Position-Sensitive Transition-Edge Sensors (PoSTs)


A Position-Sensitive Transition-Edge Sensor (PoST) is a novel microcalorimeter we are developing for large format imaging spectrometers. The idea is very simple: several absorbers are strung together thermally with a thermal conductance Ga between each. TES thermometers are placed at either end of the absorber chain and connected to a cold bath at temperature Tb through a thermal conductance G. When a photon hits the PoST, heat flows to either end and is readout by the TESs. The position of the photon is inferred from difference in pulse heights between the two TESs. The energy of the X-ray is determined from the sum of the two pulses. A PoST with 10 absorbers and two TESs would provide 5 times more pixels than a single-pixel TES.