Development of a Pico-joule Calorimeter Instrument

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9803019AllenAdvances in techniques of micro-machining small microheater elements and the availability of high precision electronics have generated a new class of heat sensing instruments. These advances will have major impact in developing a new ultra-sensitive calorimetry instrument for measuring energy beyond nanojoule to picojoule sensitivities. This award provides support to develop a calorimeter which will have picojoule sensitivity by using novel micro-machining techniques. This instrument will be used for fundamental energy measurements in material systems ranging from interactions between clusters containing only a hundred atoms to the real time measurement of nanoliter biological samples.Calorimetry is the ideal tool for studying the fundamental properties of material, e.g. the melting point, heat of fusion, and the heat capacity. However, until recently calorimetry was limited to studies of bulk material. Now, new advances have provided us with the first opportunity to apply this powerful technique on the nanometer scale of material, at dimensions where material properties deviate tremendously from their bulk values. A recent article in SCIENCE by Bertsch [1] entitled " Enhanced Melting in Clusters," highlights the new breakthrough techniques in calorimetry. He discusses the size-dependent phenomenon of reduced melting temperature of free clusters in a beam [2] and on a surface [3].Using the new technology, the proposed instrument will generate a quantum leap in sensitivity of factor of 10,000 over any current conventional systems. This increased sensitivity will allow exploration of material characterization at a new level of thermodynamic measurement.The picocalorimeter will be applied to a broad range of collaborative materials studies including (i) enhanced melting point studies, (ii) direct thermodynamic studies of nucleation, coalescence and growth of surface clusters during film growth, (iii) defect recovery of ion-implant damage during thermal annealing, (iv) surface reconstruction of Liquid Crystal (LC) fluorinated block polymers, and (v) studies of cell division in a single-cell embryo.Faculty and students from the University of Illinois, University of Chicago, and Cornell University will be involved with the development of this new instrument.%%%***