Sample Cells Dielectric- Conductivity- Impedance
Transcription
Sample Cells Dielectric- Conductivity- Impedance
Sample Cells for • Dielectric- • Conductivity- and • Impedance Measurements on Materials • cells for measurements with ultimate accuracy • broad frequency range from DC to 2 GHz • wide temperature range from -200 °C to +500 °C • measures low loss materials with extremely high input impedance • modular system : all cells fit in one common cryostat Manufacturer: NOVOCONTROL GmbH Obererbacher Strasse 9 D-56414 Hundsangen Germany Phone: ++(0)6435 - 96230 Fax: ++(0)6435 - 962333 e-mail [email protected] WWW http://www.novocontrol.com isolation prevent evaporation of sample material out of the cell. The BDS 1309 is mounted in the same way as the standard sandwich capacitor between the electrodes of the BDS 1200 or BDS-S active sample cell. BDS 1200 Connection Head This is the standard sample cell for the low frequency range from DC to 3 MHz including a temperature sensor. BDS 1101 Sample Cell for High Conductive Materials The temperature range is from -200°C to 450 °C (optional 500°C). The sample cell can be operated with the NOVOCONTROL QUATRO or NOVOCOOL Cryosystems or the NOVOTHERM temperature control system. The sample material is prepared between two additional external electrodes as a sandwich capacitor. 6DPSOH0DWHULDO ([WHUQDO(OHFWURGHV to sample is done by rigid air insulated RF-lines. The temperature range and other features correspond to the BDS 1200 sample cell. BDS 1308 Sample Cell for Liquids with Low Viscosity For some low viscosity liquids with low partial pressure, sample material may evaporate out of the standard sandwich capacitor and the measurement accuracy may decrease. In order to prevent evaporation, the sample cell BDS 1309 can be used. 6LOLFD6SDFHUV R ound gold plated electrodes are available with 20/30/40 mm diameter. After the preparation, the sandwich capacitor is mounted between the electrodes of the BDS 1200 sample cell. BDC-S Active Sample Cell This is a special version of the BDS 1200 standard sample cell with optimised high frequency performance. It allows to perform dielectric, conductivity or impedance measurements from 10 µHz up to 10 MHz. In contrast to the BDS 1200 sample cell, the BDC-S active sample cell is not connected to the impedance analyzer by BNCcables, limiting the performance at high frequencies. Instead, an active impedance converter mounted on top of the sample cell is used and the connection In the open state, the cell closing plate and upper electrode are removed from the cell, and the sample material covers the the lower electrode. The electrode gap is adjusted by silica spacers. In the closed state, the upper electrode is pressed by the cell closing plate ans the spring to the spacers. Liquid sample material, which does not fit between the electrodes, can flow around the upper electrode. The two seal rings attached to the Teflon This is a special version of the BDS 1200 sample cell for conductive materials like metals or super conductors. The sample geometry should be a thin cylinder or wire. The measurement is done in the normal 4 wire arrangement. Two wires are used to insert the current into the sample. The other two wires are used to measure the voltage in the sample. This cell allows to measure impedance down to the µΩ range, but is not suited for dielectric samples. The temperature range and other features correspond to the BDS 1200 sample cell. Interdigit Comb Electrodes In this arrangement, the sample material (generally a liquid) covers the surface of a comb micro structure electrode. The interdigit electrodes may be used in combination with the BDS 1200 connection head for temperature dependent measurements or direct connected to the impedance converter. Compared to the BDS 1309 sample cell, the interdigit electrodes are less accurate but easier to handle. BDS 2200 Coaxial RF Sample Cell is for Dielectric, Conductivity and Impedance measurements from 1 MHz to 1.8 GHz. This cell can be connected to a RF impedance reflectometer (e. g. Hewlett Packard 4291 or 4191). The sample is prepared between two sandwich electrodes building a sample capacitor similar to the BDS 1200 sample cell. Sample capacitor electrodes are available from 3 .. 12 mm diameter. Electrode spacing may be selected between 10 µm and 5 mm. The sample capacitor terminates the coaxial measurement input of the analyzer. The reflection, depending on the sample impedance is measured. For temperature dependent measurements, the BDS 2201 RF extension line is recommended. This is a high temperature stable, low loss precision line with two APC-7 connectors. It is mounted between the impedance input of the reflectometer and the sam- ple cell for thermal isolation. This combination (sample cell and extension line ) can be operated in the temperature range from -200 °C to 450 °C. BDS 2300 RF Mounting Rack This is a complete high frequency extension for RF measurements and temperature control for the QUATRO Cryosystem. It contains a BDS 2200 coaxial sample cell, a BDS 2201 RF extension line and a mounting rack which connects the test station (impedance input) of the HP 4291 analyzer, the extension line, the sample cell and the QUATRO Cryosystem to a turn key system. The mounting rack allows to move the sample cell in and out of the cryostat by special mechanics. The HP 4291 analyzer, the Cryostat BDS 1100 and the QUATRO Cryosystem are not included in BDS 2300.