Experimental Checklist for the WizardExperimental Checklist for the Wizard
This page offers additional comments on proper experimental setup.
The DSC is operated with one or two purge gas flows depending on which cooling accessory is being used. The main purge gas which interacts with the sample is adjusted to 50 mL/minute. Gases such as nitrogen, air, oxygen or helium are typically used for this purge.
The Q Series™ DSC cells generally require a cooling accessory to be connected regardless of the type of experiment being run. The Quench Cool Accessory for the FACS is the only exception. It is removed before initiating heating ramp experiments.
The DSC operates in conjunction with one of the cooling accessories:
Finned Air Cooling System (FACS) is usable from ambient to 725°C
Refrigerated Cooling System (RCS) is usable from -90 to 550°C
Quench Cooler is usable from -180 to 550°C
NOTE: Only inert gases such as nitrogen can be used above 600°C. In addition there are multiple types of DSC pans available. Aluminum pans should not be used above 600°C.
Samples in DSC are placed in pans before introduction into the cell, so that as the samples melt or decompose, the cell is not contaminated. Since these pans are part of the heat flow path between the sample and the sensor, it is important that the pans are made of a thermally conductive material (e.g., metal) and that the contact at the "pan to sensor" and "pan to sample" interfaces is as uniform and low in resistance as possible. In the latter case (pan to sample), this means that the sample should contact the pan uniformly across the whole surface of the bottom of the pan.
For liquids or powders, this requirement presents little issue other than using enough sample to evenly cover the bottom of the pan.
For solids, however, proper sample form may be a larger issue. Nevertheless, the sample should be prepared so that a piece of appropriate weight with at least one flat side can be put into the pan with the flat side down.
Crimping the lid onto the pan often further improves the sample pan interface in these situations by pressing the sample against the bottom of the pan. Most samples can be run in non-hermetic pans either uncovered, or crimped with an aligned or inverted cover. Atmospheric interaction is optimized using an open (uncovered) pan. Crimped pans improve the thermal contact between the sample, pan and DSC cell disk, reduce thermal gradients in the sample, minimize spillage, and enable retention of the sample for further study. The crimped aluminum pans are most widely used. (NOTE: Make sure that you do not deform the bottom of the pan when you crimp the lid on the pan.) However, there are applications where the other non-hermetic pans are used.
After you have completed the steps needed in the wizard, you can:
Press the START RUN button to begin this run immediately.
or
Select Finish to close the wizard, storing the information you have entered. You may start this experiment later by selecting Control/Start, pressing the START on the tool bar, instrument keypad, or touch screen.