Specific heat of helium confined to micron-scale geometries near the lambda point

Most experiments to date on the effects of confinement on helium hal e been restricted to the submicron regime. However, using very high-resolution th ermometry techniques, it has become possible to explore the region extendin g up to about 100 mu m. This development dramatically increases the range o ver which length scaling can be tested and eases the problem of uncontrolle d surface effects. At the upper end of this length scale, experiments in sp ace are needed to reduce the transition broadening due to hydrostatic compr ession. We present the most recent results from a measurement of the specif ic heat of helium confined to 57 mu m thick planes and compare them with th eoretical predictions. We also describe some recent results obtained with h elium confined to cylindrical channels with diameters of 0.96 and 8 mu m (C ) 2000 Elsevier Science B.V. All rights reserved.