High Count-Rate Studies of Small-Pitch Transition-Edge Sensor X-ray Microcalorimeters

We are developing kilo-pixel arrays of small-pitch transition-edge sensors for high spectral-resolving, high count-rate applications in astrophysics and solar physics measurements. We have fabricated and tested pixels that are \(65\,\upmu \)m in size on a silicon substrate with an X-ray flux of \({\sim }100\) counts per second (cps) per pixel. The X-ray pulses were recorded and analyzed in various ways to obtain high throughput with good energy resolution. We have demonstrated 2.3 eV FWHM resolution with 99.6 % throughput for a 6-keV X-ray flux of 100 cps.