High-energy-resolution cryogenic microcalorimeters are a powerful new tool for x-ray microanalysis. 1 With demonstrated energy resolution ~20 times better than with conventional semiconductor EDS, microcalorimeters are useful in applications such as nanoscale particle analysis. Unfortunately, single x-ray microcalorimeters are limited by low count rate (~500 s -1 ) and small area (~ 0.16 mm 2 ). Both the count rate and the area can be improved by the implementation of arrays of microcalorimeters. In principle, this improvement in count rate and area comes without degraded energy resolution. The implementation of small microcalorimeter arrays will lead to improvements in the minimum detectable size of nanoscale particles and in the trace element concentration detection limit for a fixed analysis time. The development of kilopixel arrays capable of acquiring hundreds of thousands of counts per second, and with collecting areas of order 50 mm 2 , will make it possible to collect high-statistics spectra in small fractions of a second. This will make new applications possible, including real-time process-stream monitoring and the study of the evolution of film properties during deposition with x-ray fluorescence.Before fabricating an array, it is useful to demonstrate the operation of a single-pixel microcalorimeter system in different environments. We have now transferred a single-pixel microcalorimeter system from Boulder, Colorado to the Chemical Science and Technology Laboratory in Gaithersburg, Maryland. In the process of transferring the system, we discovered that our shadowmask-fabricated microcalorimeters based on aluminum-silver bilayers were not stable in the humid environment of Maryland. We now fabricate microcalorimeters photolithographically, using the immiscible molybdenum-copper material system, which we have found to be stable and robust. An example spectrum taken with the system in Gaithersburg, Maryland, is shown in Figure 1. The microcalorimeter is a 0.16 mm 2 molybdenum-copper bilayer with a 3-µm-thick bismuth absorber. The energy resolution with real-time analog signal processing is ~7 eV. This result compares well with the ~4 eV achieved with aluminum-silver bilayers, since the saturation energy of the new detectors is significantly higher. We will use molybdenum-copper bilayers in arrays.In order to fabricate large arrays, it is necessary to develop an array structure that thermally isolates the adjacent pixels, while still allowing the leads to be extracted from the array to instrument the microcalorimeters. We fabricate single pixels on a silicon-nitride-coated silicon wafer. To create the needed thermal isolation, we remove the silicon beneath the microcalorimeter using a wet KOH etch, leaving the microcalorimeter on a suspended silicon-nitride membrane. Unfortunately, fabricating large arrays with thermally isolated pixels using this approach is difficult. To make it possible to fabricate large arrays, we are developing surface micromachining techniques to make arrays of silicon nitride pl...

<p>Anodic aluminium oxide has been identified as a versatile porous template material having high pore density, (up to 1010 cm-2), controllable channel length and monodisperse pore diameter within the range 20-250 nm. A number of studies have demonstrated the concept of utilizing the porous structure for directing the growth of various nanostructures. An example of this is the growth of crystals of the aluminophosphate AlPO4-5 within the anodic nanochannels. The high aspect ratio of the template pores encourages growth of the crystals in the preferred c-axis orientation. We have produced membranes of this material and investigated the degree of crystal alignment using X-ray diffraction. The relative degree of preferred orientation is over 200 for a typical membrane. Field emission SEM micrographs clearly show the aligned crystals within the pores. The inclusion of luminescent guest molecules within the pores of the zeolite has also been achieved. This work describes the synthesis, characterization and potential application of these membranes.</p>