Noise and signal analysis of Ir/Au TES with asymmetrical slits parallel to the electric current
ABSTRACT A multi-pixel TES array is one of the attractive methods to read-out the incident x-ray position, which simplifies a read-out circuit for imaging applications. We fabricated a ten-pixel Ir/Au TES microcalorimeter with asymmetrical slits parallel to the electric current, and analyzed its noise and signal characteristics. The device was successfully operated in a strong electro-thermal feedback (ETF) mode. However, very large excess noise is observed, which cannot be explained by the noise theory for a single pixel TES. We have modeled the multi-pixel TES array as separated thermal group components, and analyzed noise performance theoretically. As a result, the current noise in our theory is well agreed with the measured noise at a low frequency below 3 kHz. From the x-ray irradiation measurements, ten divided signal groups are observed, which will be associated with the incident x-ray position pixel. The best energy resolution was 18 eV (FWHM) for 5.9 keV x-rays at 0.5 μV bias voltage.
Article: Characterization of Ir/Au pixel TES[Show abstract] [Hide abstract]
ABSTRACT: Signal shapes and noise characteristics of an asymmetrical ten-pixel Ir/Au-TES have been studied. The asymmetric design may be effective to realize an imaging spectrometer. Distinct two exponential decays observed for X-ray events are consistent with a two-step R–T curve. A theoretical thermal model for noise in multi-pixel devices reasonably explains the experimental data.Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 04/2006; 559(2):429-431. · 1.32 Impact Factor