Sample mounting
Page 5 of 7
Pocket with clamps
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One or two samples of irregular shape, with low conductivity or with other properties preventing them from mounting like crystals or silicon wafers can be mounted to the "metallic pocket", usually spot-welded from Ta wires and sheets. A specially designed broad pocket permits to insert two samples at the same time. In the example you can see a silicon wafer in the single pocket and a silicon wafer plus a hat-shaped crystal in the double pocket. |
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The sample is simply clamped by the pre-stressed sheet so thermal contact with pocket is not always excellent and uniform. It can also cause difference between thermocouple reading and the real temperature of the sample surface. The error can be up to 100 K/°C. Maximum annealing temperature is about 700 °C/1000 K and the maximum annealing current is 20 A. The sample is theoretically at half of the annealing voltage so it is difficult to acquire spectra during annealing. |
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Assembly:
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For the correct thermocouple pin contact the pins must stick out 3.8-4 mm below the baseplate bottom surface. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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For the correct connection the annealing contacts must be 3.6-3.8 mm above the baseplate top surface. This distance (if 3.5 mm or lower) can be increased by placing tiny spacers made of properly thick wire below the bottom ceramic spacers (3a) or swapping the thin ceramic spacers (3a) with the thicker ones (3b). Check in the areas labelled by green circles that the pocket (8.1 or 8.2) is not touching directly the annealing contacts (7ab). In such case the annealing current would not flow through the annealing wires but directly through the pocket which would make the annealing inefficient and high temperatures could not be reached. |
Last Updated on Thursday, 09 March 2023 10:32