No abstract

No abstract

No abstract

Usually, the temperature in boreholes is determined using a standard temperature probe. The logging technique is either “stop and go”, or the probe is lowered as a moving probe into the borehole using a controlled speed. Distributed temperature probe arrays installed permanently in a borehole are an alternative to moving probes and can be applied especially for temperature monitoring even under conditions where moving probes cannot be used. The distributed optical fiber sensing technique represents a new approach for temperature measurements. The basis for this method is given in Boiarski (1993), Dakin et al. (1985), Farries and Rogers (1984), Hartog and Gamble (1991), Rogers (1988), Rogers (1993). First results using fiber optic temperature sensing in boreholes and temperature monitoring for studying geotechnical and environmental problems (e.g., waste deposits) are published in Hurtig et al. (1993; 1994; 1995) and Hurtig and Schrötter (1993).

The lattice parameter of a highly perfect monocrystalline silicon sample is measured in six laboratories using three different diffraction methods. The quality of the measurements and of the applied corrections is already sufficiently high to compare lattice parameters measured by means of the used methods and CuKα radiation on an absolute scale with an accuracy of about Δa/a = 3 × 10−6.