Modulated temperature power compensation

Androsch, R., Moon, I., Kreitmeier, S., and Wunderlich, B. (2000). Determination of heat capacity with a sawtooth-t rpe, power compensated temperature-modulated DSC. Thermochimica acta. 357-358,267-278. 

There are three different types of DSC instruments power-compensated DSC, heat-flux DSC, and modulated DSC, Each produces a plot o power or heat flow versus temperature, called a thernuf ram. ... 

Androsch R, Moon I, Kreitmeier K, Wunderlich B (2000) Determination of Heat Capacity with a Sawtooth-type, Power-compensated Temperature-modulated DSC. Thermochim Acta 357/358 267-278. 

DTA as well as power compensation DSC instruments, and is called temperature modulated DSC, or TMDSC. The following trade marks are used by different TA instrument manufacturers for their temperature modulated differential scanning calorimeters Modulated DSC (MDSC ) of TA Instruments Inc., Oscillating DSC (ODSC ) of Seiko Instruments Inc., Alternating DSC (ADSC ) of Mettler-Toledo Inc. and Dynamic DSC (DDSC ) of Perkin-Elmer Corp. 

An extensive analysis of the sawtooth modulation brought a number of interesting results. Mathematically, it could be shown that if there were no temperature gradients within the sample and if all other lags and gradients could be assessed with the Fourier heat-flow equation, Eq. (11) does allow the calculation of the precise heat capacities [33]. Temperature gradients are, however, almost impossible to avoid. Especially in the power-compensated calorimeter, the temperature sensor is much closer to the heater than the sample and cannot avoid gradients. The empirical solution to this problem was to modify Eq. (11) as follows [34] ... 

An electrical resistance heater with more turns at the tube ends (to compensate for heat losses) surrounds each tube. There is a vertical laminar flow hood over the loading area to minimize particle contamination of the wafers being loaded. As we can see, there are temperature controls for the furnace tubes, and a power module to provide the electrical power. When operated as a LPCVD system, a unit including both the gas flow and vacuum systems is positioned on the right side. Such a unit is shown in Figure 8. Here we can see the vacuum pumps on the left, and the mass flow controllers on the right. The vacuum pump oil recirculation systems are shown in the slide out drawers. As can be seen in Figure 9, this system, as well as most current similar systems, operate under computer control. 

The reactor power regulation system is implemented as a software module within the Supervision and Control system. This system, when active, is responsible of regulating reactor power to its setpoint, compensating reactivity changes (temperature effects. Xenon, sample insertion, fuel bumup, etc.) and to perform power changes to new levels upon modification of the power setpoint... 

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