Calibration to obtain the cell resistance and capacitance values involves two experiments. The first is based on heating an empty cell over the same temperature range that will be used in subsequent sample experiments. The first calibration experiment is referred to as the Baseline Run.
Follow the instructions on the calibration window using the information below as a guideline:
Conduct Experiment: This option allows you to determine whether you want to create a new Baseline Run experiment or use a previously stored Baseline Run file. If you check this box, you must complete the other entry fields on this window, including enter a data filename where the Baseline Run information will be stored. (This is the default selection.) If you do not check "Conduct Experiment," you must complete the "Enter existing Tzero Baseline data file" field at the bottom of the window by selecting the filename of your previously stored Baseline Run. Then press Next to proceed to the sapphire run experiment.
Calibration Range: Select the desired option from the drop-down menu. "Heat only calibration" is used when you are interested measuring transitions or heat capacity while heating the sample. The "Heat and Cool calibration" is used when you are interested in both heating and cooling data when measuring transitions or heat capacity (this option takes longer to calibrate). The resulting heat or cool plots are displayed separately.
Lower Temperature & Upper Temperature: Calibration must be performed using the same atmosphere and cooling accessory that will be used in subsequent experiments. Obviously, the lower and upper temperatures chosen for calibration must be within the operating range of the cooling accessory selected. In addition, the temperature range for calibration should be at least as broad as the range that will be used in subsequent experiments on your samples. Typical temperature ranges are: -180 to 400 °C for the LNCS, -40 to 400°C for the RCS40, -90 to 400°C for the RCS90, and 50 to 400 °C for the FACS. See also: Introducing the DSC Cooling Accessories. NOTE: The quench cooler cannot be used for Tzero calibration and experimentation.
Ramp Rate: Calibration can be performed for heating only or for heating and cooling. The minimum ramp rate is 10°C/min in order to obtain reliable values for sensor thermal capacitance and resistance. Lower ramp rates provide weaker signals and less accuracy. For heat-only calibration, a ramp rate of 20°C/min is recommended. For heat and cool calibration, a rate of 10°C/min may be more practical since it may not be possible to maintain a higher cooling rate down to the lowest temperature of interest. Obviously, the type of cooling accessory determines the maximum cooling rate and minimum temperature for calibration.
Data Filename: This field is active when "Conduct Experiment" is selected. Enter the filename and the location desired to store the Baseline Run information. NOTE: When using a 21 CFR 11-licensed system, the Data Filename feature is not available. In its place is SUID# and Project Name. The SUID# is automatically generated by the database and cannot be altered. Select the desired Project from the drop-down list.
Purge Gas & Flow Rate: Calibration should be performed using the same purge gas and flow rate as that which will be used in subsequent experiments on your materials. Select the gas from the drop-down menu provided. (The DSC allows you to plumb in two different purge gases. Those are set up outside of this wizard through the Instrument Preferences. Purge gas selections available are air, nitrogen, oxygen, helium, argon, and "outside." "Outside" gas is used for all other non-standard gases that you might want to use. The selection in this calibration wizard is between our previously selected Gas 1 and Gas 2.) The range of acceptable flow rates is 0 to 150mL/min. 50 mL/min is recommended for most DSC experiments.
Post Test: Use this button to access the Post-Test condition parameters that allow you to specify the temperature window once the experiment is complete.
Once all of the experimental parameters are entered, press Next
to start the baseline experiment. For information on the next step, performing
a sapphire run, click here more.
For information on the Experiment
in Progress window or on results of the calibration experiment
click here DSC
Calibration Wizard Experiment.