+/- 30 mu K temperature controller from 25 to 103 degrees C: Study and analysis

Unni, Madhvan PK and Gunasekaran, MK and Kumar, A (2003) +/- 30 mu K temperature controller from 25 to 103 degrees C: Study and analysis. In: Review of Scientific Instruments, 74 (1). pp. 231-243.

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Abstract

A simple two-stage metal thermostat, having a wide tolerance, has been built for performing light scattering studies in multicomponent liquid systems. It gives a temperature stability of ±30–45 µK for 1(1/2) h and ±60–90 µK for 7–14 h over a broad range of 25–103 °C. A detailed profile of thermal gradients within the sample recess is provided. The parameter\Delta$ T_{eff}$ [i.e., the difference between the maximum (minimum if \Delta $T_{eff}$ has a negative value) temperature within the sample recess and the temperature just outside the sample recess] seems to be more relevant than\Delta T (i.e., the temperature difference between the inner and the outer stages) in understanding the behavior of our thermostat. The thermal gradients can be tuned by varying \Delta$ T_{eff}$ (or by varying \Delta T). The least values of horizontal and vertical thermal gradients, i.e., 250 and 100 K/mm, respectively, are observed for\Delta $T_{eff}$ = 4.46 mK. The transient response of the controller is almost invariant for \Delta$ T_{eff}$>0, but it shows a dramatic decrease of almost 50% when \Delta$ T_{eff}$<0. On the whole, the limit\Delta$ T_{eff}$ --> 0, provides the best operating condition from all standpoints. A simple and effective compensation scheme to null the effect of extraneous parameters is employed. The importance of the stability of the bridge excitation source in improving the long-term stability of the controller is established.

Item Type:	Journal Article
Publication:	Review of Scientific Instruments
Publisher:	American Institute of Physics
Additional Information:	Copyright of this article belongs to American Institute Physics
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	01 Dec 2008 07:00
Last Modified:	19 Sep 2010 04:52
URI:	http://eprints.iisc.ac.in/id/eprint/16515

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