The science and technology of microcalorimeter arrays

I will review the present status and future prospects for arrays of microcalorimeters used for high-resolution photon spectroscopy. The various applications impose different constraints on the array designs, but there are many common physics and engineering issues as well. I will present both the unique and the shared aspects of their design, fabrication, and operation. As we are well into the age of small microcalorimeter arrays, I will present the performance of a variety of functioning arrays. Arrays with more than 1000 pixels are under development; I will report on their progress and on the technical issues associated with arrays of this scale and larger.