[en] The production of Charm at LEP-energy is mainly due to the following sources: direct decay of Z⁰ bosons into cc pairs Z⁰→cc with consecutive hadronisation of the c-quark, or B-meson production via the process Z⁰→bb with subsequent decay of the b- to a c-quark. Charm production can be observed most easily via tagging of D^*±(2010)-mesons. Due to the small difference between D^*± and D⁰ (ΔM = 145 MeV) the Q-value of the reaction D^*± → D⁰π_s^± is about 6 MeV/c² only and therefore sets an upper limit for the momentum of the soft pion transvers to the D^*±-line of flight. This can be seen as an enhancement in the low region above the p²_T-background spectrum. Applying this Low-p_T-method the ratio of Z⁰-partial decay widths into charm quarks and hadrons of Γ_Z⁰→cc/Γ_had = 0.168±0.010(stat.)±0.072(syst.) has been found with the L3-detector which is in very good agreement with the Standard Model prediction of Γ_Z⁰→cc/Γ_had = 0.171. Using Γ_had = 1747 MeV from a previous L3-measurement the Z⁰ decay width into Charm quarks was determined to be Γ_Z⁰→cc 293±18(stat.)±128(syst.)MeV. About 390000 hadronic Z⁰-decays of the year 1992 have been used for the analysis. (author) figs., tabs., 43 refs

[en] The tritium disposal plant consists of overground and underground areas. The construction and operation of the plant in the above ground area is examined for stationary and mobile design (in containers). The underground area of the hole and the gatekeeper's building are stationary. Release possibilities in correct operation and for incidents and accidents and their radiological effects for the operating staff and the environment were examined for the planned plant (stationary and mobile). It was found that the limits given by StrlSchV can be compiled with, even using conservative boundary conditions. The final store for waste water containing tritium will be shut down after the operating phase. The hole must be tightly sealed. A permanent closing off of the injection horizon from the biosphere is proposed. The study contains an outline program and a cost estimate. From the present point of view, operation of the plant for disposing of waste water containing tritium can be started in 1996 at the earliest. (orig./PW)

[en] Within the framework of the project, a combined EMR and temperature borehole probing equipment has been developed for applications in explosible areas of zone 1, according to explosibility groups IIA and temperature category T3. The probe has been tested and was found to be suitable for vertical, slant, and horizontal drilling work up to a depth of 1000 m, in unworked salt rock at the Gorleben site. Furthermore, a mobile, battery-powered EMR measuring unit with digital recording systems has been developed for underground exploration starting from mine roads and worked spaces. (orig./HP)

[en] The use of cepstral gating to estimate the reflector series directly has led sometimes of erroneous results, especially in the fine structure investigations. In addition, it should be noted that the estimated sequences are in general uniformly time-delayed. It is mainly due to cepstral disturbances caused by mixed-delay reflector series, time-varying character of source signal and additive noise. This paper is directed toward recovering the reflector series by determining the beginning position of the estimated wavelets. It is based on the short-time homomorphic analysis comprizing a number of windows. Considering the fact that the low-time values of the segment's complex cepstrum are determined only by one of the several wavelet arrivals and after research we have estimated in each short-time segment only one reflector impulse which can be in the first approximation well matched to the recovered wavelet. This technique is illustrated by means of both synthetic- and real data

[en] The emission of greenhouse gases and the resulting global warming is one of the most important and challenging issues of the 21st century. Carbon dioxide is one of the major contributors to the greenhouse effect and its atmospheric abundance has growing constantly since the beginning of the industrialization. The isotope ratios n(13C)/n(12C) and n(18O)/n(16O) are important tools for studying the impact of anthropogenic CO2. Usually, isotopic compositions of CO2 are reported as δ-values, that express isotope ratios relative to an artifact based on a fossil calcite called VPDB. This relative VPDB scale was necessary, since absolute and SI-traceable isotope ratios of CO2 are currently not available, neither by isotope ratio mass spectrometry (IRMS) nor by optical isotope ratio spectroscopy (OIRS). In this study we present a potential way of deriving absolute carbon and oxygen isotope ratios of carbon dioxide via IRMS based on the gravimetric mixture approach. Besides practical improvements like an air buoyancy correction scheme for masses of gases, we show first results applying our method which demonstrate its feasibility, limitations, and achievable uncertainties. Also, we show the mathematics behind our approach and discuss further improvements and applications. Furthermore, we show how these absolute ratios can be used in field applications by OIRS methods including a new approach on OIRS uncertainty assessments according to the GUM. For this contribution we report on our recent results within in the European metrology research projects SIRS (16ENV06). and STELLAR (19ENV05).

[en] The Karlsruhe Tritium Neutrino (KATRIN) experiment is a large-scale effort to probe the absolute neutrino mass scale with a sensitivity of 0.2 eV (90% confidence level), via a precise measurement of the endpoint spectrum of tritium β-decay. This work documents several KATRIN commissioning milestones: the complete assembly of the experimental beamline, the successful transmission of electrons from three sources through the beamline to the primary detector, and tests of ion transport and retention. In the First Light commissioning campaign of autumn 2016, photoelectrons were generated at the rear wall and ions were created by a dedicated ion source attached to the rear section; in July 2017, gaseous ^83mKr was injected into the KATRIN source section, and a condensed ^83mKr source was deployed in the transport section. In this paper we describe the technical details of the apparatus and the configuration for each measurement, and give first results on source and system performance. In conclusion, we have successfully achieved transmission from all four sources, established system stability, and characterized many aspects of the apparatus.

[en] In this paper European space weather activities are sketched and the contribution of cosmic ray research and technology to the European space situational awareness programme is described. Especially the cosmic ray muon detection technique is studied - on ground and in future space based -, because it is considered to be very useful for coronal mass ejection forecast in the next solar maximum between 2011 and 2012. (authors)

[en] A horizontal drilling program of about 7000 m was performed in a potash mine in northern Germany. The program objective was to keep the course of the borehole within a tolerance cylinder 5 m in diameter. Oriented cores not less than 40 mm in diameter, a core recovery of 95% per core run, and an increasing efficiency of the wire-line drilling method should be achieved by extending the usable length of the inner core barrel. The R and D project yielded the following results: Control of the vertical borehole course was generally possible with a precision of +-2.50 m deviation from the ideal position by means of appropriate stabilizer placement near the bit. Steering of the horizontal borehole course was managed applying a clockwise or anticlockwise rotating drill string. Thus, systematic effects caused by the vertical control mechanism were used for correcting the horizontal course of the borehole. A precision of +-2.50 m deviation from the ideal horizontal position was not always attained, but at least the final horizontal deviations could be limited to 1 to 2% of the final length of the borehole. An essential help for the vertical and horizontal navigation of the borehole course was the consistent application of the data unit for recording drilling parameters. It was therefore possible to analyze the influence of weight on bit and rotational speed on the course of the borehole with respect to stabilizer placements and geology. The maximal length of a borehole was 1522 m. An efficient drilling method that allows successful steering of the borehole course in horizontal and vertical direction under operational conditions has been developed

No abstract available

[en] The results are reported of a case study of two Pi 2 pulsations observed near the eastward electrojet by the Scandinavian Magnetometer Array. The power of the two Pi 2 pulsations, calculated using a standard Fast Fourier Transform method, peaks near the centre of the eastward electrojet. For both events there is a strong latitudinal gradient in the power poleward of the equatorward border of the electrojet. The sense of polarisation is predominantly clockwise at the northern stations and anticlockwise at the southern stations although the reversal from clockwise to anticlockwise does not occur at a constant latitude. For the first event the polarisation reversal occurs at higher latitudes in the western half of the array; for the second the polarisation reversal occurs at higher latitudes at the edges of the array. The polarisation reversal does not appear to be related to the location of the eastward electrojet. Equivalent current vectors of the Pi 2 pulsations, obtained by rotating the band pass filtered data through 90⁰, exhibit clear vortex structures in both events. The vortices change sense of direction at half the period of the Pi 2 pulsation. A simple model for the ionospheric electric field in accord with the field line resonance theory reconstructs the basic features of the observed Pi 2 equivalent current system. It is thus concluded that Pi 2 signatures in the region of the eastward electrojet and far away from the auroral break-up region are governed by the field line resonance mechanism. (author)