Abstract: A broadband photon detector capable of detecting a steady state flux of incident radiation operates using a superconducting material is biased at the temperature where the material changes from a superconducting to a non-superconducting state. Photons which strike said material cause a temperature rise and a measurable increase in resistivity of the material that continues until the radiation ceases. The superconducting material for detecting the incident radiation is formed as a strip on microspheres that act as a substrate to make as small a heat sink as possible.