Soft Report - Dipartimento di Fisica - Sapienza

Spectroscopy Laboratory - UdR PerugiaCryostatLASERTandem Fabry-Perot interferometer Theexciting source is a Coherent-Innova 300 modelargon ion laser operating with a typical power of300-500 mW on a single mode of the λ 0=514.5 nmline. The light scattered by the sample is analyzedby means of a Sandercock-type (3+3)-pass tandemFabry-Perot interferometer, which supplies the bestcombination of high resolution and goodthroughput, whit a finesse of about 100 and acontrast >10 10 . By varying the mirror spacing(d=0.05mm, 20mm), it is possible to collect spectracovering the 0.1-300 GHz frequency range selectingdifferent polarization geometries. The frequencyresolution of this apparatus is about 100 MHz, andthe maximum exchanged wave-vector achievable isabout 0.04 nm -1 .Control anddata aquisitionDielectric spectroscopy setup Dielectric spectrometer based on aNovocontrol Alpha S setup operating in the frequency rangebetween 0.01 and 107Hz and on HP8720C and HP8753A networkanalysers in the range 107–2·1010Hz.Photon Correlation Setup. The light source is a diode pumpedsingle mode (the λ 0=532 nm) solid state laser (Coherent)operating with a typical power of 400 mW. The setup is usuallyused in 90° scattering geometry and the light scattered by thesample, after polarization, is collected by a photomutiplier tubeand analysed by a Brookhaven BI-9000 AT correlator, a digitalsignal processor which can be used with low, mid and high speedselections of the channels (max number channels:466), withdifferent sampling time ranges, allowing to make measurementsfrom 25 ns to 1310 s. For measurements as a function of theangle, the apparatus with sample holder can be also equippedwith a 200mm turntable mounted on a circular base, withmanual or motor driven selection of angles 0.01° steps.Dielectric Spectroscopy Laboratory - UdR PisaHigh-Pressure apparatus for electric measurements. In the centralpart of the picture we can see the Berillium-Copper pressure room in whichthe sample can be inserted. Specially designed feed-throughs (top of thecell) connect the sample with the High Resolution Dielectric Analyzer fromNovocontrol, which is used for electric measurements. A thermostaticjacket is wrapped around the pressure room, enabling the control oftemperature by means of a circulators from Huber (Unistat 380w).Pressure variations, produced by a manual pump, are transmitted to thesample through a fluid. The apparatus can be used for electricmeasurements of liquid and solid samples in the frequency range 10 -5 -10 7Hz, over the temperature interval from 353 K to 193 K, and in the pressureinterval from 0.1 MPa to 700 MPa. The resolution of the electricmeasurements expressed in terms of loss factor tanδ is better than 10 -3 inthe whole frequency range (UdR Pisa)21SOFT Scientific Report 2004-06