the high momentum spectrum of the deuteron.Comment: 11 pages, 4 figure

First Experience with the Transportable MPG-2 Absolute Gravimeter

We report on design details and first results obtained with the transportable absolute gravimeter MPG-2 (“Max-Planck-Gravimeter”). It is developed as an evolution of the stationary device MPG-1, completed in 2007. The MPG-2 is built on a common scheme where the position of a freely falling object is monitored. The setup consists of a ballistic block, an interferometer and the electronics. Free fall drops can be repeated every 10 s with the standard deviation close to 30 μgal. A one-day gravity observation gives a result with a standard deviation of the mean of less than 5 μgal. A prototype of the MPG-2 took part in the ECAG-2007. New measurements at the reference gravity station “Bad Homburg”, Germany confirmed the declared combined standard uncertainty of 50 μgal

Improvements of the MPG-2 transportable absolute ballistic gravimeter

The MPG-2 (Max-Planck-Gravimeter) is a transportable absolute gravimeter built on a classical free-fall scheme to measure the local gravity value. With significant improvements and further investigations in recent years, the standard deviation of the mean for a typical measurement over 12 h to 24 h is 1.0 µGal to 3.0 µGal (1 µGal = 10 −8  m s −2 ), and the combined standard uncertainty is estimated to be less than 10 µGal. The major improvements include the new interferometer design and alignment, longer drop length, reduced recoil effects and demagnetization of the falling body. The revised uncertainty budget and new measurement results of MPG-2 are reported. The results of observations at the reference gravity station Bad Homburg confirmed the revised uncertainty budget

Reply to the 'Comment on Comparison of three digital fringe signal processing methods in a ballistic free-fall absolute gravimeter'

This paper reports results of comparison of three digital fringe signal processing methods implemented in the same free-fall absolute gravimeter. A two-sample zero-crossing method, a windowed second-difference method and a method of non-linear least-squares adjustment on the undersampled fringe signal are compared in numerical simulations, hardware tests and actual measurements with the MPG-2 absolute gravimeter, developed at the Max Planck Institute for the Science of Light, Germany. The two-sample zero-crossing method realizes data location schemes that are both equally spaced in distance and equally spaced in time (EST) along the free-fall trajectory. The windowed second-difference method and the method of non-linear least-squares adjustment with complex heterodyne demodulation operate with the EST data. Results of the comparison verify an agreement of the three methods within one part in 10 9 of the measured gravity value, provided a common data location scheme is considered

Improvements of the MPG-2 transportable absolute ballistic gravimeter

The MPG-2 (Max-Planck-Gravimeter) is a transportable absolute gravimeter built on a classical free-fall scheme to measure the local gravity value. With significant improvements and further investigations in recent years, the standard deviation of the mean for a typical measurement over 12 h to 24 h is 1.0 mu Gal to 3.0 mu Gal (1 mu Gal = 10(-8) ms(-2)), and the combined standard uncertainty is estimated to be less than 10 mu Gal. The major improvements include the new interferometer design and alignment, longer drop length, reduced recoil effects and demagnetization of the falling body. The revised uncertainty budget and new measurement results of MPG-2 are reported. The results of observations at the reference gravity station Bad Homburg confirmed the revised uncertainty budget

Development of new free-fall absolute gravimeters

The design and first results of two free-fall absolute gravimeters are reported: a stationary gravimeter is designed and can be used as a reference system and a portable gravimeter is aimed at field measurements. The determination of the acceleration due to gravity is done interferometrically in both instruments. The whole fringe signal is digitized by a high-speed analogue-to-digital converter, which is locked to a rubidium frequency standard. This fringe recording and processing is novel as compared with commercial free-fall gravimeters, which use an electronic zero-crossing discrimination. Advantages such as the application of a zero-phase-shifting digital filter to the digitized data are depicted. The portable gravimeter's mechanics deviate from the conventional type. Springs are used to accelerate and decelerate the carriage supporting the falling object. A detailed uncertainty budget is given for both gravimeters. The combined standard uncertainty for the portable and for the stationary gravimeter is estimated at 38.8 µGal and 16.6 µGal, respectively. The corresponding statistical uncertainties are 1.6 µGal (over one day of measurement) and 0.6 µGal (over one month of measurement). The different designs and dimensions of the new free-fall gravimeters can help to reveal unknown or so far underestimated systematic effects. The assessments of the uncertainties due to seismic noise and shock vibrations, and electronic phase shifts give validity to this assumption