A variable temperature dewar has been designed and built at the solid state laboratory of the University of British Columbia for infra-red absorption experiments at low temperatures. The dewar features a rotatable sample holder which brings any one of three samples into the light beam for comparison measurements. A removable tail section permits easy access to the samples.
The dewar has been successfully operated over the 4°K to 50°K range. It can maintain sample temperatures to within 1°K for periods up to two hours. Approximately ten minutes is required to achieve any desired temperature in the operating range.
The construction and calibration of a copper vs. constantan thermocouple is described. The thermocouple was used to measure the sample temperatures to an accuracy of about 1°K. Temperature variations of a few tenths of a degree could be detected.
As a demonstration of the dewar's capabilities, an experiment was performed to measure the line width dependence of hole transitions from the ground state of the P3/2 band to the first excited state in the P1/2 band in boron doped silicon. The experiment showed that the line broadening starts at about 20°K and increases at higher temperatures.
Several methods of improving the performance of the dewar are suggested. / Science, Faculty of / Physics and Astronomy, Department of / Graduate
| Identifer | oai:union.ndltd.org:UBC/oai:circle.library.ubc.ca:2429/37083 |
| Date | January 1965 |
| Creators | MacPherson, Ronald William |
| Publisher | University of British Columbia |
| Source Sets | University of British Columbia |
| Language | English |
| Detected Language | English |
| Type | Text, Thesis/Dissertation |
| Rights | For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use. |
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