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.