A method and apparatus for rapid temperature changes of thin samples is
disclosed. The apparatus comprises of a thin-film resistive element
embedded in a membrane, a narrow gap between the membrane and a heat
sink, and a control circuit. The resistive element acts both as a heater
and as a temperature sensor to reduce time constant of the control
circuit. The gap between the membrane and the heat sink is filled with
gas (e.g., N.sub.2 or He) acting as cooling medium with low thermal
inertia. The temperature controller has a microsecond time constant,
which allows adjusting rapidly the power applied to the membrane,
depending on heat released/absorbed by a sample during an isotherm or
during a given rate of temperature changes. The membrane has low thermal
inertia and, coupled with high-speed temperature controller, allows
controlled cooling and heating rates up to 100 000 K s.sup.-1 and higher.
The method can be a core of any setup where controlled fast
temperature-time profile of thin or small sample is desirable. The
proposed control circuit can be readily applied to the variety of the
existing setups with resistive heater.